Influence of formic acid and its salts on the elimination of the negative effect of zinc in portland cement

Influence of formic acid and its salts on the elimination of the negative effect of zinc in portland cement | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Influence of formic acid and its salts on the elimination of the negative effect of zinc in portland cement Pavel Šiler, Lukáš Matějka, Jiří Švec, Jiří Másilko, Vojtěch Florian, and 5 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-8459865/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract Cement is the most important binder in the construction industry, produced globally in substantial quantities. Due to the utilization of used tires as fuel in clinker burning and the incorporation of secondary raw materials with a higher zinc content, the quantity of zinc in cement is steadily increasing. Zinc in cement exhibits adverse properties, primarily due to a significant retardation of hydration. Formic acid and its salts appear to be effective accelerators for enhancing the hydration of cements with elevated zinc levels. Within the scope of this study, the influence of pure formic acid as well as sodium, potassium, and calcium formates was investigated. Zinc was introduced in the form of ZnO. The effect of zinc on hydration was monitored using isoperibolic calorimetry. The formation of new products was tracked via differential thermal analysis (DTA) and X-ray diffraction analysis (XRD). The compressive strength of the samples was also measured. The results indicate that the application of formic acid and its salts in zinc-doped cements leads to a substantial reduction in the time required for hydration and concurrently results in an increase in compressive strength, both in cements without zinc and in those doped with zinc. Thermal analysis Portland cement Zinc oxide Hydration retardation Setting accelerators Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 Figure 9 Figure 10 Figure 11 1. Introduction Portland cement, often combined with supplementary cementitious materials (SCMs) such as blast furnace slag and fly ash, is an extensively utilised binder for stabilising toxic wastes, including heavy metals. A key advantage of cementitious and pozzolanic binders lies in the high pH generated upon mixing with water. This alkaline environment facilitates the conversion of soluble metal compounds into sparingly soluble hydroxides. Furthermore, stabilisation with a cementitious matrix ensures the low leachability of these wastes [ 1 ]. The gel model provides a theoretical framework for understanding the effect of contaminants on hydration kinetics. This model posits the formation of a C-S-H gel membrane on the surface of silicate phase grains. This membrane permits the diffusion of water molecules towards the unhydrated core and the counter-diffusion of calcium and silicate ions into the solution. Diffusion across the C-S-H gel membrane is governed by the difference in osmotic potential across the membrane. The precipitation of portlandite from the solution and an excess of silicate anions leads to an increase in the osmotic pressure gradient, ultimately causing the rupture of the C-S-H gel membrane. This process is described as a periodically repeated cycle [ 1 ]. Among the many elements present in cement and SCMs that can adversely affect cement properties, zinc is particularly notable. Its primary sources include alternative fuels, such as tyres and other rubber products, and cement substitutes, namely metallurgical slags and fly ash. Zinc is widely recognised in cement industry research for its significant retardation of cement hydration and the resulting drastic reduction in early-age strengths. Zinc may be present either in a free form, as a constituent of specific clinker phases, or incorporated into a solid solution [ 2 ]. The initial theoretical explanation for the retarding effect of zinc proposed the formation of an impermeable zinc hydroxide membrane on the surface of the hydrating phases. However, Arliguie [ 3 ] later suggested that while an impermeable layer may not be requisite for effective retardation, zinc significantly delays the nucleation of stable hydration products, such as C-S-H gel and portlandite. Grandet [ 4 ], examining the clinker-solution interface in the presence of zinc, concluded that zinc hydrates precipitate before portlandite can be detected. Portlandite formation is only initiated when sufficient saturation with Ca 2+ and OH − ions is achieved. This strongly implies the consumption of these ions through the formation of zinc hydrates. This hypothesis is supported by Keppert [ 5 ], whose microstructural analysis using SEM and XRD confirmed the presence of Zn as hydrates within the interparticle space, rather than being incorporated into the C-S-H gel structure. In contrast, Weeks [ 6 ], studying the use of zinc production slag as aggregate in OPC, found no evidence of zinc-containing layer formation on the surface of either clinker or slag particles. He further affirmed that portlandite is only confirmed in hydrated cement after the conclusion of the induction period. The formation of the insoluble phase Ca(Zn(OH) 3 ) 2 ⋅2H 2 O leads to the depletion of Ca 2+ and OH − ions from the pore solution [ 7 ] [ 8 ]. Yousuf [ 9 ] confirmed the presence of this phase in ZnO-containing cement pastes through FTIR analysis. A high zinc content also retards C 3 A hydration, provided the SO 3 content in the system exceeds 2.5 wt. % [ 10 ]. The resultant reduction in the ion saturation of the pore solution suppresses the formation of C-S-H gel and portlandite. The findings of Ataie [ 11 ] on the retardation mechanism of OPC-ZnO hydration indicate a poisoning of the nucleation and growth of hydration products, which is consistent with the aforementioned principle of zinc retardation. The reactions culminating in the formation of Ca(Zn(OH) 3 ) 2 ⋅2H 2 O are presented in Equations ( 1 ), ( 2 ), and (3) [ 12 ] [ 13 ] [ 14 ]. $$\:{\text{Z}\text{n}}^{2+}+2\:\text{O}{\text{H}}^{-}\to\:\text{Z}\text{n}{\left(\text{O}\text{H}\right)}_{2}$$ 1 $$\:\text{Z}\text{n}{\left(\text{O}\text{H}\right)}_{2}+2\:\text{O}{\text{H}}^{-}\to\:\text{Z}\text{n}{\text{O}}_{2}^{2-}+2\:{\text{H}}_{2}\text{O}$$ 2 $$\:2\:\text{Z}\text{n}{\text{O}}_{2}^{2-}+{\text{C}}_{3}\text{S}/\text{O}-\text{C}{\text{a}}^{2+}+6\:{\text{H}}_{2}\text{O}\to\:{\text{C}}_{3}\text{S}/\text{O}-\text{C}\text{a}{\text{Z}\text{n}}_{2}{\left(\text{O}\text{H}\right)}_{6}\bullet\:2{\:\text{H}}_{2}\text{O}+2\:{\text{O}\text{H}}^{-}$$ 3 Ouki and Hills [ 15 ] investigated the microstructure of cement blended with various salts and observed that the presence of zinc led to an increase in the amount of unreacted cement. The retardation or delay of setting is desirable in certain applications of cementitious materials, such as high- performance concrete (HPC). Since HPC preparation often involves blended cement, plasticisers, and other admixtures, there is potential for utilising zinc salts as targeted setting retarders. Li et al. [ 16 ] explored the effects of zinc chloride and sulphate on hydration and ultimate compressive strength. Liu et al. [ 17 ] and Nochaiya et al. [ 18 ] discussed the impact of ZnO nanoparticles on the hydration, strength, and microstructure of cement pastes. Even the lowest dosage of nanoparticles was found to slow the cement setting, consequently reducing the early strength of the sample. However, after 3 days, the strengths of the samples with and without nanoparticles were comparable. Following 7 days of curing, the strengths of all nanoparticle-containing samples were higher than the reference. Calorimetric measurements indicated a slightly lower total heat of hydration when nanoparticles were used. The addition of nanoparticles also improved the pore size distribution, resulting in a more compact microstructure [ 17 ]. This strength increase is attributed to the pore-filling effect of the nanoparticles. In contrast, Liu et al. [ 17 ] reported the opposite outcome, where the final strength decreased with increasing nanoparticle content. Šiler et al. [ 19 ] examined the effect of zinc in the form of ZnO, Zn(NO 3 ) 2 , and ZnCl 2 on cement pastes, and in subsequent studies [ 20 ] [ 21 ], they introduced slag and fly ash into the same experimental setup. They determined that ZnO acts as the strongest retarder due to its low solubility. While ZnCl 2 accelerated hydration in the cement paste at a 1 wt. % addition, this acceleration was absent when combined with slag. Furthermore, a synergistic retarding effect was observed when zinc was combined with slag. A 15 wt. % addition of fly ash to cement causes further retardation of hydration reactions, primarily through the consumption of Ca 2+ ions by the fly ash particles. Accelerators are substances that, even in small quantities, speed up the hydration reactions of clinker phases and the formation of C-S-H gel. This leads to shorter setting times, faster development of early-age strengths, or both. They are employed, for example, to offset the effects of low temperatures or in mixtures with freezing point-lowering agents. Accelerators are also used in the production of precast concrete to facilitate faster demoulding, achieve a high-quality surface finish, or reduce curing time. However, the acceleration of hydration can potentially deteriorate the long-term mechanical properties and durability of the concrete. Consequently, alternative acceleration methods, such as optimising the cement composition or reducing the water-to-cement ratio, are preferred where feasible [ 22 ] [ 23 ] [ 24 ] [ 25 ]. Based on their chemical composition, accelerators can be classified into: Soluble inorganic salts of alkali and alkaline earth metals (Cl − , Br − , F − , I − , ClO 4 − , CO 3 2− , SCN − , SO 4 2− , S 2 O 3 2− , NO 2 − , NO 3 − , SiO 4 2− , Al(OH) 4 − , OH − ). Water-soluble organic compounds (e.g., triethanolamine (TEA) or calcium salts of lower organic acids such as formate, acetate, propionate, and butyrate) The efficiency of an accelerator depends on both the anion and the cation. Cations and anions can be organised into series based on their effectiveness in accelerating C 3 S hydration, with butyrate being reported as the most efficient [ 22 ] [ 23 ] [ 24 ] [ 25 ]. Matějka et al. [ 26 ] investigated the influence of thiocyanate-based accelerators (NaSCN and KSCN) on zinc-doped cement and found that they further retarded the setting of the contaminated cement. In a separate study, Matějka et al. [ 27 ] explored the effect of nitrate-based accelerators on zinc-doped cement. They concluded that all tested additives effectively reduced the setting time without compromising mechanical properties. The commercial accelerators were found to be significantly less effective than the pure nitrates, a result attributed to their complex composition and the dosage being optimised for different cement systems. Formate salts were introduced as setting accelerators in the latter half of the nineteenth century, primarily to counteract the retarding effects of water-reducing additives. Evidence suggests that calcium formate promotes the formation of ettringite and certain AFm phases that precipitate from the hydration of C 3 A in the presence of gypsum. Singh et al. [ 28 ] hypothesised that calcium formate accelerates the hydration of C 4 AF in oilwell cement by forming Fe 3+ -formate complexes, which exhibit higher solubility than other Fe 3+ hydrates. This mechanism is thought to disrupt the formation of any barrier layer on the surface of C 4 AF grains [ 29 ]. The hydration of alite is also reportedly accelerated by calcium formate addition, which promotes C-S-H gel formation and increases the overall content of chemically bound water. There appears to be a maximum optimal dosage of this compound, typically around 2 wt. % relative to cement, though this is dependent on the specific cement used. The optimal dose is also highly contingent on the presence of SCMs. For instance, pre-blending the cement with 40 wt. % fly ash was found to reduce the effectiveness of calcium formate in accelerating setting [ 30 ]. Singh et al. [ 28 ] offered a hypothesis to explain the mechanism of action of formate salts, proposing that formate anions adsorb onto the surface of C 3 S and create an easily rupturable layer. The continuous disruption of this layer promotes further hydration by enhancing the diffusion of water to the hydrating cement grain. A similar mechanism was proposed by Heikal et al. [ 31 ]. Calcium formate also influences the morphology of cement hydration products. Low doses of calcium formate resulted in the precipitation of small, compact, needle-like C-S-H gel crystals, while higher doses yielded bent-needle-like structures. The crystal size of ettringite also decreased, contributing to a more compact binder structure. The addition of a small dose of calcium formate, approximately 0.75 wt. %, was shown to reduce setting time by 30%, primarily by refining the pore structure [ 32 ]. The capacity of formate salts to accelerate setting and improve compressive strength appears to correlate with the C 3 A content of the cement. Levitt [ 33 ] investigated the development of cement paste doped with calcium formate using three different cements with C 3 A content ranging from 3 wt. % to 14 wt. %. The effectiveness of this compound in improving mechanical properties was observed to decrease with increasing C 3 A content. Furthermore, the efficacy in enhancing mechanical properties was greater when the C 3 A/SO 3 ratio exceeded 4, suggesting a preference for the formation of Fe 3+ complexes before adsorption onto hydrating C 3 S [ 34 ]. The increasing presence of zinc in cementitious systems constitutes a significant problem requiring effective mitigation strategies. While the effect of zinc in cement has been described in numerous publications, a universally effective method to eliminate its negative effects has yet to be fully established. This article is primarily aimed at demonstrating a potential pathway to mitigate zinc's adverse effect on hydration while simultaneously enhancing the properties of the resulting material. Furthermore, it incorporates information designed to foster a deeper understanding of the mechanism of zinc action in cement and the potential utility of accelerators based on formic acid and its salts. 2. Material and samples preparation Formic acid salts were synthesised by neutralising formic acid p.a. purity with either Ca(OH) 2 , NaOH or KOH. The purity of synthesised salts was confirmed using XRD analysis. The potassium formate was not used for further experiments due to difficulties with storage and preparing the samples. This compound exhibits a very high level of hygroscopicity. This caused the salt to dissolve in atmospheric moisture during the preparation of the samples, which caused inconsistencies in dosage and water-to-cement ratio. The research involved formulating cement matrices using a commercially sourced Ordinary Portland Cement (OPC) designated CEM I 42.5 R. This binder was procured from Mokrá-Českomoravský cement, a.s. (Heidelberg Cement Czech Republic). The complete chemical profile of this cement is delineated in Table 3 . All test compositions were batched with a constant water-to-cement ratio (w/c) of 0.4. The specific proportions and component quantities for each mix are summarised in Table 4 . Table 1 Composition of the OPC used in the samples. Cement (%) CaO 63.20 SiO 2 19.50 Al 2 O 3 4.70 Fe 2 O 3 3.30 MgO 1.50 SO 3 3.07 Cl − 0.066 K 2 O 0.78 Na 2 O 0.15 Insoluble 0.67 LOI 3.38 Table 2 Composition of samples doped with formates and formic acid for calorimetry Component CEM (g) H 2 O (g) ZnO (g) Additive (g) Ref. CEM I 250 100 Ref. CEM I + 1% Zn 250 100 6.20 Ref. CEM I + 5% Zn 250 100 31.10 HCOONa 1:0.5 500 200 6.20 2.6 1:1 500 200 6.20 5.2 1:2 500 200 6.20 10.4 1:5 500 200 6.20 26.0 HCOOK 1:0.5 500 200 6.20 3.20 1:1 500 200 6.20 6.40 1:2 500 200 6.20 12.90 1:5 500 200 6.20 32.20 (HCOO) 2 Ca 1:0.5 500 200 6.20 5.00 1:1 500 200 6.20 9.90 1:2 500 200 6.20 19.90 1:5 500 200 6.20 49.70 HCOOH 1:0.5 500 200 6.20 1.80 1:1 500 200 6.20 3.50 1:2 500 200 6.20 7.00 1:5 500 200 6.20 17.60 To study the influence of metal ions, every formulation was systematically spiked with ZnO powder. The ZnO quantity was precisely calculated to introduce 1 wt. % and 5 wt. % elemental zinc into the dry mass of the cement. Accelerator dosages were referenced using a molar equivalent basis relative to the lower 1 wt. % zinc loading. The mixing regimen commenced by thoroughly blending the cement with all powdered additives through initial manual agitation. This dry mix was then subjected to 30 seconds of mechanical agitation at a low speed using a benchtop mixer. Following this, the mixing water, which contained the pre − dissolved accelerator, was introduced, and the resulting slurry was homogenised for an additional 30 seconds at high speed. A one-minute (60 s) pause ensued, during which the bowl's interior was manually scraped to ensure full material inclusion and uniform consistency. The final mixing phase consisted of 120 seconds of high-speed mixing. The freshly prepared cement paste was subsequently cast into the appropriate vessels—be they moulds, measuring cells, or storage containers—according to the requirements of the planned investigation. Specimens were maintained in a controlled high − humidity chamber until the designated testing ages of 7 or 28 days were reached. For thermal (TG-DTG) and X-ray diffraction (XRD) assessments, the hydration process within the cement paste had to be halted definitively. The protocol for storage and hydration termination was strictly followed, according to the established RILEM recommendations [ 35 ]. The set specimens were broken into small fragments and immediately submerged twice for 15 minutes in anhydrous isopropyl alcohol, followed by two 15-minute soakings in acetone to extract the pore water fully. After the solvent treatments, the fragments underwent drying at 40°C overnight to remove residual organic compounds. They were then stored over silica gel to prevent any subsequent moisture uptake [ 35 ]. 3. Experimental methods Calorimetry Calorimetry technique was deployed to track the influence of zinc on the hydration progression and allows monitor overall material response in a practical setting [ 36 ]. Managing and predicting the thermal peak generated by the hydration reaction is paramount for massive concrete pours. Isoperibolic calorimetry has proven to be a suitable method for studying the effect of zinc on cement [ 37 ]. Isoperibolic calorimetry is a frequent choice for tracking the thermal development during the reaction of cementitious binders [ 38 ] [ 39 ] [ 40 ]. The underlying principle entails measuring the sample's internal temperature fluctuations while its surroundings are held at a stable temperature. The cumulative heat release is ascertained via post − test numerical integration of the temperature data, using calibration factors for the apparatus [ 36 ]. Since the sample temperature naturally increases due to the exothermic hydration reaction (reflecting practical conditions), combining this approach with the isothermal method offers a comprehensive view of the reaction mechanisms [ 36 ].) X − ray Diffraction (XRD) represents a non-destructive method commonly used for the analysis of crystallised substances. The resultant X-ray diffractogram furnishes characteristic structural information, which is key to both the identification and absolute quantification of the various crystalline phases present in the matrix [ 41 ] [ 42 ]. The X − ray crystallographic analysis was performed on an Empyrean X-Ray diffractometer (Malvern Panalytical, Royston, UK). The instrument employed Bragg–Brentano parafocusing geometry and CuKα radiation. Data were collected across a 2θ range extending from 5∘ to 120∘, using an angular increment of 0.013∘2θ and a 25-second signal acquisition time per step. Automated divergence slits were utilised to maintain a constant area of specimen exposure. To optimise the signal quality, four individual scans were recorded and mathematically summed. 