Optimizations on Multi-Mineral Clayey Soil to Develop Limestone Calcined Clay Cement (LC3) Based Composite

Optimizations on Multi-Mineral Clayey Soil to Develop Limestone Calcined Clay Cement (LC3) Based Composite | 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 Article Optimizations on Multi-Mineral Clayey Soil to Develop Limestone Calcined Clay Cement (LC3) Based Composite Arass Omer Mawlod, Aram Aziz This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-6804995/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 14 Apr, 2026 Read the published version in Scientific Reports → Version 1 posted 11 You are reading this latest preprint version Abstract The cement industry plays a significant role in contributing to global carbon dioxide emissions, representing a considerable portion of the total environmental impact. In response to growing environmental concerns, supplementary cementitious materials such as calcined clay and limestone have gained prominence due to their abundance and reduced carbon footprint. Among these, Limestone Calcined Clay Cement (LC3) has emerged as a promising sustainable alternative to ordinary Portland cement (OPC). This study investigates the feasibility of utilizing locally available non-kaolinitic clayey soil in the development of LC3-based binders. The research was conducted in two phases: initially, the optimum calcination temperature, substitution level of calcined clay, and calcined clay-to-limestone ratio (CC:LS) were determined, yielding optimal values of 650°C, 30%, and 2:1, respectively. Subsequently, the optimal binder compositions were reinforced with recycled sheep wool (Wl) and polypropylene (PP) fibers at varying dosages of 0%, 0.5%, 1%, and 1.5% by binder weight. Fresh mortar flowability was assessed, followed by evaluation of mechanical properties including compressive strength, flexural strength, and splitting tensile strength. Durability parameters such as fire resistance, water absorption, water sorptivity, and porosity were also examined. The results indicated that fiber additions of 1.5% Wl and 1% PP offered the best balance of mechanical performance and durability. However, increasing fiber content consistently reduced flowability. Overall, the findings demonstrate the viability of using locally sourced clayey soil as a pozzolanic material in LC3 production and highlight LC3 potential as a sustainable structural material. Physical sciences/Engineering/