4. Result and discussion The effects of formic acid and formates – Isoperibolic calorimetry The calorimetric measurements of cement-ZnO samples doped with HCOONa are presented in Fig. 1 . Even low doses of HCOONa accelerated the setting of these samples. The induction period decreased with increasing doses up to about 50 h for the highest dose. This shows that sodium formate has comparable effectiveness to nitrate-based accelerators [ 27 ]. There appears to be a linear correlation between setting time, maximum temperature and dose up to a 1:2 ratio of additives. Even though the doses are doubled in each sample, the difference in setting time between each sample is roughly the same. This points to the optimal effective dose being the 1:2 ratio of this additive. The setting of cement-ZnO samples doped with HCOOK is presented in Fig. 2 . The behaviour of these samples was very similar to that of previous samples doped with HCOONa, which is to be expected. Potassium salts generally have lower performance as accelerators due to increased heating during mixing and increased porosity [ 32 ]. Higher alkali content harms the stability of ettringite and mechanical properties, depending on the composition of the used cement. The total evolved heat of both alkali salts follows a similar trend. The samples with lower doses of HCOONa or HCOOK showed slightly lower total evolved heat compared to pure cement and cement with ZnO. This indicates a slightly lower overall hydration degree, even with accelerated hydration. The sample with a 1:2 ratio of additives in both types of samples exhibited comparable total evolved heat to both references. Compared to alkali formate salts, calcium formates caused significant acceleration of setting even at the lowest dose. The lowest dose of calcium formate reduced setting time to around 60 h, comparable to the highest doses of HCOONa and HCOOK, as seen in Fig. 3 . The most effective dose appears to be a 1:2 ratio of zinc to accelerator. Increasing the dose beyond this ratio caused a change in the hydration mechanism. The largest dose of calcium formate caused a visible increase in the first hydration peak and a decrease in the height of the main hydration peak. This indicates an effective limit to how much calcium formate can be used relative to the cement and zinc contaminant amount before any detrimental effects. The samples containing 1 : 0,5 to 2 show a clear increase in total evolved heat, indicating a higher hydration degree than the reference cement. The sample with the highest dose of calcium formate had significantly lower total evolved heat, which correlates with lower hydration degree and retarded setting. This indicates the maximum effective dose of this compound for accelerating the setting of the cement-ZnO system. A set of samples of the cement-ZnO system doped with formic acid was prepared to investigate the effect of HCOO − . Results of these samples are presented in Fig. 4 . Here, it is apparent that low doses of formic acid retard setting, but higher doses accelerate setting. An acidic accelerator is not comparable to salts due to the drastically different pH of the pore solution. A low pH environment leaches cations from cement phases, drastically affecting the solubility of ZnO in the pore solution. Zinc oxide is an amphoteric compound. In low pH environments, it dissolves into free Zn 2+ that can be incorporated into various phases. In contrast, it forms various Zn(OH) x y− species in high pH that precipitate out of the pore solution, depleting calcium ions [ 43 ]. While a low pH environment retards the setting of OPC, it dissolves ions into the pore solution, promoting the formation of hydration products and thus increasing the hydration degree of cement phases. That can result in an improvement of mechanical properties and a decrease in the overall porosity of the structure. This effect can be seen from the graph showcasing cumulative heat release during the calorimetric measurements. Only the lowest dose of HCOOH caused further retardation of setting and a decrease in cumulative heat, thus hydration degree. The second lowest dose did not noticeably affect the setting but slightly increased the hydration degree. The two highest doses of formic acid caused an acceleration of setting and higher released cumulative heat that references OPC. The effects of formates – Mechanical properties The graph presented in Fig. 5 shows the compressive strength of samples doped with formate salts and formic acid after 28 days of curing. Formic acid had a negative influence on compressive strength in most doses, which correlates with the results of calorimetric measurements, where low doses retarded setting. The hydration of ZnO-cement was accelerated only in very high doses. The lowest dose of salts did not noticeably impact the mechanical properties of the samples. The sodium and calcium salt slightly improved compressive strength compared to the reference CEM I and reference CEM I with ZnO. Both sodium and calcium formates effectively reduced the setting time, even at lower doses. The improvement of compressive strength by the addition of calcium formate confirms results in available publications. Calcium formate improves both early and late-stage mechanical properties by promoting the formation of C-S-H gel, combined water content and decreasing porosity. This improvement was demonstrated not only in OPC paste but also in mortars containing various SCMs, such as condensed silica fume, ground clay bricks, fly ash and GGBFS. Calcium formate salts were also very effective in supersulfonated cement with very high GGBFS content [ 31 ] [ 44 ] [ 45 ] [ 46 ] [ 47 ] [ 48 ] [ 49 ]. Samples with potassium formate showed lower compressive strength than the other accelerated samples, but were comparable to the reference CEM I. This could be caused by a similar effect as KSCN [ 26 ]. With increasing doses, the mechanical properties of samples doped with sodium and calcium formate improved to the second-highest dose. The compressive strength of the potassium formate-doped samples was comparable with the measurement error. The highest dose of all salts induced a small decrease in compressive strength, but not lower than the reference CEM I. The effects of formates – TG-DTG The TG-DTG analysis was performed on samples containing 0, 1 and 5 wt. % of zinc. Zinc-free samples were analysed to compare phase composition differences caused by the presence of zinc ions. The high zinc content samples were prepared to determine the presence of zinc-containing phases. The doses of accelerators were chosen based on the results of isoperibolic calorimetry and experience with other additives studied in our other papers [ 27 ] [ 26 ]. These doses were a 1:1 ratio of zinc to additive (Min dose) and a 1:5 ratio of zinc to additive (Max dose). The TG-DTG analysis of samples without zinc after 7 days of curing is presented in Fig. 6 . The biggest difference between the samples doped with sodium and calcium formate is in the height of the decomposition peaks at around 120°C, 160°C and overall mass loss. The decomposition peak at around 120°C can be attributed to C-S-H gel [ 50 ]. The sodium formate-doped samples showed a lower amount of these hydration products and a slight shift of this peak to the right, after 7 days of curing, compared to pure OPC. This points to a more amorphous structure of hydration products and a lower hydration degree, as seen from the slightly lower total mass loss. One of the possible explanations as to why this sample is less hydrated even when the accelerator was added is a drastic increase in the alkali content of the pore solution. It appears that when contamination is not present, sodium formate is not a very effective accelerator, which could explain why sodium formate is not widely used compared to sodium nitrate. The height of the portlandite decomposition peak at around 420°C [ 51 ] was comparable to that of the reference samples in both samples. This means that the silicate phases are not less hydrated, but the composition of the hydration products is different. Different composition of the hydration products is visible from the significantly lower decomposition peak of ettringite at around 160–170°C [ 52 ] [ 53 ]. The detrimental effect of high alkali content on the formation and stability of ettringite and monosulphate was mentioned in paper [ 26 ]. The significant increase in carbonate content, as can be seen from decomposition peaks between 600 and 800°C, is most likely the result of higher carbonation caused by increased alkali content of the pore solution [ 54 ] [ 55 ] [ 56 ]. The calcium formate appears to be a generally effective hydration accelerator, as seen from the slightly higher mass loss of main hydration products compared to OPC. This salt also did not significantly impact the content of ettringite, which is important for accelerating the setting of zinc-contaminated cement. After 7 days of curing, these samples show a slightly higher amount of silicate hydration products and portlandite. The higher carbonate content in these samples can be explained by the higher carbonation of the samples due to the added soluble calcium ions in the pore solution. After 28 days of curing, as can be seen from Fig. 7 , it is apparent that lower doses of HCOONa had a detrimental effect on hydration based on the lower silicate hydrate decomposition peak, lower portlandite decomposition peak and overall lower total mass loss. On the other hand, the higher dose caused a slight increase in silicate hydrate content but drastically lower Aft/AFm content. The total mass loss of the samples with a high amount of added HCOONa was comparable to that of the reference cement. These results could point to competing effects of Na + and HCOO − on hydration mechanisms. While increasing the alkali content of the pore solution destabilises ettringite and is detrimental to the hydration mechanism of OPC, increasing the content of formate ions promotes hydration of the silicate phase, counteracting the effects of Na + . The calcium formate-doped samples behaved very differently. The composition of these samples was very similar to the reference sample. The most important difference was the slightly higher silicate hydrate and portlandite content when a higher dose was used. This further confirms that this salt is an effective accelerator without significant negative side effects. The zinc content in the system influences the cement's hydration mechanism and effectiveness. After 7 days of curing, the cement-ZnO samples doped by sodium formate, shown in Fig. 8 , had a higher mass loss of silicate hydrates but with significantly smaller and wider decomposition peaks. Along with the significantly higher portlandite decomposition peak, it shows that adding sodium formate caused an acceleration of hydration. This effect was seen in calorimetry results. Compared to the reference, the wider decomposition peak indicates the higher amorphous content of these samples. Increasing the dose of sodium formate caused an increase in the height of the silicate hydrate peak, confirming increased acceleration with increased dose. The increased height of the peak at around 170°C [ 55 ] [ 56 ] indicates a higher ettringite content than the reference sample. The decomposition peak at around 240°C was present in many previous samples containing sodium salts and indicates the presence of either a monocarbonate phase or another aluminate hydrate [ 57 ]. Both samples demonstrated noticeably higher total mass loss than the reference, which increased slightly with increased dose. This indicates a higher hydration degree. The calcium formate-containing samples exhibited higher C-S-H gel and ettringite decomposition peaks. Along with the higher decomposition peak of portlandite, this points to accelerated hydration and higher crystalline content than the sodium formate-doped samples. The lower portlandite content in the samples with higher doses of calcium formate can be explained by the significantly larger carbonatation of these samples, as seen from the significantly larger carbonate decomposition peak. The TG-DTG analysis of the samples after 28 days of curing is presented in Fig. 9 . The HCOONa-doped samples showed comparable content of C-S-H gel and silicate hydrates to the reference sample in the case of the smaller dose. The sample with a higher dose showed a higher content of silicate hydrates but with less crystalline structure, as is evident from the shift of the 120°C decomposition peak to the right [ 58 ] [ 59 ]. The content of ettringite did not significantly increase between measurements, with its content decreasing with increased dose. The decrease in ettringite content with increasing alkali content was discussed in our previous published work Matejka et al [ 26 ]. The height of the portlandite decomposition peak seems to increase slightly with increasing doses of sodium formate, confirming increased hydration acceleration. The overall mass loss increased with an increased dose of this additive, but it is slightly lower than the total mass of the reference. This shows that while the setting is accelerated, as was seen in the calorimetry results, the content of some hydration products is increased at the expense of others. The samples doped with Ca(HCOO) 2 showed a comparable amount of silicate hydration products to HCOONa cement samples and the same dose-dependent trend. The main difference was a slightly more crystalline structure, as seen from the smaller shift of this decomposition peak to the right compared to sodium formate-doped samples. The ettringite content based on the decomposition peak height at around 160°C was higher than in the case of sodium formate-doped samples but lower than the reference. The promotion of ettringite formation by calcium formate is discussed in multiple articles [ 44 ] [ 45 ] [ 46 ] [ 47 ]. The height of the portlandite decomposition peaks seems to be comparable to the reference sample and slightly higher than the HCOONa-doped samples. The carbonate decomposition peaks of the sample with a maximum dose of Ca(HCOO) 2 are drastically larger than all other samples. This is due to increased carbonation of the sample caused by a large amount of added soluble calcium. The overall mass loss of the Ca(HCOO) 2 -doped samples is comparable to or somewhat larger than that of the reference sample. This points to larger similarities in the composition of these samples to the reference than the HCOONa-doped. It can thus be concluded that while Ca(HCOO) 2 is a more effective accelerator of the setting of a cement-zinc system than HCOONa, it does not change the hydration mechanism as much. Increasing the content of zinc has a large impact on the hydration kinetics and mechanism. The TG-DTG measurements of cement paste containing 5 wt. % of zinc and doped with sodium and calcium formate are shown in Fig. 10 and Fig. 11 . After 7 days of curing, the HCOONa-doped ZnO-cement samples had significantly different composition from the reference ZnO-OPC sample. The sample with minimal dose had a lower decomposition peak at around 80°C corresponding to C-S-H gel C [ 58 ] [ 59 ] and a lower peak at around 170°C corresponding to ettringite and unreacted gypsum [ 52 ] [ 53 ]. The decomposition peak of portlandite at around 420°C is slightly higher, indicating a slight acceleration of setting [ 60 ]. The overall mass loss is somewhat low, mainly due to lower silicate hydrate content. The maximum dose sample had a different composition from the reference and the previous sample. The TG-DTG curve had a wider C-S-H decomposition peak at around 100°C [ 58 ] [ 59 ], probably due to lower crystallinity and unreacted water, and a new peak at around 240°C [ 57 ]. This decomposition peak can be attributed to C 3 AH 6 aluminate hydrate that probably precipitated due to low ettringite content caused by destabilisation of ettringite through high alkali content in the pore solution and high ionic strength [ 61 ]. The higher decomposition peak of portlandite at around 420°C indicates a higher acceleration of setting than the lower dose. The higher decomposition peak between 600 and 800°C [ 54 ] [ 55 ] [ 56 ] is probably due to the increased content of carbonates in the sample, due to the presence of Na + ions. The calcium formate, compared to the HCOONa sample, shows acceleration of hydration. The decomposition peaks of C-S-H hydrates and ettringite are significantly higher than those of the sodium formate-doped and reference samples. The decomposition peak of portlandite at around 420°C is also visibly higher, proving the acceleration of setting [ 51 ]. The total mass loss increases with increasing dose of calcium formate. Thus, this compound effectively accelerates the setting event at 5 wt. % of zinc in the system. After 28 days of curing, as shown in Fig. 11 , the HCOONa-doped samples resemble the reference cement sample but have a lower ettringite and portlandite content. Similar development of composition is visible in samples doped with calcium formate. Neither of the doses drastically increased the content of ettringite and portlandite. The total mass loss of sodium and calcium formate-doped samples was lower than that of the reference. This could mean that at 5 wt. % of zinc, these compounds can only accelerate hydration in the early stages of curing. The effects of formates – XRD XRD analyses provide structural information about the crystalline phases in the cement samples. This means that it does not represent the sample's total phase composition but the crystalline phase's relative composition. Coupled with TG-DTG analysis, it is possible to identify the mineral phases present in the samples and their changes. Phase composition of reference samples is shown in Table 3 . The XRD results of the samples doped with sodium formate are presented in Table 4 . The most important trends are the almost constant content of portlandite in samples without zinc and with 1 wt. % of zinc. The amount of portlandite does not significantly change with increasing dose or between curing times. This correlates with the TG-DTG results, where the portlandite decomposition peak had roughly the same height regardless of the dose and curing time. The explanation could be that sodium formate accelerates the early stages of hydration. Compared to the composition of the reference samples, the portlandite content is higher after 7 days of curing but lower after 28 days. This is most likely due to higher amorphous content, as acceleration was seen in the calorimetric results. Another important change is the ettringite content. In all samples with HCOONa, the amount of ettringite in early stages of hydration was either very low or below the detection limit. This could again be caused by higher amorphous content, but the decomposition peaks of ettringite were lower in the TG-DTG results. It can be concluded that HCOONa does not promote the formation of ettringite in the cement-ZnO system. Table 3 Relative percentage composition of the reference samples Dose and content of zinc 0% Zn 1% Zn 5% Zn Days of curing 7 d 28 d 7 d 28 d 7 d 28 d C 3 S 27 19 57 27 63 33 C 2 S 18 19 16 19 14 19 C 4 AF 5 4 5 4 5 4 Portlandite 36 40 6 34 1 24 Ettringite 6 8 6 6 2 5 Calcite 6 8 7 6 5 7 ZnO 5 1 CaZn 2 (OH) 6 ∙2 H 2 O 4 6 Ca 4 Al 2 O 6 (CO 3 )(OH) 12 ·5 H 2 O 1 2 5 2 2 Table 4 The relative phase composition of samples doped with HCOONa Dose and content of zinc Min Max Min 1% Max 1% Min 5% Max 5% Days of curing 7 d 28 d 7 d 28 d 7 d 28 d 7 d 28 d 7 d 28 d 7 d 28 d C 3 S 33 32 34 33 40 38 41 38 62 55 62 58 C 2 S 18 19 17 20 20 21 19 22 18 19 17 16 C 4 AF 7 5 7 6 5 5 6 5 7 6 7 6 Portlandite 36 33 36 32 29 25 26 23 1 5 3 6 Ettringite 4 4 3 3 1 3 1 Calcite 6 6 6 5 5 4 5 6 4 5 3 5 SiO 2 1 1 1 ZnO 5 1 5 1 Ca(Zn 2 (OH) 6 )·2 H 2 O 4 2 3 Monosulphate Ca 4 Al 2 O 6 (CO 3 )(OH) 12 ·5 H 2 O 1 1 1 2 1 1 2 1 3CaO·Al 2 O 3 ·(HCOO) 2 Ca·11 H 2 O 1 1 1 1 1 3 The XRD results of samples doped with calcium formate are presented in Table 5 . At first glance, it is apparent that calcium formate had a higher content of portlandite than samples with sodium formate. This correlates with the TG-DTG results, where calcium formate-doped samples exhibited a larger Portlandite decomposition peak than sodium formate-doped samples, particularly after 28 days of curing. This confirms that calcium formate is a more effective accelerator of hydration than sodium formate. The content of ettringite was also higher, especially in the early stages of development. This means that calcium formate promotes the formation of ettringite, which seems to be crucial for accelerating the setting of zinc-contaminated cement. The increase in ettringite content in cement mortars containing calcium formate was described in multiple publications. Higher content of ettringite was found in both early and late stages of hydration. In these articles, a lower content of unhydrated C 3 A and gypsum was observed. Thus, the promotion of ettringite can be caused by increased availability of sulphate ions in the pore solution through consumption of available gypsum [ 44 ] [ 45 ] [ 46 ] [ 47 ]. Table 5 The relative phase composition of samples doped with (HCOO) 2 Ca Dose and content of zinc Min Max Min 1% Max 1% Min 5% Max 5% Days of curing 7 d 28 d 7 d 28 d 7 d 28 d 7 d 28 d 7 d 28 d 7 d 28 d C 3 S 33 32 34 33 40 38 41 38 62 55 62 58 C 2 S 18 19 17 20 20 21 19 22 18 19 17 16 C 4 AF 7 5 7 6 5 5 6 5 7 6 7 6 Portlandite 36 39 35 37 28 31 29 31 4 8 2 8 Ettringite 5 3 7 4 4 2 5 3 5 3 5 3 Calcite 5 6 4 8 6 8 5 6 4 5 5 6 SiO 2 ZnO 1 1 1 1 3 1 8 1 Ca(Zn 2 (OH) 6 )·2 H 2 O Monosulphate Ca 4 Al 2 O 6 (CO 3 )(OH) 12 ·5 H 2 O 1 1 1 3 1 1 1 1 3CaO·Al 2 O 3 ·(HCOO) 2 Ca·11 H 2 O 1 2 1 1 2 1 1 1 3 1 5. Conclusion The The aim of this work was primarily to show a possible way to eliminate the negative effect of zinc on cement hydration using hydration accelerators. Formate salts are shown to be the most effective accelerators out of all tested compounds and products. These compounds drastically decreased setting time to the point of being comparable to pure reference OPC. There was also a slight improvement in the compressive strength of HCOONa and (HCOO) 2 Ca doped samples, probably due to a decrease in porosity of the samples. The calcium formate was the most effective, drastically shortening setting time even in comparison to sodium and potassium formateUsing this accelerator, it is possible to reduce the time to reach the main hydration peak from 170 hours to less than 25 hours in the presence of 1% zinc. The probable cause of the different effectiveness of these compounds was the added soluble calcium, which promotes the formation of cement hydrates. The increased content of ettringite, in the presence of (HCOO) 2 Ca, was indicative of effective acceleration of hydration of the ZnO-cement system. The possible mechanism behind the high effectiveness of formates could be the disruption of the Ca(Zn 2 (OH) 6 )·2 H 2 O layer on the surface of silicate cement phase grains due to the high diffusion rate of HCOO − through C-S-H gel. Declarations Conflict of interest The authors declare no conflict of interest. Author Contribution PS contributed to conceptualisation and editing, contributed to draft preparation, investigation, and formal analysis. LM contributed to draft preparation, investigation, and formal analysis. JS contributed to the investigation, data curation, formal analysis, and methodology. JM contributed to the investigation, data curation, formal analysis, and methodology. VF contributed to sample preparation and basic characterization, OK contributed to sample preparation and data evaluation, JK contributed to the investigation, data curation, formal analysis, and methodology. RN contributed to the investigation, data curation, formal analysis, and methodology. MS contributed to the investigation and data curation. FS contributed to administration and supervision. Acknowledgement This outcome has been achieved with the financial support of the project GA19-16646S, "The elimination of the negative impact of zinc in Portland cement by accelerating concrete admixtures", with financial support from the Czech Science Foundation. References YOUSUF, M.; MOLLAH, A.; VEMPATI, Rajan; LIN, T.-C. a COCKE, David. The interfacial chemistry of solidification/stabilization of metals in cement and pozzolanic material systems. Waste Management . 1995, issue 15, č. 2, s. 137–148. ISSN 0956053X. Available from: https://doi.org/10.1016/0956-053X(95)00013-P . ANDRADE, F.R.D; MARINGOLO, V a KIHARA, Y. Incorporation of V, Zn and Pb into the crystalline phases of Portland clinker. online. Cement and Concrete Research . 2003, issue 33, č. 1, s. 63–71. ISSN 00088846. Available from: https://doi.org/10.1016/S0008-8846(02)00928-6 . [cit. 2024-05-19]. ARLIGUIE, G.; OLLIVIER, J.P. a GRANDET, J. Etude de l'effet retardateur du zinc sur l'hydratation de la pate de ciment Portland. Cement and Concrete Research . 1982, issue 12, č. 1, s. 79–86. ISSN 00088846. Available from: https://doi.org/10.1016/0008-8846(82)90101-6 . GRANDET, J. a OLLIVIER, J.P. Study of the contact zone between zinc and Portland cement paste. Cement and Concrete Research . 1980, issue 10, č. 6, s. 759–770. ISSN 00088846. Available from: https://doi.org/10.1016/0008-8846(80)90004-6 . KEPPERT, Martin; JERMAN, Miloš; SCHEINHERROVÁ, Lenka; REITERMAN, Pavel; DOUŠOVÁ, Barbora et al. Influence of free and sorbed zinc on cement hydration. Journal of Thermal Analysis and Calorimetry . 2019, issue 138, č. 3, s. 1935–1943. ISSN 1388–6150. Available from: https://doi.org/10.1007/s10973-019-08200-0 . WEEKS, Caroline; HAND, Russell a SHARP, John. Retardation of cement hydration caused by heavy metals present in ISF slag used as aggregate. Cement and Concrete Composites . 2008, issue 30, č. 10, s. 970–978. ISSN 09589465. Available from: https://doi.org/10.1016/j.cemconcomp.2008.07.005 . GINEYS, N.; AOUAD, G. a DAMIDOT, D. Managing trace elements in Portland cement – Part I: Interactions between cement paste and heavy metals added during mixing as soluble salts. Cement and Concrete Composites . 2010, issue 32, č. 8, s. 563–570. ISSN 09589465. Available from: https://doi.org/10.1016/j.cemconcomp.2010.06.002 . GINEYS, N.; AOUAD, G. a DAMIDOT, D. Managing trace elements in Portland cement – Part II: Comparison of two methods to incorporate Zn in a cement. Cement and Concrete Composites . 2011, issue 33, č. 6, s. 629–636. ISSN 09589465. Available from: https://doi.org/10.1016/j.cemconcomp.2011.03.008 . YOUSUF, M.; MOLLAH, A.; HESS, Thomas; TSAI, Yung-Nien a COCKE, David. An FTIR and XPS investigations of the effects of carbonation on the solidification/stabilization of cement based systems-Portland type V with zinc. Cement and Concrete Research . 1993, issue 23, č. 4, s. 773–784. ISSN 00088846. Available from: https://doi.org/10.1016/0008-8846(93)90031-4 . ARLIGUIE, G. a GRANDET, J. Influence de la composition d'un ciment portland sur son hydration en presence de zinc. Cement and Concrete Research . 1990, issue 20, č. 4, s. 517–524. ISSN 00088846. Available from: https://doi.org/10.1016/0008-8846(90)90096-G . ATAIE, Feraidon; JUENGER, Maria; TAYLOR-LANGE, Sarah a RIDING, Kyle. Comparison of the retarding mechanisms of zinc oxide and sucrose on cement hydration and interactions with supplementary cementitious materials. Cement and Concrete Research . 2015, issue 72, s. 128–136. ISSN 00088846. Available from: https://doi.org/10.1016/j.cemconres.2015.02.023 . GINEYS, N.; AOUAD, G.; SORRENTINO, F. a DAMIDOT, D. Incorporation of trace elements in Portland cement clinker: Thresholds limits for Cu, Ni, Sn or Zn. Cement and Concrete Research . 2011, issue 41, č. 11, s. 1177–1184. ISSN 00088846. Available from: https://doi.org/10.1016/j.cemconres.2011.07.006 . LAGO, Fernanda; GONçALVES, Jardel; DWECK, Jo a CUNHA, Armando. Evaluation of Influence of Salt in the Cement Hydration to Oil Wells. Materials Research . 2017, issue 20, č. 2, s. 743–747. ISSN 1980–5373. Available from: https://doi.org/10.1590/1980-5373-mr-2017-0049 . CHEN, Q.Y.; TYRER, M.; HILLS, C.D.; YANG, X.M. a CAREY, P. Immobilisation of heavy metal in cement-based solidification/stabilisation: A review. Waste Management . 2009, issue 29, č. 1, s. 390–403. ISSN 0956053X. Available from: https://doi.org/10.1016/j.wasman.2008.01.019 . OUKI, S.K a HILLS, C.D. Microstructure of Portland cement pastes containing metal nitrate salts. Waste Management . 2002, issue 22, č. 2, s. 147–151. ISSN 0956053X. Available from: https://doi.org/10.1016/S0956-053X(01)00063-0 . LI, Xiang; YIN, Xiao; MA, Bao; WU, Bei; CHEN, Quanbin et al. Investigation on Hydration Characteristics of Zinc-Doped Portland Cement Pastes. Advanced Materials Research . 2010, issue 168–170, s. 623–627. ISSN 1662–8985. Available from: https://doi.org/10.4028/www.scientific.net/AMR.168-170.623 . LIU, Jintao; JIN, Hang; GU, Chunping a YANG, Yang. Effects of zinc oxide nanoparticles on early-age hydration and the mechanical properties of cement paste. Construction and Building Materials . 2019, issue 217, s. 352–362. ISSN 09500618. Available from: https://doi.org/10.1016/j.conbuildmat.2019.05.027 . NOCHAIYA, Thanongsak; SEKINE, Yoshika; CHOOPUN, Supab a CHAIPANICH, Arnon. Microstructure, characterizations, functionality and compressive strength of cement-based materials using zinc oxide nanoparticles as an additive. Journal of Alloys and Compounds . 2015, issue 630, s. 1–10. ISSN 09258388. Available from: https://doi.org/10.1016/j.jallcom.2014.11.043 . ŠILER, Pavel; KOLÁŘOVÁ, Iva; NOVOTNÝ, Radoslav; MÁSILKO, Jiří; POŘÍZKA, Jaromír et al. Application of isothermal and isoperibolic calorimetry to assess the effect of zinc on cement hydration. online. Journal of Thermal Analysis and Calorimetry . 2018, issue 133, č. 1, s. 27–40. ISSN 1388–6150. Available from: https://doi.org/10.1007/s10973-017-6815-1 . [cit. 2024-05-08]. ŠILER,; KOLÁŘOVÁ, ; NOVOTNÝ, ; MÁSILKO, ; BEDNÁREK, et al. Application of Isothermal and Isoperibolic Calorimetry to Assess the Effect of Zinc on Hydration of Cement Blended with Slag. online. Materials . 2019, issue 12, č. 18. ISSN 1996 – 1944. Available from: https://doi.org/10.3390/ma12182930 . [cit. 2024-05-11]. ŠILER, Pavel; KOLÁŘOVÁ, Iva; NOVOTNÝ, Radoslav; MÁSILKO, Jiří; BEDNÁREK, Jan et al. Use of Isothermal and Isoperibolic Calorimetry to Study the Effect of Zinc on Hydration of Cement Blended with Fly Ash. online. Materials . 2020, issue 13, č. 22. ISSN 1996 – 1944. Available from: https://doi.org/10.3390/ma13225215 . [cit. 2024-05-11]. Advanced cementing materials: Controlling hydration development Accelerating admixtures for concrete . 2007. Available from: https://www.sintef.no/globalassets/sintef-byggforsk/coin/sintef-reports/sbf-bk-a07025_accelerating-admixtures-for-concrete.pdf . Report on Chemical Admixtures for Concrete . American Concrete Institute, 2010. Available from: https://www.concrete.org/store/productdetail.aspx?ItemID=212310 &Format=DOWNLOAD&Language=English&Units=US_Units. AïTCIN, Pierre-Claude a FLATT, Robert. Science and technology of concrete admixtures . Woodhead Publishing series in civil and structural engineering, no. 59. Amsterdam: Elsevir, 2016. ISBN 978-0-08-100693-1. RIXOM, M. a MAILVAGANAM, N.P. Chemical admixtures for concrete . 3rd ed. New York: Routledge, 1999. ISBN 04-192-2520-X. MATEJKA, Lukas; SILER, Pavel; NOVOTNY, Radoslav; SVEC, Jiri; MASILKO, Jiri et al. The thermal analysis of zinc oxide-contaminated Portland cement blended with thiocyanates and determination of their effect on hydration and properties. online. Journal of Thermal Analysis and Calorimetry . 2023, issue 148, č. 4, s. 1321–1349. ISSN 1388–6150. Available from: https://doi.org/10.1007/s10973-022-11666-0 . [cit. 2025-07-06]. MATEJKA, Lukas; SILER, Pavel; SVEC, Jiri; MASILKO, Jiri; KOPLIK, Jan et al. Comparison of commercial nitrate-based accelerators and their pure constituents on hydration kinetics, composition, and hydration degree of zinc oxide blended Portland cement. online. Journal of Thermal Analysis and Calorimetry . ISSN 1388–6150. Available from: https://doi.org/10.1007/s10973-025-14193-w . [cit. 2025-07-06]. SINGH, N.B. a ABHA, Km. Effect of calcium formate on the hydration of tricalcium silicate. Cement and Concrete Research . 1983, issue 13, č. 5, s. 619–625. ISSN 00088846. Available from: https://doi.org/10.1016/0008-8846(83)90050-9 . DORN, Tobias; BLASK, Oliver a STEPHAN, Dietmar. Acceleration of cement hydration – A review of the working mechanisms, effects on setting time, and compressive strength development of accelerating admixtures. online. Construction and Building Materials . 2022, issue 323. ISSN 09500618. Available from: https://doi.org/10.1016/j.conbuildmat.2022.126554 . [cit. 2025-06-17]. HEMALATHA, T. a SASMAL, Saptarshi. Early-age strength development in fly ash blended cement composites: investigation through chemical activation. online. Magazine of Concrete Research . 2019, issue 71, č. 5, s. 260–270. ISSN 0024-9831. Available from: https://doi.org/10.1680/jmacr.17.00336 . [cit. 2025-06-17]. HEIKAL, Mohamed. Effect of calcium formate as an accelerator on the physicochemical and mechanical properties of pozzolanic cement pastes. Cement and Concrete Research . 2004, issue 34, č. 6, s. 1051–1056. ISSN 00088846. Available from: https://doi.org/10.1016/j.cemconres.2003.11.015 . WANG, Yifei; LEI, Lei; LIU, Jianhui; MA, Yihan; LIU, Yi et al. Accelerators for normal concrete: A critical review on hydration, microstructure and properties of cement-based materials. online. Cement and Concrete Composites . 2022, issue 134. ISSN 09589465. Available from: https://doi.org/10.1016/j.cemconcomp.2022.104762 . [cit. 2025-03-27]. LEVITT, Maurice. Precast Concrete: Materials, manufacture, properties and usage . online. 1st. CRC Press, 1982. ISBN 9780429208461. Available from: https://doi.org/10.4324/9780203490570 . [cit. 2025-06-17]. SUH, Jung-Il; YUM, Woo; JEONG, Yeonung; PARK, Hong-Gun a EUN OH, Jae. The cation-dependent effects of formate salt additives on the strength and microstructure of CaO-activated fly ash binders. online. Construction and Building Materials . 2019, issue 194, s. 92–101. ISSN 09500618. Available from: https://doi.org/10.1016/j.conbuildmat.2018.11.008 . [cit. 2025-03-27]. SNELLINGS, Ruben; CHWAST, Jacek; CIZER, Özlem; DE BELIE, Nele; DHANDAPANI, Yuvaraj et al. RILEM TC-238 SCM recommendation on hydration stoppage by solvent exchange for the study of hydrate assemblages. Materials and Structures . 2018, issue 51, č. 6. ISSN 1359–5997. Available from: https://doi.org/10.1617/s11527-018-1298-5 . BRANDŠTETR, J; POLCER, J; KRÁTKÝ, J; HOLEŠINSKÝ, R a HAVLICA, J. Possibilities of the use of isoperibolic calorimetry for assessing the hydration behavior of cementitious systems. Cement and Concrete Research . 2001, issue 31, č. 6, s. 941–947. ISSN 00088846. Available from: https://doi.org/10.1016/S0008-8846(01)00495-1 . ŠILER, Pavel; KOLÁŘOVÁ, Iva; NOVOTNÝ, Radoslav; MÁSILKO, Jiří; POŘÍZKA, Jaromír et al. Application of isothermal and isoperibolic calorimetry to assess the effect of zinc on cement hydration. Journal of Thermal Analysis and Calorimetry. 2018, issue 133, č. 1, s. 27–40. ISSN 1388–6150. Available from: https://doi.org/10.1007/s10973-017-6815-1 . SILER, P.; KRATKY, J. a DE BELIE, N. Isothermal and solution calorimetry to assess the effect of superplasticizers and mineral admixtures on cement hydration. online. Journal of Thermal Analysis and Calorimetry . 2012, issue 107, č. 1, s. 313–320. ISSN 1388–6150. Available from: https://doi.org/10.1007/s10973-011-1479-8 . [cit. 2024-05-08]. ŠILER, Pavel; BAYER, Petr; SEHNAL, Tomáš; KOLÁŘOVÁ, Iva; OPRAVIL, Tomáš et al. Effects of high-temperature fly ash and fluidized bed combustion ash on the hydration of Portland cement. online. Construction and Building Materials . 2015, issue 78, s. 181–188. ISSN 09500618. Available from: https://doi.org/10.1016/j.conbuildmat.2015.01.032 . [cit. 2024-05-11]. ŠILER, Pavel; KOLÁŘOVÁ, Iva; KRÁTKÝ, Josef; HAVLICA, Jaromír a BRANDŠTETR, Jiří. Influence of superplasticizers on the course of Portland cement hydration. online. Chemical Papers . 2014, issue 68, č. 1. ISSN 1336–9075. Available from: https://doi.org/10.2478/s11696-013-0413-x . [cit. 2025-12-05]. Characterization, testing, and reinforcing materials of biodegradable composites. In: Biodegradable and biocompatible polymer composites: processing, properties and applications . Woodhead Publishing series in composites science and engineering. Duxford: Woodhead Publishing, Elsevier, 2018, s. 55–79. ISBN 978-0-08-100970-3. KOHLI, Rajiv a MITTAL, K. (ed.). Developments in surface contamination and cleaning: fundamentals and applied aspects . 12. Oxford, UK: Elsevier, 2019. ISBN 978-0-8155-1555-5. ÇOPUR, Mehmet. Optimization of dissolution of Zn and Cd metals from Waelz sintering waste by in aqueous (NH4)2SO4 solution. online. Energy Education Science and Technology Part A: Energy Science and Research . 2010, issue 25, s. 17–29. Available from: https://www.researchgate.net/publication/287849567_Optimization_of_dissolution_of_Zn_and_Cd_metals_from_Waelz_sintering_waste_by_in_aqueous_NH_4_2SO_4_solution . [cit. 2025-05-16]. DERAKHSHANI, Aliakbar; GHADI, Arezoo a VAHDAT, Seyed. Study of the effect of calcium nitrate, calcium formate, triethanolamine, and triisopropanolamine on compressive strength of Portland-pozzolana cement. online. Case Studies in Construction Materials . 2023, issue 18, s. 01799. ISSN 2214–5095. Available from: https://doi.org/10.1016/j.cscm.2022.e01799 . [cit. 2025-08-23]. WANG, Yimu; JIA, Jinqing; CAO, Qi a GAO, Xing. Effect of calcium formate on the compressive strength, and hydration process of cement composite containing fly ash and slag. online. Journal of Building Engineering . 2022, issue 50, s. 104133. ISSN 2352–7102. Available from: https://doi.org/10.1016/j.jobe.2022.104133 . [cit. 2025-08-23]. PîRVAN, Adrian-Alexandru; LOTHENBACH, Barbara; SCHRÖDER, Miriam; SCHWENDINGER, Michael; YAMMINE-MALESYS, Joumana et al. Enhancing slag reaction in cement blends using calcium formate and sodium metasilicate activators. online. Cement and Concrete Composites . 2025, issue 164, s. 106215. ISSN 0958–9465. Available from: https://doi.org/10.1016/j.cemconcomp.2025.106215 . [cit. 2025-08-23]. XU, Wenbin; LI, Qianlong a HARUNA, Sada. The Effect of Calcium Formate, Sodium Sulfate, and Cement Clinker on Engineering Properties of Fly Ash-Based Cemented Tailings Backfill. online. Advances in Materials Science and Engineering . 2019, issue 2019, s. 1–12. ISSN 1687–8434. Available from: https://doi.org/10.1155/2019/5370360 . [cit. 2025-08-23]. REN, Guosheng; TIAN, Zhijie; WU, Jingjiang a GAO, Xiaojian. Effects of combined accelerating admixtures on mechanical strength and microstructure of cement mortar. online. Construction and Building Materials . 2021, issue 304, s. 124642. ISSN 0950 – 0618. Available from: https://doi.org/10.1016/j.conbuildmat.2021.124642 . [cit. 2025-08-23]. GENG, Chaohui. THE EFFECT OF CALCIUM FORMATE ON THE PERFORMANCE OF SUPERSULFATED CEMENT. online. Ceramics - Silikaty . 2024, s. 216–224. ISSN 1804–5847. Available from: https://doi.org/10.13168/cs.2024.0021 . [cit. 2025-08-23]. ŠVEC, Jiří; ŠILER, Pavel; MÁSILKO, Jiří; NOVOTNÝ, Radoslav; KOPLÍK, Jan et al. Simultaneous thermogravimetric and differential thermal analysis determination of products formed during hydration of blended Portland cement doped with zinc. Journal of Thermal Analysis and Calorimetry . 2020, issue 142, č. 5, s. 1749–1758. ISSN 1388–6150. Available from: https://doi.org/10.1007/s10973-020-10253-5 . MURZYN, Paweł; MALATA, Grzegorz; WIśNIEWSKA, Joanna; KAPELUSZNA, Ewa a NOCUń-WCZELIK, Wiesława. Characterization of 40-year-old calcium silicate pastes by thermal methods and other techniques. Journal of Thermal Analysis and Calorimetry . 2019, issue 138, č. 6, s. 4271–4278. ISSN 1388–6150. Available from: https://doi.org/10.1007/s10973-019-08519-8 . ALARCON-RUIZ, Lucia; PLATRET, Gerard; MASSIEU, Etienne a EHRLACHER, Alain. The use of thermal analysis in assessing the effect of temperature on a cement paste. Cement and Concrete Research . 2005, issue 35, č. 3, s. 609–613. ISSN 00088846. Available from: https://doi.org/10.1016/j.cemconres.2004.06.015 . ZHOU, Q. a GLASSER, F.P. Thermal stability and decomposition mechanisms of ettringite at < 120°C. Cement and Concrete Research . 2001, issue 31, č. 9, s. 1333–1339. ISSN 00088846. Available from: https://doi.org/10.1016/S0008-8846(01)00558-0 . JO, Dweck; LEONARDO, Rosangela; CARTLEDGE, Frank; REALES, Oscar a TOLEDO FILHO, Romildo. Gypsum content determination in Portland cements by thermogravimetry. Journal of Thermal Analysis and Calorimetry . 2016, issue 123, č. 2, s. 1053–1062. ISSN 1388–6150. Available from: https://doi.org/10.1007/s10973-015-5078-y . ZAJAC, Maciej; ROSSBERG, Anne; LE SAOUT, Gwenn a LOTHENBACH, Barbara. Influence of limestone and anhydrite on the hydration of Portland cements. Cement and Concrete Composites . 2014, issue 46, s. 99–108. ISSN 09589465. Available from: https://doi.org/10.1016/j.cemconcomp.2013.11.007 . CHAUNSALI, Piyush a MONDAL, Paramita. Influence of Mineral Admixtures on Early-Age Behavior of Calcium Sulfoaluminate Cement. ACI Materials Journal . 2015, issue 112, č. 1. ISSN 0889-325X. Available from: https://doi.org/10.14359/51687240 . COLLIER, Nick C. TRANSITION AND DECOMPOSITION TEMPERATURES OF CEMENT PHASES - A COLLECTION OF THERMAL ANALYSIS DATA. online. Ceramics - Silikaty . 2016, issue 60, č. 4, s. 338–343. ISSN 1804–5847. Available from: https://doi.org/10.13168/cs.2016.0050 . [cit. 2025-12-18]. SNELLINGS, Ruben; CHWAST, Jacek; CIZER, Özlem; DE BELIE, Nele; DHANDAPANI, Yuvaraj et al. Report of TC 238-SCM: hydration stoppage methods for phase assemblage studies of blended cements—results of a round robin test. Materials and Structures . 2018, issue 51, č. 4. ISSN 1359–5997. Available from: https://doi.org/10.1617/s11527-018-1237-5 . MITCHELL, L. a MARGESON, J. The effects of solvents on C–S–H as determined by thermal analysis. Journal of Thermal Analysis and Calorimetry . 2006, issue 86, č. 3, s. 591–594. ISSN 1388–6150. Available from: https://doi.org/10.1007/s10973-006-7712-1 . HAWLETT, Peter C. Lea's Chemistry of Cement and Concrete . 4th. Elsevier Science & Technology Books, 2004. ISBN 978-0-7506-6256-7. PHROMPET, Chaiwat; SRIWONG, Chaval a RUTTANAPUN, Chesta. Mechanical, dielectric, thermal and antibacterial properties of reduced graphene oxide (rGO)-nanosized C3AH6 cement nanocomposites for smart cement-based materials. online. Composites Part B: Engineering . 2019, issue 175. ISSN 13598368. Available from: https://doi.org/10.1016/j.compositesb.2019.107128 . [cit. 2025-06-26]. Additional Declarations No competing interests reported. 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Šiler","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAAuUlEQVRIiWNgGAWjYDACZuYGBoYKOQYDErQwArWcMYZoOUCcHqAWxjZStMi3MzY+rpxnIG/OwGMm/YHBzp6gFoPDjM2GZ7cZGO5s4DGTOMCQzExYCzNjm2Tjtj8JBgfY0oBaDrARdlgzY/vPxjkGcC08hD1zmLGNsbEBpIX5GEiLBFF+kWw4ZmC44TDzYYszBsmE40e+//DBjw01BvIGxxsbb1RUEBFiCAAOKhLSwCgYBaNgFIwCPAAApfo1LaBwjbIAAAAASUVORK5CYII=","orcid":"","institution":"Brno University of Technology","correspondingAuthor":true,"prefix":"","firstName":"Pavel","middleName":"","lastName":"Šiler","suffix":""},{"id":595225822,"identity":"9dbbe81b-68cf-469a-a397-0408a087b1cd","order_by":1,"name":"Lukáš Matějka","email":"","orcid":"","institution":"Brno University of Technology","correspondingAuthor":false,"prefix":"","firstName":"Lukáš","middleName":"","lastName":"Matějka","suffix":""},{"id":595225823,"identity":"910bdd1e-b4c0-4daf-90be-83bc0c3eeddf","order_by":2,"name":"Jiří Švec","email":"","orcid":"","institution":"Brno University of Technology","correspondingAuthor":false,"prefix":"","firstName":"Jiří","middleName":"","lastName":"Švec","suffix":""},{"id":595225824,"identity":"96d39883-2a3d-4c44-8bbc-8439722f5f52","order_by":3,"name":"Jiří Másilko","email":"","orcid":"","institution":"Brno University of Technology","correspondingAuthor":false,"prefix":"","firstName":"Jiří","middleName":"","lastName":"Másilko","suffix":""},{"id":595225825,"identity":"c8632955-e5a0-4fe1-ac14-15ae28d1ce37","order_by":4,"name":"Vojtěch Florian","email":"","orcid":"","institution":"Brno University of Technology","correspondingAuthor":false,"prefix":"","firstName":"Vojtěch","middleName":"","lastName":"Florian","suffix":""},{"id":595225826,"identity":"ba5ba2f6-dfbe-4c13-9ec6-e4f779b2357b","order_by":5,"name":"Ondřej Kunovský","email":"","orcid":"","institution":"Brno University of 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Technology","correspondingAuthor":false,"prefix":"","firstName":"Radoslav","middleName":"","lastName":"Novotný","suffix":""},{"id":595225830,"identity":"4a7420bf-a0bd-473c-b480-72fd76eeaaaa","order_by":9,"name":"František Šoukal","email":"","orcid":"","institution":"Brno University of Technology","correspondingAuthor":false,"prefix":"","firstName":"František","middleName":"","lastName":"Šoukal","suffix":""}],"badges":[],"createdAt":"2025-12-27 09:08:13","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-8459865/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-8459865/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":103334419,"identity":"1c72f994-257e-4b75-9921-c4fa13401486","added_by":"auto","created_at":"2026-02-24 14:19:48","extension":"jpeg","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":326623,"visible":true,"origin":"","legend":"\u003cp\u003eCalorimetric curves of samples containing 1 % of Zinc as ZnO with HCOONa\u003c/p\u003e","description":"","filename":"floatimage1.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-8459865/v1/6303b92d6911432808a573bc.jpeg"},{"id":103334428,"identity":"c0591d65-93c5-40c0-88b4-b3b62abf043e","added_by":"auto","created_at":"2026-02-24 14:19:49","extension":"jpeg","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":324872,"visible":true,"origin":"","legend":"\u003cp\u003eCalorimetric curves of samples containing 1 % of Zinc as ZnO with HCOOK\u003c/p\u003e","description":"","filename":"floatimage2.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-8459865/v1/6aa8d12d145ace4bfa53a561.jpeg"},{"id":103334420,"identity":"d8fa2d22-4333-4e9c-84be-0b9bf30860f3","added_by":"auto","created_at":"2026-02-24 14:19:48","extension":"jpeg","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":322615,"visible":true,"origin":"","legend":"\u003cp\u003eCalorimetric curves of samples containing 1 % of Zinc as ZnO with (HCOO)\u003csub\u003e2\u003c/sub\u003eCa\u003c/p\u003e","description":"","filename":"floatimage3.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-8459865/v1/19a77f69121681a2966024ee.jpeg"},{"id":103334429,"identity":"9fd58c1a-594c-4e93-8fc1-5b2e9a8d97f4","added_by":"auto","created_at":"2026-02-24 14:19:49","extension":"jpeg","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":864415,"visible":true,"origin":"","legend":"\u003cp\u003eCalorimetric curves of samples containing 1 % of Zinc as ZnO with HCOOH\u003c/p\u003e","description":"","filename":"floatimage4.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-8459865/v1/05de16865ff8dc64a2025d9a.jpeg"},{"id":103506424,"identity":"b3b556f6-5b6f-48be-aea6-10d8cb13744f","added_by":"auto","created_at":"2026-02-26 13:36:17","extension":"png","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":86985,"visible":true,"origin":"","legend":"\u003cp\u003eCompressive strength of samples after 28 days of curing\u003c/p\u003e","description":"","filename":"floatimage5.png","url":"https://assets-eu.researchsquare.com/files/rs-8459865/v1/090b5a568053137788822d27.png"},{"id":103334425,"identity":"e0488973-6a64-415d-9faf-ab3919b9d880","added_by":"auto","created_at":"2026-02-24 14:19:49","extension":"jpeg","order_by":6,"title":"Figure 6","display":"","copyAsset":false,"role":"figure","size":322874,"visible":true,"origin":"","legend":"\u003cp\u003eTG-DTG curves of samples doped with HCOONa and (HCOO)\u003csub\u003e2\u003c/sub\u003eCa after 7 days of curing\u003c/p\u003e","description":"","filename":"floatimage6.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-8459865/v1/3a57abe280d5dac827c57a13.jpeg"},{"id":103506151,"identity":"ccf61ae8-921e-4e91-bbc5-ec3b6779d3a2","added_by":"auto","created_at":"2026-02-26 13:34:17","extension":"jpeg","order_by":7,"title":"Figure 7","display":"","copyAsset":false,"role":"figure","size":342891,"visible":true,"origin":"","legend":"\u003cp\u003eTG-DTG curves of samples doped with HCOONa and (HCOO)\u003csub\u003e2\u003c/sub\u003eCa after 28 days of curing\u003c/p\u003e","description":"","filename":"floatimage7.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-8459865/v1/816d4c2cdf146e24ffca300e.jpeg"},{"id":103506401,"identity":"1bb9a329-fbe2-406d-8e18-95408f4e3df9","added_by":"auto","created_at":"2026-02-26 13:36:04","extension":"jpeg","order_by":8,"title":"Figure 8","display":"","copyAsset":false,"role":"figure","size":336566,"visible":true,"origin":"","legend":"\u003cp\u003eTG-DTG curves of samples doped with 1 wt. % zinc and HCOONa or (HCOO)\u003csub\u003e2\u003c/sub\u003eCa after 7 days of curing\u003c/p\u003e","description":"","filename":"floatimage8.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-8459865/v1/533d8bf9612136aa3129e4ab.jpeg"},{"id":103334422,"identity":"21ee4417-037f-4274-9d62-e1d0e603ca22","added_by":"auto","created_at":"2026-02-24 14:19:48","extension":"jpeg","order_by":9,"title":"Figure 9","display":"","copyAsset":false,"role":"figure","size":339375,"visible":true,"origin":"","legend":"\u003cp\u003eTG-DTG curves of samples doped with 1 wt. % zinc and HCOONa or (HCOO)\u003csub\u003e2\u003c/sub\u003eCa after 28 days of curing\u003c/p\u003e","description":"","filename":"floatimage9.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-8459865/v1/df3d2ae101d86672d62a0fef.jpeg"},{"id":103505840,"identity":"c1758f01-8460-44a5-afd2-0c032c050f8e","added_by":"auto","created_at":"2026-02-26 13:33:12","extension":"jpeg","order_by":10,"title":"Figure 10","display":"","copyAsset":false,"role":"figure","size":312750,"visible":true,"origin":"","legend":"\u003cp\u003eTG-DTG curves of samples doped with 5 wt. % zinc and HCOONa or (HCOO)\u003csub\u003e2\u003c/sub\u003eCa after 7 days of curing\u003c/p\u003e","description":"","filename":"floatimage10.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-8459865/v1/8bec95a1af54aa9084aa9ea4.jpeg"},{"id":103334427,"identity":"ac166d27-dcc4-4079-ba8d-bf7393ad8df9","added_by":"auto","created_at":"2026-02-24 14:19:49","extension":"jpeg","order_by":11,"title":"Figure 11","display":"","copyAsset":false,"role":"figure","size":342645,"visible":true,"origin":"","legend":"\u003cp\u003eTG-DTG curves of samples doped with 5 wt. % zinc and HCOONa or (HCOO)\u003csub\u003e2\u003c/sub\u003eCa after 28 days of curing\u003c/p\u003e","description":"","filename":"floatimage11.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-8459865/v1/2c12f52a94c251e9e0d98b80.jpeg"},{"id":108007493,"identity":"4e1f201c-ab4b-4cc1-b353-2586cce17c94","added_by":"auto","created_at":"2026-04-28 13:00:14","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":4608236,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-8459865/v1/6d3fa80c-0851-4d0d-b029-e4e45e4fc0df.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Influence of formic acid and its salts on the elimination of the negative effect of zinc in portland cement","fulltext":[{"header":"1. Introduction","content":"\u003cp\u003ePortland cement, often combined with supplementary cementitious materials (SCMs) such as blast furnace slag and fly ash, is an extensively utilised binder for stabilising toxic wastes, including heavy metals. A key advantage of cementitious and pozzolanic binders lies in the high pH generated upon mixing with water. This alkaline environment facilitates the conversion of soluble metal compounds into sparingly soluble hydroxides. Furthermore, stabilisation with a cementitious matrix ensures the low leachability of these wastes [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eThe gel model provides a theoretical framework for understanding the effect of contaminants on hydration kinetics. This model posits the formation of a C-S-H gel membrane on the surface of silicate phase grains. This membrane permits the diffusion of water molecules towards the unhydrated core and the counter-diffusion of calcium and silicate ions into the solution. Diffusion across the C-S-H gel membrane is governed by the difference in osmotic potential across the membrane. The precipitation of portlandite from the solution and an excess of silicate anions leads to an increase in the osmotic pressure gradient, ultimately causing the rupture of the C-S-H gel membrane. This process is described as a periodically repeated cycle [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eAmong the many elements present in cement and SCMs that can adversely affect cement properties, zinc is particularly notable. Its primary sources include alternative fuels, such as tyres and other rubber products, and cement substitutes, namely metallurgical slags and fly ash. Zinc is widely recognised in cement industry research for its significant retardation of cement hydration and the resulting drastic reduction in early-age strengths. Zinc may be present either in a free form, as a constituent of specific clinker phases, or incorporated into a solid solution [\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eThe initial theoretical explanation for the retarding effect of zinc proposed the formation of an impermeable zinc hydroxide membrane on the surface of the hydrating phases. However, Arliguie [\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e] later suggested that while an impermeable layer may not be requisite for effective retardation, zinc significantly delays the nucleation of stable hydration products, such as C-S-H gel and portlandite. Grandet [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e], examining the clinker-solution interface in the presence of zinc, concluded that zinc hydrates precipitate before portlandite can be detected. Portlandite formation is only initiated when sufficient saturation with Ca\u003csup\u003e2+\u003c/sup\u003e and OH\u003csup\u003e\u0026minus;\u003c/sup\u003e ions is achieved. This strongly implies the consumption of these ions through the formation of zinc hydrates. This hypothesis is supported by Keppert [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e], whose microstructural analysis using SEM and XRD confirmed the presence of Zn as hydrates within the interparticle space, rather than being incorporated into the C-S-H gel structure. In contrast, Weeks [\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e], studying the use of zinc production slag as aggregate in OPC, found no evidence of zinc-containing layer formation on the surface of either clinker or slag particles. He further affirmed that portlandite is only confirmed in hydrated cement after the conclusion of the induction period.\u003c/p\u003e \u003cp\u003eThe formation of the insoluble phase Ca(Zn(OH)\u003csub\u003e3\u003c/sub\u003e)\u003csub\u003e2\u003c/sub\u003e\u0026sdot;2H\u003csub\u003e2\u003c/sub\u003eO leads to the depletion of Ca\u003csup\u003e2+\u003c/sup\u003e and OH\u003csup\u003e\u0026minus;\u003c/sup\u003e ions from the pore solution [\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e] [\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e]. Yousuf [\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e] confirmed the presence of this phase in ZnO-containing cement pastes through FTIR analysis. A high zinc content also retards C\u003csub\u003e3\u003c/sub\u003eA hydration, provided the SO\u003csub\u003e3\u003c/sub\u003e content in the system exceeds 2.5 wt. % [\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e]. The resultant reduction in the ion saturation of the pore solution suppresses the formation of C-S-H gel and portlandite. The findings of Ataie [\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e] on the retardation mechanism of OPC-ZnO hydration indicate a poisoning of the nucleation and growth of hydration products, which is consistent with the aforementioned principle of zinc retardation. The reactions culminating in the formation of Ca(Zn(OH)\u003csub\u003e3\u003c/sub\u003e)\u003csub\u003e2\u003c/sub\u003e\u0026sdot;2H\u003csub\u003e2\u003c/sub\u003eO are presented in Equations (\u003cspan refid=\"Equ1\" class=\"InternalRef\"\u003e1\u003c/span\u003e), (\u003cspan refid=\"Equ2\" class=\"InternalRef\"\u003e2\u003c/span\u003e), and (3) [\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e] [\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e] [\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e].\u003cdiv id=\"Equ1\" class=\"Equation\"\u003e\u003cdiv format=\"TEX\" class=\"mathdisplay\" id=\"FileID_Equ1\" name=\"EquationSource\"\u003e\n$$\\:{\\text{Z}\\text{n}}^{2+}+2\\:\\text{O}{\\text{H}}^{-}\\to\\:\\text{Z}\\text{n}{\\left(\\text{O}\\text{H}\\right)}_{2}$$\u003c/div\u003e\u003cdiv class=\"EquationNumber\"\u003e1\u003c/div\u003e\u003c/div\u003e\u003cdiv id=\"Equ2\" class=\"Equation\"\u003e\u003cdiv format=\"TEX\" class=\"mathdisplay\" id=\"FileID_Equ2\" name=\"EquationSource\"\u003e\n$$\\:\\text{Z}\\text{n}{\\left(\\text{O}\\text{H}\\right)}_{2}+2\\:\\text{O}{\\text{H}}^{-}\\to\\:\\text{Z}\\text{n}{\\text{O}}_{2}^{2-}+2\\:{\\text{H}}_{2}\\text{O}$$\u003c/div\u003e\u003cdiv class=\"EquationNumber\"\u003e2\u003c/div\u003e\u003c/div\u003e\u003cdiv id=\"Equ3\" class=\"Equation\"\u003e\u003cdiv format=\"TEX\" class=\"mathdisplay\" id=\"FileID_Equ3\" name=\"EquationSource\"\u003e\n$$\\:2\\:\\text{Z}\\text{n}{\\text{O}}_{2}^{2-}+{\\text{C}}_{3}\\text{S}/\\text{O}-\\text{C}{\\text{a}}^{2+}+6\\:{\\text{H}}_{2}\\text{O}\\to\\:{\\text{C}}_{3}\\text{S}/\\text{O}-\\text{C}\\text{a}{\\text{Z}\\text{n}}_{2}{\\left(\\text{O}\\text{H}\\right)}_{6}\\bullet\\:2{\\:\\text{H}}_{2}\\text{O}+2\\:{\\text{O}\\text{H}}^{-}$$\u003c/div\u003e\u003cdiv class=\"EquationNumber\"\u003e3\u003c/div\u003e\u003c/div\u003e\u003c/p\u003e \u003cp\u003eOuki and Hills [\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e] investigated the microstructure of cement blended with various salts and observed that the presence of zinc led to an increase in the amount of unreacted cement. The retardation or delay of setting is desirable in certain applications of cementitious materials, such as \u003cb\u003ehigh-\u003c/b\u003eperformance concrete (HPC). Since HPC preparation often involves blended cement, plasticisers, and other admixtures, there is potential for utilising zinc salts as targeted setting retarders. Li et al. [\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e] explored the effects of zinc chloride and sulphate on hydration and ultimate compressive strength.\u003c/p\u003e \u003cp\u003eLiu et al. [\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e] and Nochaiya et al. [\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e] discussed the impact of ZnO nanoparticles on the hydration, strength, and microstructure of cement pastes. Even the lowest dosage of nanoparticles was found to slow the cement setting, consequently reducing the early strength of the sample. However, after 3 days, the strengths of the samples with and without nanoparticles were comparable. Following 7 days of curing, the strengths of all nanoparticle-containing samples were higher than the reference. Calorimetric measurements indicated a slightly lower total heat of hydration when nanoparticles were used. The addition of nanoparticles also improved the pore size distribution, resulting in a more compact microstructure [\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e]. This strength increase is attributed to the pore-filling effect of the nanoparticles. In contrast, Liu et al. [\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e] reported the opposite outcome, where the final strength decreased with increasing nanoparticle content.\u003c/p\u003e \u003cp\u003eŠiler et al. [\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e] examined the effect of zinc in the form of ZnO, Zn(NO\u003csub\u003e3\u003c/sub\u003e)\u003csub\u003e2\u003c/sub\u003e, and ZnCl\u003csub\u003e2\u003c/sub\u003e on cement pastes, and in subsequent studies [\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e] [\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e], they introduced slag and fly ash into the same experimental setup. They determined that ZnO acts as the strongest retarder due to its low solubility. While ZnCl\u003csub\u003e2\u003c/sub\u003e accelerated hydration in the cement paste at a 1 wt. % addition, this acceleration was absent when combined with slag. Furthermore, a \u003cb\u003esynergistic\u003c/b\u003e retarding effect was observed when zinc was combined with slag. A 15 wt. % addition of fly ash to cement causes further retardation of hydration reactions, primarily through the consumption of Ca\u003csup\u003e2+\u003c/sup\u003e ions by the fly ash particles.\u003c/p\u003e \u003cp\u003eAccelerators are substances that, even in small quantities, speed up the hydration reactions of clinker phases and the formation of C-S-H gel. This leads to shorter setting times, faster development of early-age strengths, or both. They are employed, for example, to offset the effects of low temperatures or in mixtures with freezing point-lowering agents. Accelerators are also used in the production of precast concrete to facilitate faster demoulding, achieve a high-quality surface finish, or reduce curing time. However, the acceleration of hydration can potentially deteriorate the long-term mechanical properties and durability of the concrete. Consequently, alternative acceleration methods, such as optimising the cement composition or reducing the water-to-cement ratio, are preferred where feasible [\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e] [\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e] [\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e] [\u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eBased on their chemical composition, accelerators can be classified into:\u003c/p\u003e \u003cp\u003e \u003col\u003e \u003cspan\u003e \u003cli\u003e \u003cp\u003eSoluble inorganic salts of alkali and alkaline earth metals (Cl\u003csup\u003e\u0026minus;\u003c/sup\u003e, Br\u003csup\u003e\u0026minus;\u003c/sup\u003e, F\u003csup\u003e\u0026minus;\u003c/sup\u003e, I\u003csup\u003e\u0026minus;\u003c/sup\u003e, ClO\u003csub\u003e4\u003c/sub\u003e\u003csup\u003e\u0026minus;\u003c/sup\u003e, CO\u003csub\u003e3\u003c/sub\u003e\u003csup\u003e2\u0026minus;\u003c/sup\u003e, SCN\u003csup\u003e\u0026minus;\u003c/sup\u003e, SO\u003csub\u003e4\u003c/sub\u003e\u003csup\u003e2\u0026minus;\u003c/sup\u003e, S\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e3\u003c/sub\u003e\u003csup\u003e2\u0026minus;\u003c/sup\u003e, NO\u003csub\u003e2\u003c/sub\u003e\u003csup\u003e\u0026minus;\u003c/sup\u003e, NO\u003csub\u003e3\u003c/sub\u003e\u003csup\u003e\u0026minus;\u003c/sup\u003e, SiO\u003csub\u003e4\u003c/sub\u003e\u003csup\u003e2\u0026minus;\u003c/sup\u003e, Al(OH)\u003csub\u003e4\u003c/sub\u003e\u003csup\u003e\u0026minus;\u003c/sup\u003e, OH\u003csup\u003e\u0026minus;\u003c/sup\u003e).\u003c/p\u003e \u003c/li\u003e \u003c/span\u003e \u003cspan\u003e \u003cli\u003e \u003cp\u003eWater-soluble organic compounds (e.g., triethanolamine (TEA) or calcium salts of lower organic acids such as formate, acetate, propionate, and butyrate)\u003c/p\u003e \u003c/li\u003e \u003c/span\u003e \u003c/ol\u003e \u003c/p\u003e \u003cp\u003eThe efficiency of an accelerator depends on both the anion and the cation. Cations and anions can be organised into series based on their effectiveness in accelerating C\u003csub\u003e3\u003c/sub\u003eS hydration, with butyrate being reported as the most efficient [\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e] [\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e] [\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e] [\u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eMatějka et al. [\u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e] investigated the influence of thiocyanate-based accelerators (NaSCN and KSCN) on zinc-doped cement and found that they further retarded the setting of the contaminated cement. In a separate study, Matějka et al. [\u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e] explored the effect of nitrate-based accelerators on zinc-doped cement. They concluded that all tested additives effectively reduced the setting time without compromising mechanical properties. The commercial accelerators were found to be significantly less effective than the pure nitrates, a result attributed to their complex composition and the dosage being optimised for different cement systems.\u003c/p\u003e \u003cp\u003eFormate salts were introduced as setting accelerators in the latter half of the nineteenth century, primarily to counteract the retarding effects of water-reducing additives. Evidence suggests that calcium formate promotes the formation of ettringite and certain AFm phases that precipitate from the hydration of C\u003csub\u003e3\u003c/sub\u003eA in the presence of gypsum. Singh et al. [\u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e] hypothesised that calcium formate accelerates the hydration of C\u003csub\u003e4\u003c/sub\u003eAF in oilwell cement by forming Fe\u003csup\u003e3+\u003c/sup\u003e-formate complexes, which exhibit higher solubility than other Fe\u003csup\u003e3+\u003c/sup\u003e hydrates. This mechanism is thought to disrupt the formation of any barrier layer on the surface of C\u003csub\u003e4\u003c/sub\u003eAF grains [\u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eThe hydration of alite is also reportedly accelerated by calcium formate addition, which promotes C-S-H gel formation and increases the overall content of chemically bound water. There appears to be a maximum optimal dosage of this compound, typically around 2 wt. % relative to cement, though this is dependent on the specific cement used. The optimal dose is also highly contingent on the presence of SCMs. For instance, pre-blending the cement with 40 wt. % fly ash was found to reduce the effectiveness of calcium formate in accelerating setting [\u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e30\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eSingh et al. [\u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e] offered a hypothesis to explain the mechanism of action of formate salts, proposing that formate anions adsorb onto the surface of C\u003csub\u003e3\u003c/sub\u003eS and create an easily rupturable layer. The continuous disruption of this layer promotes further hydration by enhancing the diffusion of water to the hydrating cement grain. A similar mechanism was proposed by Heikal et al. [\u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e31\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eCalcium formate also influences the morphology of cement hydration products. Low doses of calcium formate resulted in the precipitation of small, compact, needle-like C-S-H gel crystals, while higher doses yielded bent-needle-like structures. The crystal size of ettringite also decreased, contributing to a more compact binder structure. The addition of a small dose of calcium formate, approximately 0.75 wt. %, was shown to reduce setting time by 30%, primarily by refining the pore structure [\u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e32\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eThe capacity of formate salts to accelerate setting and improve compressive strength appears to correlate with the C\u003csub\u003e3\u003c/sub\u003eA content of the cement. Levitt [\u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e33\u003c/span\u003e] investigated the development of cement paste doped with calcium formate using three different cements with C\u003csub\u003e3\u003c/sub\u003eA content ranging from 3 wt. % to 14 wt. %. The effectiveness of this compound in improving mechanical properties was observed to decrease with increasing C\u003csub\u003e3\u003c/sub\u003eA content. Furthermore, the efficacy in enhancing mechanical properties was greater when the C\u003csub\u003e3\u003c/sub\u003eA/SO\u003csub\u003e3\u003c/sub\u003e ratio exceeded 4, suggesting a preference for the formation of Fe\u003csup\u003e3+\u003c/sup\u003e complexes before adsorption onto hydrating C\u003csub\u003e3\u003c/sub\u003eS [\u003cspan citationid=\"CR34\" class=\"CitationRef\"\u003e34\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eThe increasing presence of zinc in cementitious systems constitutes a significant problem requiring effective mitigation strategies. While the effect of zinc in cement has been described in numerous publications, a universally effective method to eliminate its negative effects has yet to be fully established. This article is primarily aimed at demonstrating a potential pathway to mitigate zinc's adverse effect on hydration while simultaneously enhancing the properties of the resulting material. Furthermore, it incorporates information designed to foster a deeper understanding of the mechanism of zinc action in cement and the potential utility of accelerators based on formic acid and its salts.\u003c/p\u003e"},{"header":"2. Material and samples preparation","content":"\u003cp\u003eFormic acid salts were synthesised by neutralising formic acid p.a. purity with either Ca(OH)\u003csub\u003e2\u003c/sub\u003e, NaOH or KOH. The purity of synthesised salts was confirmed using XRD analysis. The potassium formate was not used for further experiments due to difficulties with storage and preparing the samples. This compound exhibits a very high level of hygroscopicity. This caused the salt to dissolve in atmospheric moisture during the preparation of the samples, which caused inconsistencies in dosage and water-to-cement ratio.\u003c/p\u003e \u003cp\u003eThe research involved formulating cement matrices using a commercially sourced Ordinary Portland Cement (OPC) designated CEM I 42.5 R. This binder was procured from Mokr\u0026aacute;-Českomoravsk\u0026yacute; cement, a.s. (Heidelberg Cement Czech Republic). The complete chemical profile of this cement is delineated in Table\u0026nbsp;\u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e3\u003c/span\u003e. All test compositions were batched with a constant water-to-cement ratio (w/c) of 0.4. The specific proportions and component quantities for each mix are summarised in Table\u0026nbsp;\u003cspan refid=\"Tab4\" class=\"InternalRef\"\u003e4\u003c/span\u003e.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eComposition of the OPC used in the samples.\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"2\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eCement (%)\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCaO\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e63.20\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSiO\u003csub\u003e2\u003c/sub\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e19.50\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAl\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e3\u003c/sub\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e4.70\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eFe\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e3\u003c/sub\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e3.30\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eMgO\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e1.50\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSO\u003csub\u003e3\u003c/sub\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e3.07\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCl\u003csup\u003e\u0026minus;\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e0.066\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eK\u003csub\u003e2\u003c/sub\u003eO\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e0.78\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eNa\u003csub\u003e2\u003c/sub\u003eO\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e0.15\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eInsoluble\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e0.67\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eLOI\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e3.38\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab2\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 2\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eComposition of samples doped with formates and formic acid for calorimetry\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"6\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e \u003cp\u003eComponent\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eCEM (g)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eH\u003csub\u003e2\u003c/sub\u003eO (g)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003eZnO (g)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c6\"\u003e \u003cp\u003eAdditive (g)\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e \u003cp\u003eRef. CEM I\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e250\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e100\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e \u003cp\u003eRef. CEM I\u0026thinsp;+\u0026thinsp;1% Zn\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e250\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e100\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e6.20\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e \u003cp\u003eRef. CEM I\u0026thinsp;+\u0026thinsp;5% Zn\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e250\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e100\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e31.10\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\" morerows=\"3\" rowspan=\"4\"\u003e \u003cp\u003eHCOONa\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1:0.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e500\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e200\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e6.20\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e2.6\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1:1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e500\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e200\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e6.20\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e5.2\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1:2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e500\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e200\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e6.20\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e10.4\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1:5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e500\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e200\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e6.20\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e26.0\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\" morerows=\"3\" rowspan=\"4\"\u003e \u003cp\u003eHCOOK\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1:0.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e500\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e200\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e6.20\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e3.20\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1:1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e500\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e200\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e6.20\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e6.40\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1:2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e500\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e200\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e6.20\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e12.90\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1:5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e500\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e200\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e6.20\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e32.20\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\" morerows=\"3\" rowspan=\"4\"\u003e \u003cp\u003e(HCOO)\u003csub\u003e2\u003c/sub\u003eCa\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1:0.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e500\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e200\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e6.20\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e5.00\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1:1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e500\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e200\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e6.20\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e9.90\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1:2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e500\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e200\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e6.20\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e19.90\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1:5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e500\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e200\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e6.20\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e49.70\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\" morerows=\"3\" rowspan=\"4\"\u003e \u003cp\u003eHCOOH\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1:0.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e500\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e200\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e6.20\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e1.80\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1:1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e500\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e200\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e6.20\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e3.50\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1:2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e500\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e200\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e6.20\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e7.00\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1:5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e500\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e200\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e6.20\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e17.60\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003eTo study the influence of metal ions, every formulation was systematically spiked with ZnO powder. The ZnO quantity was precisely calculated to introduce 1 wt. % and 5 wt. % elemental zinc into the dry mass of the cement. Accelerator dosages were referenced using a molar equivalent basis relative to the lower 1 wt. % zinc loading.\u003c/p\u003e \u003cp\u003eThe mixing regimen commenced by thoroughly blending the cement with all powdered additives through initial manual agitation. This dry mix was then subjected to 30 seconds of mechanical agitation at a low speed using a benchtop mixer. Following this, the mixing water, which contained the pre\u0026thinsp;\u0026minus;\u0026thinsp;dissolved accelerator, was introduced, and the resulting slurry was homogenised for an additional 30 seconds at high speed. A one-minute (60 s) pause ensued, during which the bowl's interior was manually scraped to ensure full material inclusion and uniform consistency. The final mixing phase consisted of 120 seconds of high-speed mixing.\u003c/p\u003e \u003cp\u003eThe freshly prepared cement paste was subsequently cast into the appropriate vessels\u0026mdash;be they moulds, measuring cells, or storage containers\u0026mdash;according to the requirements of the planned investigation. Specimens were maintained in a controlled high\u0026thinsp;\u0026minus;\u0026thinsp;humidity chamber until the designated testing ages of 7 or 28 days were reached.\u003c/p\u003e \u003cp\u003eFor thermal (TG-DTG) and X-ray diffraction (XRD) assessments, the hydration process within the cement paste had to be halted definitively. The protocol for storage and hydration termination was strictly followed, according to the established RILEM recommendations [\u003cspan citationid=\"CR35\" class=\"CitationRef\"\u003e35\u003c/span\u003e]. The set specimens were broken into small fragments and immediately submerged twice for 15 minutes in anhydrous isopropyl alcohol, followed by two 15-minute soakings in acetone to extract the pore water fully. After the solvent treatments, the fragments underwent drying at 40\u0026deg;C overnight to remove residual organic compounds. They were then stored over silica gel to prevent any subsequent moisture uptake [\u003cspan citationid=\"CR35\" class=\"CitationRef\"\u003e35\u003c/span\u003e].\u003c/p\u003e"},{"header":"3. Experimental methods","content":"\u003cp\u003e \u003cem\u003eCalorimetry\u003c/em\u003e \u003c/p\u003e \u003cp\u003eCalorimetry technique was deployed to track the influence of zinc on the hydration progression and allows monitor overall material response in a practical setting [\u003cspan citationid=\"CR36\" class=\"CitationRef\"\u003e36\u003c/span\u003e]. Managing and predicting the thermal peak generated by the hydration reaction is paramount for massive concrete pours. Isoperibolic calorimetry has proven to be a suitable method for studying the effect of zinc on cement [\u003cspan citationid=\"CR37\" class=\"CitationRef\"\u003e37\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eIsoperibolic calorimetry is a frequent choice for tracking the thermal development during the reaction of cementitious binders [\u003cspan citationid=\"CR38\" class=\"CitationRef\"\u003e38\u003c/span\u003e] [\u003cspan citationid=\"CR39\" class=\"CitationRef\"\u003e39\u003c/span\u003e] [\u003cspan citationid=\"CR40\" class=\"CitationRef\"\u003e40\u003c/span\u003e]. The underlying principle entails measuring the sample's internal temperature fluctuations while its surroundings are held at a stable temperature. The cumulative heat release is ascertained via post\u0026thinsp;\u0026minus;\u0026thinsp;test numerical integration of the temperature data, using calibration factors for the apparatus [\u003cspan citationid=\"CR36\" class=\"CitationRef\"\u003e36\u003c/span\u003e]. Since the sample temperature naturally increases due to the exothermic hydration reaction (reflecting practical conditions), combining this approach with the isothermal method offers a comprehensive view of the reaction mechanisms [\u003cspan citationid=\"CR36\" class=\"CitationRef\"\u003e36\u003c/span\u003e].)\u003c/p\u003e \u003cp\u003eX\u0026thinsp;\u0026minus;\u0026thinsp;ray Diffraction (XRD) represents a non-destructive method commonly used for the analysis of crystallised substances. The resultant X-ray diffractogram furnishes characteristic structural information, which is key to both the identification and absolute quantification of the various crystalline phases present in the matrix [\u003cspan citationid=\"CR41\" class=\"CitationRef\"\u003e41\u003c/span\u003e] [\u003cspan citationid=\"CR42\" class=\"CitationRef\"\u003e42\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eThe X\u0026thinsp;\u0026minus;\u0026thinsp;ray crystallographic analysis was performed on an Empyrean X-Ray diffractometer (Malvern Panalytical, Royston, UK). The instrument employed Bragg\u0026ndash;Brentano parafocusing geometry and CuKα radiation. Data were collected across a 2θ range extending from 5∘ to 120∘, using an angular increment of 0.013∘2θ and a 25-second signal acquisition time per step. Automated divergence slits were utilised to maintain a constant area of specimen exposure. To optimise the signal quality, four individual scans were recorded and mathematically summed.\u003c/p\u003e"},{"header":"4. Result and discussion","content":"\u003cp\u003e \u003cem\u003eThe effects of formic acid and formates \u0026ndash; Isoperibolic calorimetry\u003c/em\u003e \u003c/p\u003e \u003cp\u003eThe calorimetric measurements of cement-ZnO samples doped with HCOONa are presented in Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e. Even low doses of HCOONa accelerated the setting of these samples. The induction period decreased with increasing doses up to about 50 h for the highest dose. This shows that sodium formate has comparable effectiveness to nitrate-based accelerators [\u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e]. There appears to be a linear correlation between setting time, maximum temperature and dose up to a 1:2 ratio of additives. Even though the doses are doubled in each sample, the difference in setting time between each sample is roughly the same. This points to the optimal effective dose being the 1:2 ratio of this additive.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eThe setting of cement-ZnO samples doped with HCOOK is presented in Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e. The behaviour of these samples was very similar to that of previous samples doped with HCOONa, which is to be expected. Potassium salts generally have lower performance as accelerators due to increased heating during mixing and increased porosity [\u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e32\u003c/span\u003e]. Higher alkali content harms the stability of ettringite and mechanical properties, depending on the composition of the used cement.\u003c/p\u003e \u003cp\u003eThe total evolved heat of both alkali salts follows a similar trend. The samples with lower doses of HCOONa or HCOOK showed slightly lower total evolved heat compared to pure cement and cement with ZnO. This indicates a slightly lower overall hydration degree, even with accelerated hydration. The sample with a 1:2 ratio of additives in both types of samples exhibited comparable total evolved heat to both references.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eCompared to alkali formate salts, calcium formates caused significant acceleration of setting even at the lowest dose. The lowest dose of calcium formate reduced setting time to around 60 h, comparable to the highest doses of HCOONa and HCOOK, as seen in Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e. The most effective dose appears to be a 1:2 ratio of zinc to accelerator. Increasing the dose beyond this ratio caused a change in the hydration mechanism. The largest dose of calcium formate caused a visible increase in the first hydration peak and a decrease in the height of the main hydration peak. This indicates an effective limit to how much calcium formate can be used relative to the cement and zinc contaminant amount before any detrimental effects.\u003c/p\u003e \u003cp\u003eThe samples containing 1 : 0,5 to 2 show a clear increase in total evolved heat, indicating a higher hydration degree than the reference cement. The sample with the highest dose of calcium formate had significantly lower total evolved heat, which correlates with lower hydration degree and retarded setting. This indicates the maximum effective dose of this compound for accelerating the setting of the cement-ZnO system.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eA set of samples of the cement-ZnO system doped with formic acid was prepared to investigate the effect of HCOO\u003csup\u003e\u0026minus;\u003c/sup\u003e. Results of these samples are presented in Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e. Here, it is apparent that low doses of formic acid retard setting, but higher doses accelerate setting. An acidic accelerator is not comparable to salts due to the drastically different pH of the pore solution. A low pH environment leaches cations from cement phases, drastically affecting the solubility of ZnO in the pore solution. Zinc oxide is an amphoteric compound. In low pH environments, it dissolves into free Zn\u003csup\u003e2+\u003c/sup\u003e that can be incorporated into various phases. In contrast, it forms various Zn(OH)\u003csub\u003ex\u003c/sub\u003e\u003csup\u003ey\u0026minus;\u003c/sup\u003e species in high pH that precipitate out of the pore solution, depleting calcium ions [\u003cspan citationid=\"CR43\" class=\"CitationRef\"\u003e43\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eWhile a low pH environment retards the setting of OPC, it dissolves ions into the pore solution, promoting the formation of hydration products and thus increasing the hydration degree of cement phases. That can result in an improvement of mechanical properties and a decrease in the overall porosity of the structure. This effect can be seen from the graph showcasing cumulative heat release during the calorimetric measurements. Only the lowest dose of HCOOH caused further retardation of setting and a decrease in cumulative heat, thus hydration degree. The second lowest dose did not noticeably affect the setting but slightly increased the hydration degree. The two highest doses of formic acid caused an acceleration of setting and higher released cumulative heat that references OPC.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003e \u003cem\u003eThe effects of formates \u0026ndash; Mechanical properties\u003c/em\u003e \u003c/p\u003e \u003cp\u003eThe graph presented in Fig.\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003e shows the compressive strength of samples doped with formate salts and formic acid after 28 days of curing. Formic acid had a negative influence on compressive strength in most doses, which correlates with the results of calorimetric measurements, where low doses retarded setting. The hydration of ZnO-cement was accelerated only in very high doses. The lowest dose of salts did not noticeably impact the mechanical properties of the samples. The sodium and calcium salt slightly improved compressive strength compared to the reference CEM I and reference CEM I with ZnO. Both sodium and calcium formates effectively reduced the setting time, even at lower doses.\u003c/p\u003e \u003cp\u003eThe improvement of compressive strength by the addition of calcium formate confirms results in available publications. Calcium formate improves both early and late-stage mechanical properties by promoting the formation of C-S-H gel, combined water content and decreasing porosity. This improvement was demonstrated not only in OPC paste but also in mortars containing various SCMs, such as condensed silica fume, ground clay bricks, fly ash and GGBFS. Calcium formate salts were also very effective in supersulfonated cement with very high GGBFS content [\u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e31\u003c/span\u003e] [\u003cspan citationid=\"CR44\" class=\"CitationRef\"\u003e44\u003c/span\u003e] [\u003cspan citationid=\"CR45\" class=\"CitationRef\"\u003e45\u003c/span\u003e] [\u003cspan citationid=\"CR46\" class=\"CitationRef\"\u003e46\u003c/span\u003e] [\u003cspan citationid=\"CR47\" class=\"CitationRef\"\u003e47\u003c/span\u003e] [\u003cspan citationid=\"CR48\" class=\"CitationRef\"\u003e48\u003c/span\u003e] [\u003cspan citationid=\"CR49\" class=\"CitationRef\"\u003e49\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eSamples with potassium formate showed lower compressive strength than the other accelerated samples, but were comparable to the reference CEM I. This could be caused by a similar effect as KSCN [\u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e]. With increasing doses, the mechanical properties of samples doped with sodium and calcium formate improved to the second-highest dose. The compressive strength of the potassium formate-doped samples was comparable with the measurement error. The highest dose of all salts induced a small decrease in compressive strength, but not lower than the reference CEM I.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003e \u003cem\u003eThe effects of formates \u0026ndash; TG-DTG\u003c/em\u003e \u003c/p\u003e \u003cp\u003eThe TG-DTG analysis was performed on samples containing 0, 1 and 5 wt. % of zinc. Zinc-free samples were analysed to compare phase composition differences caused by the presence of zinc ions. The high zinc content samples were prepared to determine the presence of zinc-containing phases. The doses of accelerators were chosen based on the results of isoperibolic calorimetry and experience with other additives studied in our other papers [\u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e] [\u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e]. These doses were a 1:1 ratio of zinc to additive (Min dose) and a 1:5 ratio of zinc to additive (Max dose).\u003c/p\u003e \u003cp\u003eThe TG-DTG analysis of samples without zinc after 7 days of curing is presented in Fig.\u0026nbsp;\u003cspan refid=\"Fig6\" class=\"InternalRef\"\u003e6\u003c/span\u003e. The biggest difference between the samples doped with sodium and calcium formate is in the height of the decomposition peaks at around 120\u0026deg;C, 160\u0026deg;C and overall mass loss. The decomposition peak at around 120\u0026deg;C can be attributed to C-S-H gel [\u003cspan citationid=\"CR50\" class=\"CitationRef\"\u003e50\u003c/span\u003e]. The sodium formate-doped samples showed a lower amount of these hydration products and a slight shift of this peak to the right, after 7 days of curing, compared to pure OPC. This points to a more amorphous structure of hydration products and a lower hydration degree, as seen from the slightly lower total mass loss. One of the possible explanations as to why this sample is less hydrated even when the accelerator was added is a drastic increase in the alkali content of the pore solution. It appears that when contamination is not present, sodium formate is not a very effective accelerator, which could explain why sodium formate is not widely used compared to sodium nitrate. The height of the portlandite decomposition peak at around 420\u0026deg;C [\u003cspan citationid=\"CR51\" class=\"CitationRef\"\u003e51\u003c/span\u003e] was comparable to that of the reference samples in both samples. This means that the silicate phases are not less hydrated, but the composition of the hydration products is different.\u003c/p\u003e \u003cp\u003eDifferent composition of the hydration products is visible from the significantly lower decomposition peak of ettringite at around 160\u0026ndash;170\u0026deg;C [\u003cspan citationid=\"CR52\" class=\"CitationRef\"\u003e52\u003c/span\u003e] [\u003cspan citationid=\"CR53\" class=\"CitationRef\"\u003e53\u003c/span\u003e]. The detrimental effect of high alkali content on the formation and stability of ettringite and monosulphate was mentioned in paper [\u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eThe significant increase in carbonate content, as can be seen from decomposition peaks between 600 and 800\u0026deg;C, is most likely the result of higher carbonation caused by increased alkali content of the pore solution [\u003cspan citationid=\"CR54\" class=\"CitationRef\"\u003e54\u003c/span\u003e] [\u003cspan citationid=\"CR55\" class=\"CitationRef\"\u003e55\u003c/span\u003e] [\u003cspan citationid=\"CR56\" class=\"CitationRef\"\u003e56\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eThe calcium formate appears to be a generally effective hydration accelerator, as seen from the slightly higher mass loss of main hydration products compared to OPC. This salt also did not significantly impact the content of ettringite, which is important for accelerating the setting of zinc-contaminated cement. After 7 days of curing, these samples show a slightly higher amount of silicate hydration products and portlandite. The higher carbonate content in these samples can be explained by the higher carbonation of the samples due to the added soluble calcium ions in the pore solution.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eAfter 28 days of curing, as can be seen from Fig.\u0026nbsp;\u003cspan refid=\"Fig7\" class=\"InternalRef\"\u003e7\u003c/span\u003e, it is apparent that lower doses of HCOONa had a detrimental effect on hydration based on the lower silicate hydrate decomposition peak, lower portlandite decomposition peak and overall lower total mass loss. On the other hand, the higher dose caused a slight increase in silicate hydrate content but drastically lower Aft/AFm content. The total mass loss of the samples with a high amount of added HCOONa was comparable to that of the reference cement.\u003c/p\u003e \u003cp\u003eThese results could point to competing effects of Na\u003csup\u003e+\u003c/sup\u003e and HCOO\u003csup\u003e\u0026minus;\u003c/sup\u003eon hydration mechanisms. While increasing the alkali content of the pore solution destabilises ettringite and is detrimental to the hydration mechanism of OPC, increasing the content of formate ions promotes hydration of the silicate phase, counteracting the effects of Na\u003csup\u003e+\u003c/sup\u003e.\u003c/p\u003e \u003cp\u003eThe calcium formate-doped samples behaved very differently. The composition of these samples was very similar to the reference sample. The most important difference was the slightly higher silicate hydrate and portlandite content when a higher dose was used. This further confirms that this salt is an effective accelerator without significant negative side effects.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eThe zinc content in the system influences the cement's hydration mechanism and effectiveness. After 7 days of curing, the cement-ZnO samples doped by sodium formate, shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig8\" class=\"InternalRef\"\u003e8\u003c/span\u003e, had a higher mass loss of silicate hydrates but with significantly smaller and wider decomposition peaks. Along with the significantly higher portlandite decomposition peak, it shows that adding sodium formate caused an acceleration of hydration. This effect was seen in calorimetry results. Compared to the reference, the wider decomposition peak indicates the higher amorphous content of these samples. Increasing the dose of sodium formate caused an increase in the height of the silicate hydrate peak, confirming increased acceleration with increased dose. The increased height of the peak at around 170\u0026deg;C [\u003cspan citationid=\"CR55\" class=\"CitationRef\"\u003e55\u003c/span\u003e] [\u003cspan citationid=\"CR56\" class=\"CitationRef\"\u003e56\u003c/span\u003e] indicates a higher ettringite content than the reference sample. The decomposition peak at around 240\u0026deg;C was present in many previous samples containing sodium salts and indicates the presence of either a monocarbonate phase or another aluminate hydrate [\u003cspan citationid=\"CR57\" class=\"CitationRef\"\u003e57\u003c/span\u003e]. Both samples demonstrated noticeably higher total mass loss than the reference, which increased slightly with increased dose. This indicates a higher hydration degree.\u003c/p\u003e \u003cp\u003eThe calcium formate-containing samples exhibited higher C-S-H gel and ettringite decomposition peaks. Along with the higher decomposition peak of portlandite, this points to accelerated hydration and higher crystalline content than the sodium formate-doped samples.\u003c/p\u003e \u003cp\u003eThe lower portlandite content in the samples with higher doses of calcium formate can be explained by the significantly larger carbonatation of these samples, as seen from the significantly larger carbonate decomposition peak.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eThe TG-DTG analysis of the samples after 28 days of curing is presented in Fig.\u0026nbsp;\u003cspan refid=\"Fig9\" class=\"InternalRef\"\u003e9\u003c/span\u003e. The HCOONa-doped samples showed comparable content of C-S-H gel and silicate hydrates to the reference sample in the case of the smaller dose. The sample with a higher dose showed a higher content of silicate hydrates but with less crystalline structure, as is evident from the shift of the 120\u0026deg;C decomposition peak to the right [\u003cspan citationid=\"CR58\" class=\"CitationRef\"\u003e58\u003c/span\u003e] [\u003cspan citationid=\"CR59\" class=\"CitationRef\"\u003e59\u003c/span\u003e]. The content of ettringite did not significantly increase between measurements, with its content decreasing with increased dose. The decrease in ettringite content with increasing alkali content was discussed in our previous published work Matejka et al [\u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e]. The height of the portlandite decomposition peak seems to increase slightly with increasing doses of sodium formate, confirming increased hydration acceleration.\u003c/p\u003e \u003cp\u003eThe overall mass loss increased with an increased dose of this additive, but it is slightly lower than the total mass of the reference. This shows that while the setting is accelerated, as was seen in the calorimetry results, the content of some hydration products is increased at the expense of others.\u003c/p\u003e \u003cp\u003eThe samples doped with Ca(HCOO)\u003csub\u003e2\u003c/sub\u003e showed a comparable amount of silicate hydration products to HCOONa cement samples and the same dose-dependent trend. The main difference was a slightly more crystalline structure, as seen from the smaller shift of this decomposition peak to the right compared to sodium formate-doped samples. The ettringite content based on the decomposition peak height at around 160\u0026deg;C was higher than in the case of sodium formate-doped samples but lower than the reference. The promotion of ettringite formation by calcium formate is discussed in multiple articles [\u003cspan citationid=\"CR44\" class=\"CitationRef\"\u003e44\u003c/span\u003e] [\u003cspan citationid=\"CR45\" class=\"CitationRef\"\u003e45\u003c/span\u003e] [\u003cspan citationid=\"CR46\" class=\"CitationRef\"\u003e46\u003c/span\u003e] [\u003cspan citationid=\"CR47\" class=\"CitationRef\"\u003e47\u003c/span\u003e]. The height of the portlandite decomposition peaks seems to be comparable to the reference sample and slightly higher than the HCOONa-doped samples.\u003c/p\u003e \u003cp\u003eThe carbonate decomposition peaks of the sample with a maximum dose of Ca(HCOO)\u003csub\u003e2\u003c/sub\u003e are drastically larger than all other samples. This is due to increased carbonation of the sample caused by a large amount of added soluble calcium. The overall mass loss of the Ca(HCOO)\u003csub\u003e2\u003c/sub\u003e-doped samples is comparable to or somewhat larger than that of the reference sample. This points to larger similarities in the composition of these samples to the reference than the HCOONa-doped. It can thus be concluded that while Ca(HCOO)\u003csub\u003e2\u003c/sub\u003e is a more effective accelerator of the setting of a cement-zinc system than HCOONa, it does not change the hydration mechanism as much.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eIncreasing the content of zinc has a large impact on the hydration kinetics and mechanism. The TG-DTG measurements of cement paste containing 5 wt. % of zinc and doped with sodium and calcium formate are shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig10\" class=\"InternalRef\"\u003e10\u003c/span\u003e and Fig.\u0026nbsp;\u003cspan refid=\"Fig11\" class=\"InternalRef\"\u003e11\u003c/span\u003e. After 7 days of curing, the HCOONa-doped ZnO-cement samples had significantly different composition from the reference ZnO-OPC sample. The sample with minimal dose had a lower decomposition peak at around 80\u0026deg;C corresponding to C-S-H gel C [\u003cspan citationid=\"CR58\" class=\"CitationRef\"\u003e58\u003c/span\u003e] [\u003cspan citationid=\"CR59\" class=\"CitationRef\"\u003e59\u003c/span\u003e] and a lower peak at around 170\u0026deg;C corresponding to ettringite and unreacted gypsum [\u003cspan citationid=\"CR52\" class=\"CitationRef\"\u003e52\u003c/span\u003e] [\u003cspan citationid=\"CR53\" class=\"CitationRef\"\u003e53\u003c/span\u003e]. The decomposition peak of portlandite at around 420\u0026deg;C is slightly higher, indicating a slight acceleration of setting [\u003cspan citationid=\"CR60\" class=\"CitationRef\"\u003e60\u003c/span\u003e]. The overall mass loss is somewhat low, mainly due to lower silicate hydrate content.\u003c/p\u003e \u003cp\u003eThe maximum dose sample had a different composition from the reference and the previous sample. The TG-DTG curve had a wider C-S-H decomposition peak at around 100\u0026deg;C [\u003cspan citationid=\"CR58\" class=\"CitationRef\"\u003e58\u003c/span\u003e] [\u003cspan citationid=\"CR59\" class=\"CitationRef\"\u003e59\u003c/span\u003e], probably due to lower crystallinity and unreacted water, and a new peak at around 240\u0026deg;C [\u003cspan citationid=\"CR57\" class=\"CitationRef\"\u003e57\u003c/span\u003e]. This decomposition peak can be attributed to C\u003csub\u003e3\u003c/sub\u003eAH\u003csub\u003e6\u003c/sub\u003e aluminate hydrate that probably precipitated due to low ettringite content caused by destabilisation of ettringite through high alkali content in the pore solution and high ionic strength [\u003cspan citationid=\"CR61\" class=\"CitationRef\"\u003e61\u003c/span\u003e]. The higher decomposition peak of portlandite at around 420\u0026deg;C indicates a higher acceleration of setting than the lower dose. The higher decomposition peak between 600 and 800\u0026deg;C [\u003cspan citationid=\"CR54\" class=\"CitationRef\"\u003e54\u003c/span\u003e] [\u003cspan citationid=\"CR55\" class=\"CitationRef\"\u003e55\u003c/span\u003e] [\u003cspan citationid=\"CR56\" class=\"CitationRef\"\u003e56\u003c/span\u003e] is probably due to the increased content of carbonates in the sample, due to the presence of Na\u003csup\u003e+\u003c/sup\u003e ions.\u003c/p\u003e \u003cp\u003eThe calcium formate, compared to the HCOONa sample, shows acceleration of hydration. The decomposition peaks of C-S-H hydrates and ettringite are significantly higher than those of the sodium formate-doped and reference samples. The decomposition peak of portlandite at around 420\u0026deg;C is also visibly higher, proving the acceleration of setting [\u003cspan citationid=\"CR51\" class=\"CitationRef\"\u003e51\u003c/span\u003e]. The total mass loss increases with increasing dose of calcium formate. Thus, this compound effectively accelerates the setting event at 5 wt. % of zinc in the system.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eAfter 28 days of curing, as shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig11\" class=\"InternalRef\"\u003e11\u003c/span\u003e, the HCOONa-doped samples resemble the reference cement sample but have a lower ettringite and portlandite content. Similar development of composition is visible in samples doped with calcium formate. Neither of the doses drastically increased the content of ettringite and portlandite. The total mass loss of sodium and calcium formate-doped samples was lower than that of the reference. This could mean that at 5 wt. % of zinc, these compounds can only accelerate hydration in the early stages of curing.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003e \u003cem\u003eThe effects of formates \u0026ndash; XRD\u003c/em\u003e \u003c/p\u003e \u003cp\u003eXRD analyses provide structural information about the crystalline phases in the cement samples. This means that it does not represent the sample's total phase composition but the crystalline phase's relative composition. Coupled with TG-DTG analysis, it is possible to identify the mineral phases present in the samples and their changes. Phase composition of reference samples is shown in Table\u0026nbsp;\u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e3\u003c/span\u003e.\u003c/p\u003e \u003cp\u003eThe XRD results of the samples doped with sodium formate are presented in Table\u0026nbsp;\u003cspan refid=\"Tab4\" class=\"InternalRef\"\u003e4\u003c/span\u003e. The most important trends are the almost constant content of portlandite in samples without zinc and with 1 wt. % of zinc. The amount of portlandite does not significantly change with increasing dose or between curing times. This correlates with the TG-DTG results, where the portlandite decomposition peak had roughly the same height regardless of the dose and curing time. The explanation could be that sodium formate accelerates the early stages of hydration. Compared to the composition of the reference samples, the portlandite content is higher after 7 days of curing but lower after 28 days. This is most likely due to higher amorphous content, as acceleration was seen in the calorimetric results.\u003c/p\u003e \u003cp\u003eAnother important change is the ettringite content. In all samples with HCOONa, the amount of ettringite in early stages of hydration was either very low or below the detection limit. This could again be caused by higher amorphous content, but the decomposition peaks of ettringite were lower in the TG-DTG results. It can be concluded that HCOONa does not promote the formation of ettringite in the cement-ZnO system.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab3\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 3\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eRelative percentage composition of the reference samples\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"7\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c7\" colnum=\"7\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eDose and content of zinc\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e \u003cp\u003e0% Zn\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"2\" nameend=\"c5\" namest=\"c4\"\u003e \u003cp\u003e1% Zn\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"2\" nameend=\"c7\" namest=\"c6\"\u003e \u003cp\u003e5% Zn\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eDays of curing\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e7 d\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e28 d\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e7 d\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e28 d\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e7 d\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e28 d\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eC\u003csub\u003e3\u003c/sub\u003eS\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e27\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e19\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e57\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e27\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e63\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e33\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eC\u003csub\u003e2\u003c/sub\u003eS\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e18\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e19\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e16\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e19\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e14\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e19\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eC\u003csub\u003e4\u003c/sub\u003eAF\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e4\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePortlandite\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e36\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e40\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e34\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e24\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eEttringite\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e5\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCalcite\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e7\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eZnO\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCaZn\u003csub\u003e2\u003c/sub\u003e(OH)\u003csub\u003e6\u003c/sub\u003e∙2 H\u003csub\u003e2\u003c/sub\u003eO\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e6\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCa\u003csub\u003e4\u003c/sub\u003eAl\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e6\u003c/sub\u003e(CO\u003csub\u003e3\u003c/sub\u003e)(OH)\u003csub\u003e12\u003c/sub\u003e\u0026middot;5 H\u003csub\u003e2\u003c/sub\u003eO\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e2\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab4\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 4\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eThe relative phase composition of samples doped with HCOONa\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"13\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c7\" colnum=\"7\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c8\" colnum=\"8\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c9\" colnum=\"9\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c10\" colnum=\"10\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c11\" colnum=\"11\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c12\" colnum=\"12\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c13\" colnum=\"13\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eDose and content of zinc\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e \u003cp\u003eMin\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"2\" nameend=\"c5\" namest=\"c4\"\u003e \u003cp\u003eMax\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"2\" nameend=\"c7\" namest=\"c6\"\u003e \u003cp\u003eMin 1%\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"2\" nameend=\"c9\" namest=\"c8\"\u003e \u003cp\u003eMax 1%\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"2\" nameend=\"c11\" namest=\"c10\"\u003e \u003cp\u003eMin 5%\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"2\" nameend=\"c13\" namest=\"c12\"\u003e \u003cp\u003eMax 5%\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eDays of curing\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e7 d\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e28 d\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e7 d\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e28 d\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e7 d\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e28 d\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e7 d\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e28 d\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003e7 d\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c11\"\u003e \u003cp\u003e28 d\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c12\"\u003e \u003cp\u003e7 d\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c13\"\u003e \u003cp\u003e28 d\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eC\u003csub\u003e3\u003c/sub\u003eS\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e33\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e32\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e34\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e33\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e40\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e38\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e41\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e38\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003e62\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c11\"\u003e \u003cp\u003e55\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c12\"\u003e \u003cp\u003e62\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c13\"\u003e \u003cp\u003e58\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eC\u003csub\u003e2\u003c/sub\u003eS\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e18\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e19\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e17\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e20\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e20\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e21\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e19\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e22\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003e18\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c11\"\u003e \u003cp\u003e19\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c12\"\u003e \u003cp\u003e17\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c13\"\u003e \u003cp\u003e16\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eC\u003csub\u003e4\u003c/sub\u003eAF\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003e7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c11\"\u003e \u003cp\u003e6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c12\"\u003e \u003cp\u003e7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c13\"\u003e \u003cp\u003e6\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePortlandite\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e36\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e33\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e36\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e32\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e29\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e25\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e26\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e23\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c11\"\u003e \u003cp\u003e5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c12\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c13\"\u003e \u003cp\u003e6\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eEttringite\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c11\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c12\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c13\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCalcite\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003e4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c11\"\u003e \u003cp\u003e5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c12\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c13\"\u003e \u003cp\u003e5\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSiO\u003csub\u003e2\u003c/sub\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c11\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c12\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c13\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eZnO\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003e5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c11\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c12\"\u003e \u003cp\u003e5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c13\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCa(Zn\u003csub\u003e2\u003c/sub\u003e(OH)\u003csub\u003e6\u003c/sub\u003e)\u0026middot;2 H\u003csub\u003e2\u003c/sub\u003eO\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c11\"\u003e \u003cp\u003e4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c12\"\u003e \u003cp\u003e2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c13\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eMonosulphate\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c11\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c12\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c13\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCa\u003csub\u003e4\u003c/sub\u003eAl\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e6\u003c/sub\u003e(CO\u003csub\u003e3\u003c/sub\u003e)(OH)\u003csub\u003e12\u003c/sub\u003e\u0026middot;5 H\u003csub\u003e2\u003c/sub\u003eO\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c11\"\u003e \u003cp\u003e2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c12\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c13\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e3CaO\u0026middot;Al\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e3\u003c/sub\u003e\u0026middot;(HCOO)\u003csub\u003e2\u003c/sub\u003eCa\u0026middot;11 H\u003csub\u003e2\u003c/sub\u003eO\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c11\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c12\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c13\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003eThe XRD results of samples doped with calcium formate are presented in Table\u0026nbsp;\u003cspan refid=\"Tab5\" class=\"InternalRef\"\u003e5\u003c/span\u003e. At first glance, it is apparent that calcium formate had a higher content of portlandite than samples with sodium formate. This correlates with the TG-DTG results, where calcium formate-doped samples exhibited a larger Portlandite decomposition peak than sodium formate-doped samples, particularly after 28 days of curing. This confirms that calcium formate is a more effective accelerator of hydration than sodium formate.\u003c/p\u003e \u003cp\u003eThe content of ettringite was also higher, especially in the early stages of development. This means that calcium formate promotes the formation of ettringite, which seems to be crucial for accelerating the setting of zinc-contaminated cement. The increase in ettringite content in cement mortars containing calcium formate was described in multiple publications. Higher content of ettringite was found in both early and late stages of hydration. In these articles, a lower content of unhydrated C\u003csub\u003e3\u003c/sub\u003eA and gypsum was observed. Thus, the promotion of ettringite can be caused by increased availability of sulphate ions in the pore solution through consumption of available gypsum [\u003cspan citationid=\"CR44\" class=\"CitationRef\"\u003e44\u003c/span\u003e] [\u003cspan citationid=\"CR45\" class=\"CitationRef\"\u003e45\u003c/span\u003e] [\u003cspan citationid=\"CR46\" class=\"CitationRef\"\u003e46\u003c/span\u003e] [\u003cspan citationid=\"CR47\" class=\"CitationRef\"\u003e47\u003c/span\u003e].\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab5\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 5\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eThe relative phase composition of samples doped with (HCOO)\u003csub\u003e2\u003c/sub\u003eCa\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"13\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c7\" colnum=\"7\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c8\" colnum=\"8\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c9\" colnum=\"9\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c10\" colnum=\"10\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c11\" colnum=\"11\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c12\" colnum=\"12\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c13\" colnum=\"13\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eDose and content of zinc\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e \u003cp\u003eMin\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"2\" nameend=\"c5\" namest=\"c4\"\u003e \u003cp\u003eMax\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"2\" nameend=\"c7\" namest=\"c6\"\u003e \u003cp\u003eMin 1%\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"2\" nameend=\"c9\" namest=\"c8\"\u003e \u003cp\u003eMax 1%\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"2\" nameend=\"c11\" namest=\"c10\"\u003e \u003cp\u003eMin 5%\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"2\" nameend=\"c13\" namest=\"c12\"\u003e \u003cp\u003eMax 5%\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eDays of curing\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e7 d\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e28 d\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e7 d\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e28 d\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e7 d\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e28 d\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e7 d\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e28 d\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003e7 d\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c11\"\u003e \u003cp\u003e28 d\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c12\"\u003e \u003cp\u003e7 d\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c13\"\u003e \u003cp\u003e28 d\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eC\u003csub\u003e3\u003c/sub\u003eS\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e33\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e32\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e34\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e33\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e40\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e38\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e41\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e38\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003e62\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c11\"\u003e \u003cp\u003e55\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c12\"\u003e \u003cp\u003e62\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c13\"\u003e \u003cp\u003e58\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eC\u003csub\u003e2\u003c/sub\u003eS\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e18\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e19\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e17\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e20\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e20\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e21\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e19\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e22\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003e18\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c11\"\u003e \u003cp\u003e19\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c12\"\u003e \u003cp\u003e17\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c13\"\u003e \u003cp\u003e16\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eC\u003csub\u003e4\u003c/sub\u003eAF\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003e7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c11\"\u003e \u003cp\u003e6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c12\"\u003e \u003cp\u003e7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c13\"\u003e \u003cp\u003e6\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePortlandite\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e36\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e39\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e35\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e37\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e28\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e31\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e29\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e31\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003e4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c11\"\u003e \u003cp\u003e8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c12\"\u003e \u003cp\u003e2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c13\"\u003e \u003cp\u003e8\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eEttringite\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003e5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c11\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c12\"\u003e \u003cp\u003e5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c13\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCalcite\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003e4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c11\"\u003e \u003cp\u003e5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c12\"\u003e \u003cp\u003e5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c13\"\u003e \u003cp\u003e6\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSiO\u003csub\u003e2\u003c/sub\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c11\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c12\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c13\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eZnO\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c11\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c12\"\u003e \u003cp\u003e8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c13\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCa(Zn\u003csub\u003e2\u003c/sub\u003e(OH)\u003csub\u003e6\u003c/sub\u003e)\u0026middot;2 H\u003csub\u003e2\u003c/sub\u003eO\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c11\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c12\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c13\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eMonosulphate\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c11\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c12\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c13\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCa\u003csub\u003e4\u003c/sub\u003eAl\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e6\u003c/sub\u003e(CO\u003csub\u003e3\u003c/sub\u003e)(OH)\u003csub\u003e12\u003c/sub\u003e\u0026middot;5 H\u003csub\u003e2\u003c/sub\u003eO\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c11\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c12\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c13\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e3CaO\u0026middot;Al\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e3\u003c/sub\u003e\u0026middot;(HCOO)\u003csub\u003e2\u003c/sub\u003eCa\u0026middot;11 H\u003csub\u003e2\u003c/sub\u003eO\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c11\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c12\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c13\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e"},{"header":"5. Conclusion","content":"\u003cp\u003eThe The aim of this work was primarily to show a possible way to eliminate the negative effect of zinc on cement hydration using hydration accelerators. Formate salts are shown to be the most effective accelerators out of all tested compounds and products. These compounds drastically decreased setting time to the point of being comparable to pure reference OPC. There was also a slight improvement in the compressive strength of HCOONa and (HCOO)\u003csub\u003e2\u003c/sub\u003eCa doped samples, probably due to a decrease in porosity of the samples. The calcium formate was the most effective, drastically shortening setting time even in comparison to sodium and potassium formateUsing this accelerator, it is possible to reduce the time to reach the main hydration peak from 170 hours to less than 25 hours in the presence of 1% zinc. The probable cause of the different effectiveness of these compounds was the added soluble calcium, which promotes the formation of cement hydrates. The increased content of ettringite, in the presence of (HCOO)\u003csub\u003e2\u003c/sub\u003eCa, was indicative of effective acceleration of hydration of the ZnO-cement system. The possible mechanism behind the high effectiveness of formates could be the disruption of the Ca(Zn\u003csub\u003e2\u003c/sub\u003e(OH)\u003csub\u003e6\u003c/sub\u003e)\u0026middot;2 H\u003csub\u003e2\u003c/sub\u003eO layer on the surface of silicate cement phase grains due to the high diffusion rate of HCOO\u003csup\u003e\u0026minus;\u003c/sup\u003e through C-S-H gel.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e \u003ch2\u003eConflict of interest\u003c/h2\u003e \u003cp\u003eThe authors declare no conflict of interest.\u003c/p\u003e \u003c/p\u003e\u003ch2\u003eAuthor Contribution\u003c/h2\u003e\u003cp\u003ePS contributed to conceptualisation and editing, contributed to draft preparation, investigation, and formal analysis. LM contributed to draft preparation, investigation, and formal analysis. JS contributed to the investigation, data curation, formal analysis, and methodology. JM contributed to the investigation, data curation, formal analysis, and methodology. VF contributed to sample preparation and basic characterization, OK contributed to sample preparation and data evaluation, JK contributed to the investigation, data curation, formal analysis, and methodology. RN contributed to the investigation, data curation, formal analysis, and methodology. MS contributed to the investigation and data curation. FS contributed to administration and supervision.\u003c/p\u003e\u003ch2\u003eAcknowledgement\u003c/h2\u003e\u003cp\u003eThis outcome has been achieved with the financial support of the project GA19-16646S, \"The elimination of the negative impact of zinc in Portland cement by accelerating concrete admixtures\", with financial support from the Czech Science Foundation.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eYOUSUF, M.; MOLLAH, A.; VEMPATI, Rajan; LIN, T.-C. a COCKE, David. The interfacial chemistry of solidification/stabilization of metals in cement and pozzolanic material systems. \u003cem\u003eWaste Management\u003c/em\u003e. 1995, issue 15, č. 2, s. 137\u0026ndash;148. ISSN 0956053X. Available from: \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/0956-053X(95)00013-P\u003c/span\u003e\u003cspan address=\"10.1016/0956-053X(95)00013-P\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eANDRADE, F.R.D; MARINGOLO, V a KIHARA, Y. Incorporation of V, Zn and Pb into the crystalline phases of Portland clinker. online. \u003cem\u003eCement and Concrete Research\u003c/em\u003e. 2003, issue 33, č. 1, s. 63\u0026ndash;71. ISSN 00088846. Available from: \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/S0008-8846(02)00928-6\u003c/span\u003e\u003cspan address=\"10.1016/S0008-8846(02)00928-6\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e. [cit. 2024-05-19].\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eARLIGUIE, G.; OLLIVIER, J.P. a GRANDET, J. Etude de l'effet retardateur du zinc sur l'hydratation de la pate de ciment Portland. \u003cem\u003eCement and Concrete Research\u003c/em\u003e. 1982, issue 12, č. 1, s. 79\u0026ndash;86. ISSN 00088846. Available from: \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/0008-8846(82)90101-6\u003c/span\u003e\u003cspan address=\"10.1016/0008-8846(82)90101-6\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eGRANDET, J. a OLLIVIER, J.P. Study of the contact zone between zinc and Portland cement paste. \u003cem\u003eCement and Concrete Research\u003c/em\u003e. 1980, issue 10, č. 6, s. 759\u0026ndash;770. ISSN 00088846. Available from: \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/0008-8846(80)90004-6\u003c/span\u003e\u003cspan address=\"10.1016/0008-8846(80)90004-6\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eKEPPERT, Martin; JERMAN, Miloš; SCHEINHERROV\u0026Aacute;, Lenka; REITERMAN, Pavel; DOUŠOV\u0026Aacute;, Barbora et al. Influence of free and sorbed zinc on cement hydration. \u003cem\u003eJournal of Thermal Analysis and Calorimetry\u003c/em\u003e. 2019, issue 138, č. 3, s. 1935\u0026ndash;1943. ISSN 1388\u0026ndash;6150. Available from: \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1007/s10973-019-08200-0\u003c/span\u003e\u003cspan address=\"10.1007/s10973-019-08200-0\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eWEEKS, Caroline; HAND, Russell a SHARP, John. Retardation of cement hydration caused by heavy metals present in ISF slag used as aggregate. \u003cem\u003eCement and Concrete Composites\u003c/em\u003e. 2008, issue 30, č. 10, s. 970\u0026ndash;978. ISSN 09589465. Available from: \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/j.cemconcomp.2008.07.005\u003c/span\u003e\u003cspan address=\"10.1016/j.cemconcomp.2008.07.005\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eGINEYS, N.; AOUAD, G. a DAMIDOT, D. Managing trace elements in Portland cement \u0026ndash; Part I: Interactions between cement paste and heavy metals added during mixing as soluble salts. \u003cem\u003eCement and Concrete Composites\u003c/em\u003e. 2010, issue 32, č. 8, s. 563\u0026ndash;570. ISSN 09589465. Available from: \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/j.cemconcomp.2010.06.002\u003c/span\u003e\u003cspan address=\"10.1016/j.cemconcomp.2010.06.002\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eGINEYS, N.; AOUAD, G. a DAMIDOT, D. Managing trace elements in Portland cement \u0026ndash; Part II: Comparison of two methods to incorporate Zn in a cement. \u003cem\u003eCement and Concrete Composites\u003c/em\u003e. 2011, issue 33, č. 6, s. 629\u0026ndash;636. ISSN 09589465. Available from: \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/j.cemconcomp.2011.03.008\u003c/span\u003e\u003cspan address=\"10.1016/j.cemconcomp.2011.03.008\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eYOUSUF, M.; MOLLAH, A.; HESS, Thomas; TSAI, Yung-Nien a COCKE, David. An FTIR and XPS investigations of the effects of carbonation on the solidification/stabilization of cement based systems-Portland type V with zinc. \u003cem\u003eCement and Concrete Research\u003c/em\u003e. 1993, issue 23, č. 4, s. 773\u0026ndash;784. ISSN 00088846. Available from: \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/0008-8846(93)90031-4\u003c/span\u003e\u003cspan address=\"10.1016/0008-8846(93)90031-4\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eARLIGUIE, G. a GRANDET, J. Influence de la composition d'un ciment portland sur son hydration en presence de zinc. \u003cem\u003eCement and Concrete Research\u003c/em\u003e. 1990, issue 20, č. 4, s. 517\u0026ndash;524. ISSN 00088846. Available from: \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/0008-8846(90)90096-G\u003c/span\u003e\u003cspan address=\"10.1016/0008-8846(90)90096-G\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eATAIE, Feraidon; JUENGER, Maria; TAYLOR-LANGE, Sarah a RIDING, Kyle. Comparison of the retarding mechanisms of zinc oxide and sucrose on cement hydration and interactions with supplementary cementitious materials. \u003cem\u003eCement and Concrete Research\u003c/em\u003e. 2015, issue 72, s. 128\u0026ndash;136. ISSN 00088846. Available from: \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/j.cemconres.2015.02.023\u003c/span\u003e\u003cspan address=\"10.1016/j.cemconres.2015.02.023\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eGINEYS, N.; AOUAD, G.; SORRENTINO, F. a DAMIDOT, D. Incorporation of trace elements in Portland cement clinker: Thresholds limits for Cu, Ni, Sn or Zn. \u003cem\u003eCement and Concrete Research\u003c/em\u003e. 2011, issue 41, č. 11, s. 1177\u0026ndash;1184. ISSN 00088846. Available from: \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/j.cemconres.2011.07.006\u003c/span\u003e\u003cspan address=\"10.1016/j.cemconres.2011.07.006\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLAGO, Fernanda; GON\u0026ccedil;ALVES, Jardel; DWECK, Jo a CUNHA, Armando. Evaluation of Influence of Salt in the Cement Hydration to Oil Wells. \u003cem\u003eMaterials Research\u003c/em\u003e. 2017, issue 20, č. 2, s. 743\u0026ndash;747. ISSN 1980\u0026ndash;5373. Available from: \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1590/1980-5373-mr-2017-0049\u003c/span\u003e\u003cspan address=\"10.1590/1980-5373-mr-2017-0049\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eCHEN, Q.Y.; TYRER, M.; HILLS, C.D.; YANG, X.M. a CAREY, P. Immobilisation of heavy metal in cement-based solidification/stabilisation: A review. \u003cem\u003eWaste Management\u003c/em\u003e. 2009, issue 29, č. 1, s. 390\u0026ndash;403. ISSN 0956053X. Available from: \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/j.wasman.2008.01.019\u003c/span\u003e\u003cspan address=\"10.1016/j.wasman.2008.01.019\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eOUKI, S.K a HILLS, C.D. Microstructure of Portland cement pastes containing metal nitrate salts. \u003cem\u003eWaste Management\u003c/em\u003e. 2002, issue 22, č. 2, s. 147\u0026ndash;151. ISSN 0956053X. Available from: \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/S0956-053X(01)00063-0\u003c/span\u003e\u003cspan address=\"10.1016/S0956-053X(01)00063-0\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLI, Xiang; YIN, Xiao; MA, Bao; WU, Bei; CHEN, Quanbin et al. Investigation on Hydration Characteristics of Zinc-Doped Portland Cement Pastes. \u003cem\u003eAdvanced Materials Research\u003c/em\u003e. 2010, issue 168\u0026ndash;170, s. 623\u0026ndash;627. ISSN 1662\u0026ndash;8985. Available from: \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.4028/www.scientific.net/AMR.168-170.623\u003c/span\u003e\u003cspan address=\"10.4028/www.scientific.net/AMR.168-170.623\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLIU, Jintao; JIN, Hang; GU, Chunping a YANG, Yang. Effects of zinc oxide nanoparticles on early-age hydration and the mechanical properties of cement paste. \u003cem\u003eConstruction and Building Materials\u003c/em\u003e. 2019, issue 217, s. 352\u0026ndash;362. ISSN 09500618. Available from: \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/j.conbuildmat.2019.05.027\u003c/span\u003e\u003cspan address=\"10.1016/j.conbuildmat.2019.05.027\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eNOCHAIYA, Thanongsak; SEKINE, Yoshika; CHOOPUN, Supab a CHAIPANICH, Arnon. Microstructure, characterizations, functionality and compressive strength of cement-based materials using zinc oxide nanoparticles as an additive. \u003cem\u003eJournal of Alloys and Compounds\u003c/em\u003e. 2015, issue 630, s. 1\u0026ndash;10. ISSN 09258388. Available from: \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/j.jallcom.2014.11.043\u003c/span\u003e\u003cspan address=\"10.1016/j.jallcom.2014.11.043\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eŠILER, Pavel; KOL\u0026Aacute;ŘOV\u0026Aacute;, Iva; NOVOTN\u0026Yacute;, Radoslav; M\u0026Aacute;SILKO, Jiř\u0026iacute;; POŘ\u0026Iacute;ZKA, Jarom\u0026iacute;r et al. Application of isothermal and isoperibolic calorimetry to assess the effect of zinc on cement hydration. online. \u003cem\u003eJournal of Thermal Analysis and Calorimetry\u003c/em\u003e. 2018, issue 133, č. 1, s. 27\u0026ndash;40. ISSN 1388\u0026ndash;6150. Available from: \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1007/s10973-017-6815-1\u003c/span\u003e\u003cspan address=\"10.1007/s10973-017-6815-1\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e. [cit. 2024-05-08].\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eŠILER,; KOL\u0026Aacute;ŘOV\u0026Aacute;, ; NOVOTN\u0026Yacute;, ; M\u0026Aacute;SILKO, ; BEDN\u0026Aacute;REK, et al. Application of Isothermal and Isoperibolic Calorimetry to Assess the Effect of Zinc on Hydration of Cement Blended with Slag. online. \u003cem\u003eMaterials\u003c/em\u003e. 2019, issue 12, č. 18. ISSN 1996\u0026thinsp;\u0026ndash;\u0026thinsp;1944. Available from: \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.3390/ma12182930\u003c/span\u003e\u003cspan address=\"10.3390/ma12182930\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e. [cit. 2024-05-11].\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eŠILER, Pavel; KOL\u0026Aacute;ŘOV\u0026Aacute;, Iva; NOVOTN\u0026Yacute;, Radoslav; M\u0026Aacute;SILKO, Jiř\u0026iacute;; BEDN\u0026Aacute;REK, Jan et al. Use of Isothermal and Isoperibolic Calorimetry to Study the Effect of Zinc on Hydration of Cement Blended with Fly Ash. online. \u003cem\u003eMaterials\u003c/em\u003e. 2020, issue 13, č. 22. ISSN 1996\u0026thinsp;\u0026ndash;\u0026thinsp;1944. Available from: \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.3390/ma13225215\u003c/span\u003e\u003cspan address=\"10.3390/ma13225215\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e. [cit. 2024-05-11].\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003e\u003cem\u003eAdvanced cementing materials: Controlling hydration development Accelerating admixtures for concrete\u003c/em\u003e. 2007. Available from: \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://www.sintef.no/globalassets/sintef-byggforsk/coin/sintef-reports/sbf-bk-a07025_accelerating-admixtures-for-concrete.pdf\u003c/span\u003e\u003cspan address=\"https://www.sintef.no/globalassets/sintef-byggforsk/coin/sintef-reports/sbf-bk-a07025_accelerating-admixtures-for-concrete.pdf\" targettype=\"URL\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003e\u003cem\u003eReport on Chemical Admixtures for Concrete\u003c/em\u003e. American Concrete Institute, 2010. Available from: \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://www.concrete.org/store/productdetail.aspx?ItemID=212310\u003c/span\u003e\u003cspan address=\"https://www.concrete.org/store/productdetail.aspx?ItemID=212310\" targettype=\"URL\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u0026amp;Format=DOWNLOAD\u0026amp;Language=English\u0026amp;Units=US_Units.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eA\u0026iuml;TCIN, Pierre-Claude a FLATT, Robert. \u003cem\u003eScience and technology of concrete admixtures\u003c/em\u003e. Woodhead Publishing series in civil and structural engineering, no. 59. Amsterdam: Elsevir, 2016. ISBN 978-0-08-100693-1.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eRIXOM, M. a MAILVAGANAM, N.P. \u003cem\u003eChemical admixtures for concrete\u003c/em\u003e. 3rd ed. New York: Routledge, 1999. ISBN 04-192-2520-X.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eMATEJKA, Lukas; SILER, Pavel; NOVOTNY, Radoslav; SVEC, Jiri; MASILKO, Jiri et al. The thermal analysis of zinc oxide-contaminated Portland cement blended with thiocyanates and determination of their effect on hydration and properties. online. \u003cem\u003eJournal of Thermal Analysis and Calorimetry\u003c/em\u003e. 2023, issue 148, č. 4, s. 1321\u0026ndash;1349. ISSN 1388\u0026ndash;6150. Available from: \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1007/s10973-022-11666-0\u003c/span\u003e\u003cspan address=\"10.1007/s10973-022-11666-0\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e. [cit. 2025-07-06].\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eMATEJKA, Lukas; SILER, Pavel; SVEC, Jiri; MASILKO, Jiri; KOPLIK, Jan et al. Comparison of commercial nitrate-based accelerators and their pure constituents on hydration kinetics, composition, and hydration degree of zinc oxide blended Portland cement. online. \u003cem\u003eJournal of Thermal Analysis and Calorimetry\u003c/em\u003e. ISSN 1388\u0026ndash;6150. Available from: \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1007/s10973-025-14193-w\u003c/span\u003e\u003cspan address=\"10.1007/s10973-025-14193-w\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e. [cit. 2025-07-06].\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSINGH, N.B. a ABHA, Km. Effect of calcium formate on the hydration of tricalcium silicate. \u003cem\u003eCement and Concrete Research\u003c/em\u003e. 1983, issue 13, č. 5, s. 619\u0026ndash;625. ISSN 00088846. Available from: \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/0008-8846(83)90050-9\u003c/span\u003e\u003cspan address=\"10.1016/0008-8846(83)90050-9\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eDORN, Tobias; BLASK, Oliver a STEPHAN, Dietmar. Acceleration of cement hydration \u0026ndash; A review of the working mechanisms, effects on setting time, and compressive strength development of accelerating admixtures. online. \u003cem\u003eConstruction and Building Materials\u003c/em\u003e. 2022, issue 323. ISSN 09500618. Available from: \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/j.conbuildmat.2022.126554\u003c/span\u003e\u003cspan address=\"10.1016/j.conbuildmat.2022.126554\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e. [cit. 2025-06-17].\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eHEMALATHA, T. a SASMAL, Saptarshi. Early-age strength development in fly ash blended cement composites: investigation through chemical activation. online. \u003cem\u003eMagazine of Concrete Research\u003c/em\u003e. 2019, issue 71, č. 5, s. 260\u0026ndash;270. ISSN 0024-9831. Available from: \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1680/jmacr.17.00336\u003c/span\u003e\u003cspan address=\"10.1680/jmacr.17.00336\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e. [cit. 2025-06-17].\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eHEIKAL, Mohamed. Effect of calcium formate as an accelerator on the physicochemical and mechanical properties of pozzolanic cement pastes. \u003cem\u003eCement and Concrete Research\u003c/em\u003e. 2004, issue 34, č. 6, s. 1051\u0026ndash;1056. ISSN 00088846. Available from: \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/j.cemconres.2003.11.015\u003c/span\u003e\u003cspan address=\"10.1016/j.cemconres.2003.11.015\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eWANG, Yifei; LEI, Lei; LIU, Jianhui; MA, Yihan; LIU, Yi et al. Accelerators for normal concrete: A critical review on hydration, microstructure and properties of cement-based materials. online. \u003cem\u003eCement and Concrete Composites\u003c/em\u003e. 2022, issue 134. ISSN 09589465. Available from: \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/j.cemconcomp.2022.104762\u003c/span\u003e\u003cspan address=\"10.1016/j.cemconcomp.2022.104762\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e. [cit. 2025-03-27].\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLEVITT, Maurice. \u003cem\u003ePrecast Concrete: Materials, manufacture, properties and usage\u003c/em\u003e. online. 1st. CRC Press, 1982. ISBN 9780429208461. Available from: \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.4324/9780203490570\u003c/span\u003e\u003cspan address=\"10.4324/9780203490570\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e. [cit. 2025-06-17].\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSUH, Jung-Il; YUM, Woo; JEONG, Yeonung; PARK, Hong-Gun a EUN OH, Jae. The cation-dependent effects of formate salt additives on the strength and microstructure of CaO-activated fly ash binders. online. \u003cem\u003eConstruction and Building Materials\u003c/em\u003e. 2019, issue 194, s. 92\u0026ndash;101. ISSN 09500618. Available from: \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/j.conbuildmat.2018.11.008\u003c/span\u003e\u003cspan address=\"10.1016/j.conbuildmat.2018.11.008\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e. [cit. 2025-03-27].\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSNELLINGS, Ruben; CHWAST, Jacek; CIZER, \u0026Ouml;zlem; DE BELIE, Nele; DHANDAPANI, Yuvaraj et al. RILEM TC-238 SCM recommendation on hydration stoppage by solvent exchange for the study of hydrate assemblages. \u003cem\u003eMaterials and Structures\u003c/em\u003e. 2018, issue 51, č. 6. ISSN 1359\u0026ndash;5997. Available from: \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1617/s11527-018-1298-5\u003c/span\u003e\u003cspan address=\"10.1617/s11527-018-1298-5\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eBRANDŠTETR, J; POLCER, J; KR\u0026Aacute;TK\u0026Yacute;, J; HOLEŠINSK\u0026Yacute;, R a HAVLICA, J. Possibilities of the use of isoperibolic calorimetry for assessing the hydration behavior of cementitious systems. \u003cem\u003eCement and Concrete Research\u003c/em\u003e. 2001, issue 31, č. 6, s. 941\u0026ndash;947. ISSN 00088846. Available from: \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/S0008-8846(01)00495-1\u003c/span\u003e\u003cspan address=\"10.1016/S0008-8846(01)00495-1\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eŠILER, Pavel; KOL\u0026Aacute;ŘOV\u0026Aacute;, Iva; NOVOTN\u0026Yacute;, Radoslav; M\u0026Aacute;SILKO, Jiř\u0026iacute;; POŘ\u0026Iacute;ZKA, Jarom\u0026iacute;r et al. Application of isothermal and isoperibolic calorimetry to assess the effect of zinc on cement hydration. Journal of Thermal Analysis and Calorimetry. 2018, issue 133, č. 1, s. 27\u0026ndash;40. ISSN 1388\u0026ndash;6150. Available from: \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1007/s10973-017-6815-1\u003c/span\u003e\u003cspan address=\"10.1007/s10973-017-6815-1\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSILER, P.; KRATKY, J. a DE BELIE, N. Isothermal and solution calorimetry to assess the effect of superplasticizers and mineral admixtures on cement hydration. online. \u003cem\u003eJournal of Thermal Analysis and Calorimetry\u003c/em\u003e. 2012, issue 107, č. 1, s. 313\u0026ndash;320. ISSN 1388\u0026ndash;6150. Available from: \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1007/s10973-011-1479-8\u003c/span\u003e\u003cspan address=\"10.1007/s10973-011-1479-8\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e. [cit. 2024-05-08].\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eŠILER, Pavel; BAYER, Petr; SEHNAL, Tom\u0026aacute;š; KOL\u0026Aacute;ŘOV\u0026Aacute;, Iva; OPRAVIL, Tom\u0026aacute;š et al. Effects of high-temperature fly ash and fluidized bed combustion ash on the hydration of Portland cement. online. \u003cem\u003eConstruction and Building Materials\u003c/em\u003e. 2015, issue 78, s. 181\u0026ndash;188. ISSN 09500618. Available from: \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/j.conbuildmat.2015.01.032\u003c/span\u003e\u003cspan address=\"10.1016/j.conbuildmat.2015.01.032\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e. [cit. 2024-05-11].\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eŠILER, Pavel; KOL\u0026Aacute;ŘOV\u0026Aacute;, Iva; KR\u0026Aacute;TK\u0026Yacute;, Josef; HAVLICA, Jarom\u0026iacute;r a BRANDŠTETR, Jiř\u0026iacute;. Influence of superplasticizers on the course of Portland cement hydration. online. \u003cem\u003eChemical Papers\u003c/em\u003e. 2014, issue 68, č. 1. ISSN 1336\u0026ndash;9075. Available from: \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.2478/s11696-013-0413-x\u003c/span\u003e\u003cspan address=\"10.2478/s11696-013-0413-x\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e. [cit. 2025-12-05].\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eCharacterization, testing, and reinforcing materials of biodegradable composites. In: \u003cem\u003eBiodegradable and biocompatible polymer composites: processing, properties and applications\u003c/em\u003e. Woodhead Publishing series in composites science and engineering. Duxford: Woodhead Publishing, Elsevier, 2018, s. 55\u0026ndash;79. ISBN 978-0-08-100970-3.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eKOHLI, Rajiv a MITTAL, K. (ed.). \u003cem\u003eDevelopments in surface contamination and cleaning: fundamentals and applied aspects\u003c/em\u003e. 12. Oxford, UK: Elsevier, 2019. ISBN 978-0-8155-1555-5.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003e\u0026Ccedil;OPUR, Mehmet. Optimization of dissolution of Zn and Cd metals from Waelz sintering waste by in aqueous (NH4)2SO4 solution. online. \u003cem\u003eEnergy Education Science and Technology Part A: Energy Science and Research\u003c/em\u003e. 2010, issue 25, s. 17\u0026ndash;29. Available from: \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://www.researchgate.net/publication/287849567_Optimization_of_dissolution_of_Zn_and_Cd_metals_from_Waelz_sintering_waste_by_in_aqueous_NH_4_2SO_4_solution\u003c/span\u003e\u003cspan address=\"https://www.researchgate.net/publication/287849567_Optimization_of_dissolution_of_Zn_and_Cd_metals_from_Waelz_sintering_waste_by_in_aqueous_NH_4_2SO_4_solution\" targettype=\"URL\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e. [cit. 2025-05-16].\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eDERAKHSHANI, Aliakbar; GHADI, Arezoo a VAHDAT, Seyed. Study of the effect of calcium nitrate, calcium formate, triethanolamine, and triisopropanolamine on compressive strength of Portland-pozzolana cement. online. \u003cem\u003eCase Studies in Construction Materials\u003c/em\u003e. 2023, issue 18, s. 01799. ISSN 2214\u0026ndash;5095. Available from: \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/j.cscm.2022.e01799\u003c/span\u003e\u003cspan address=\"10.1016/j.cscm.2022.e01799\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e. [cit. 2025-08-23].\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eWANG, Yimu; JIA, Jinqing; CAO, Qi a GAO, Xing. Effect of calcium formate on the compressive strength, and hydration process of cement composite containing fly ash and slag. online. \u003cem\u003eJournal of Building Engineering\u003c/em\u003e. 2022, issue 50, s. 104133. ISSN 2352\u0026ndash;7102. Available from: \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/j.jobe.2022.104133\u003c/span\u003e\u003cspan address=\"10.1016/j.jobe.2022.104133\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e. [cit. 2025-08-23].\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eP\u0026icirc;RVAN, Adrian-Alexandru; LOTHENBACH, Barbara; SCHR\u0026Ouml;DER, Miriam; SCHWENDINGER, Michael; YAMMINE-MALESYS, Joumana et al. Enhancing slag reaction in cement blends using calcium formate and sodium metasilicate activators. online. \u003cem\u003eCement and Concrete Composites\u003c/em\u003e. 2025, issue 164, s. 106215. ISSN 0958\u0026ndash;9465. Available from: \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/j.cemconcomp.2025.106215\u003c/span\u003e\u003cspan address=\"10.1016/j.cemconcomp.2025.106215\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e. [cit. 2025-08-23].\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eXU, Wenbin; LI, Qianlong a HARUNA, Sada. The Effect of Calcium Formate, Sodium Sulfate, and Cement Clinker on Engineering Properties of Fly Ash-Based Cemented Tailings Backfill. online. \u003cem\u003eAdvances in Materials Science and Engineering\u003c/em\u003e. 2019, issue 2019, s. 1\u0026ndash;12. ISSN 1687\u0026ndash;8434. Available from: \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1155/2019/5370360\u003c/span\u003e\u003cspan address=\"10.1155/2019/5370360\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e. [cit. 2025-08-23].\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eREN, Guosheng; TIAN, Zhijie; WU, Jingjiang a GAO, Xiaojian. Effects of combined accelerating admixtures on mechanical strength and microstructure of cement mortar. online. \u003cem\u003eConstruction and Building Materials\u003c/em\u003e. 2021, issue 304, s. 124642. ISSN 0950\u0026thinsp;\u0026ndash;\u0026thinsp;0618. Available from: \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/j.conbuildmat.2021.124642\u003c/span\u003e\u003cspan address=\"10.1016/j.conbuildmat.2021.124642\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e. [cit. 2025-08-23].\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eGENG, Chaohui. THE EFFECT OF CALCIUM FORMATE ON THE PERFORMANCE OF SUPERSULFATED CEMENT. online. \u003cem\u003eCeramics - Silikaty\u003c/em\u003e. 2024, s. 216\u0026ndash;224. ISSN 1804\u0026ndash;5847. Available from: \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.13168/cs.2024.0021\u003c/span\u003e\u003cspan address=\"10.13168/cs.2024.0021\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e. [cit. 2025-08-23].\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eŠVEC, Jiř\u0026iacute;; ŠILER, Pavel; M\u0026Aacute;SILKO, Jiř\u0026iacute;; NOVOTN\u0026Yacute;, Radoslav; KOPL\u0026Iacute;K, Jan et al. Simultaneous thermogravimetric and differential thermal analysis determination of products formed during hydration of blended Portland cement doped with zinc. \u003cem\u003eJournal of Thermal Analysis and Calorimetry\u003c/em\u003e. 2020, issue 142, č. 5, s. 1749\u0026ndash;1758. ISSN 1388\u0026ndash;6150. Available from: \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1007/s10973-020-10253-5\u003c/span\u003e\u003cspan address=\"10.1007/s10973-020-10253-5\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eMURZYN, Paweł; MALATA, Grzegorz; WIśNIEWSKA, Joanna; KAPELUSZNA, Ewa a NOCUń-WCZELIK, Wiesława. Characterization of 40-year-old calcium silicate pastes by thermal methods and other techniques. \u003cem\u003eJournal of Thermal Analysis and Calorimetry\u003c/em\u003e. 2019, issue 138, č. 6, s. 4271\u0026ndash;4278. ISSN 1388\u0026ndash;6150. Available from: \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1007/s10973-019-08519-8\u003c/span\u003e\u003cspan address=\"10.1007/s10973-019-08519-8\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eALARCON-RUIZ, Lucia; PLATRET, Gerard; MASSIEU, Etienne a EHRLACHER, Alain. The use of thermal analysis in assessing the effect of temperature on a cement paste. \u003cem\u003eCement and Concrete Research\u003c/em\u003e. 2005, issue 35, č. 3, s. 609\u0026ndash;613. ISSN 00088846. Available from: \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/j.cemconres.2004.06.015\u003c/span\u003e\u003cspan address=\"10.1016/j.cemconres.2004.06.015\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eZHOU, Q. a GLASSER, F.P. Thermal stability and decomposition mechanisms of ettringite at \u0026lt;\u0026thinsp;120\u0026deg;C. \u003cem\u003eCement and Concrete Research\u003c/em\u003e. 2001, issue 31, č. 9, s. 1333\u0026ndash;1339. ISSN 00088846. Available from: \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/S0008-8846(01)00558-0\u003c/span\u003e\u003cspan address=\"10.1016/S0008-8846(01)00558-0\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eJO, Dweck; LEONARDO, Rosangela; CARTLEDGE, Frank; REALES, Oscar a TOLEDO FILHO, Romildo. Gypsum content determination in Portland cements by thermogravimetry. \u003cem\u003eJournal of Thermal Analysis and Calorimetry\u003c/em\u003e. 2016, issue 123, č. 2, s. 1053\u0026ndash;1062. ISSN 1388\u0026ndash;6150. Available from: \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1007/s10973-015-5078-y\u003c/span\u003e\u003cspan address=\"10.1007/s10973-015-5078-y\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eZAJAC, Maciej; ROSSBERG, Anne; LE SAOUT, Gwenn a LOTHENBACH, Barbara. Influence of limestone and anhydrite on the hydration of Portland cements. \u003cem\u003eCement and Concrete Composites\u003c/em\u003e. 2014, issue 46, s. 99\u0026ndash;108. ISSN 09589465. Available from: \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/j.cemconcomp.2013.11.007\u003c/span\u003e\u003cspan address=\"10.1016/j.cemconcomp.2013.11.007\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eCHAUNSALI, Piyush a MONDAL, Paramita. Influence of Mineral Admixtures on Early-Age Behavior of Calcium Sulfoaluminate Cement. \u003cem\u003eACI Materials Journal\u003c/em\u003e. 2015, issue 112, č. 1. ISSN 0889-325X. Available from: \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.14359/51687240\u003c/span\u003e\u003cspan address=\"10.14359/51687240\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eCOLLIER, Nick C. TRANSITION AND DECOMPOSITION TEMPERATURES OF CEMENT PHASES - A COLLECTION OF THERMAL ANALYSIS DATA. online. \u003cem\u003eCeramics - Silikaty\u003c/em\u003e. 2016, issue 60, č. 4, s. 338\u0026ndash;343. ISSN 1804\u0026ndash;5847. Available from: \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.13168/cs.2016.0050\u003c/span\u003e\u003cspan address=\"10.13168/cs.2016.0050\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e. [cit. 2025-12-18].\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSNELLINGS, Ruben; CHWAST, Jacek; CIZER, \u0026Ouml;zlem; DE BELIE, Nele; DHANDAPANI, Yuvaraj et al. Report of TC 238-SCM: hydration stoppage methods for phase assemblage studies of blended cements\u0026mdash;results of a round robin test. \u003cem\u003eMaterials and Structures\u003c/em\u003e. 2018, issue 51, č. 4. ISSN 1359\u0026ndash;5997. Available from: \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1617/s11527-018-1237-5\u003c/span\u003e\u003cspan address=\"10.1617/s11527-018-1237-5\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eMITCHELL, L. a MARGESON, J. The effects of solvents on C\u0026ndash;S\u0026ndash;H as determined by thermal analysis. \u003cem\u003eJournal of Thermal Analysis and Calorimetry\u003c/em\u003e. 2006, issue 86, č. 3, s. 591\u0026ndash;594. ISSN 1388\u0026ndash;6150. Available from: \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1007/s10973-006-7712-1\u003c/span\u003e\u003cspan address=\"10.1007/s10973-006-7712-1\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eHAWLETT, Peter C. \u003cem\u003eLea's Chemistry of Cement and Concrete\u003c/em\u003e. 4th. Elsevier Science \u0026amp; Technology Books, 2004. ISBN 978-0-7506-6256-7.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003ePHROMPET, Chaiwat; SRIWONG, Chaval a RUTTANAPUN, Chesta. Mechanical, dielectric, thermal and antibacterial properties of reduced graphene oxide (rGO)-nanosized C3AH6 cement nanocomposites for smart cement-based materials. online. \u003cem\u003eComposites Part B: Engineering\u003c/em\u003e. 2019, issue 175. ISSN 13598368. Available from: \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/j.compositesb.2019.107128\u003c/span\u003e\u003cspan address=\"10.1016/j.compositesb.2019.107128\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e. [cit. 2025-06-26].\u003c/span\u003e\u003c/li\u003e \u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"Thermal analysis, Portland cement, Zinc oxide, Hydration retardation, Setting accelerators","lastPublishedDoi":"10.21203/rs.3.rs-8459865/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-8459865/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eCement is the most important binder in the construction industry, produced globally in substantial quantities. Due to the utilization of used tires as fuel in clinker burning and the incorporation of secondary raw materials with a higher zinc content, the quantity of zinc in cement is steadily increasing. Zinc in cement exhibits adverse properties, primarily due to a significant retardation of hydration. Formic acid and its salts appear to be effective accelerators for enhancing the hydration of cements with elevated zinc levels. Within the scope of this study, the influence of pure formic acid as well as sodium, potassium, and calcium formates was investigated. Zinc was introduced in the form of ZnO. The effect of zinc on hydration was monitored using isoperibolic calorimetry. The formation of new products was tracked via differential thermal analysis (DTA) and X-ray diffraction analysis (XRD). The compressive strength of the samples was also measured. The results indicate that the application of formic acid and its salts in zinc-doped cements leads to a substantial reduction in the time required for hydration and concurrently results in an increase in compressive strength, both in cements without zinc and in those doped with zinc.\u003c/p\u003e","manuscriptTitle":"Influence of formic acid and its salts on the elimination of the negative effect of zinc in portland cement","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2026-02-24 14:19:44","doi":"10.21203/rs.3.rs-8459865/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"97a33c3d-cf2a-4030-8a5b-4b73ed141b2a","owner":[],"postedDate":"February 24th, 2026","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2026-04-27T21:39:01+00:00","versionOfRecord":[],"versionCreatedAt":"2026-02-24 14:19:44","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-8459865","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-8459865","identity":"rs-8459865","version":["v1"]},"buildId":"XKTyCvWXoU3ODBz1xrDgd","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}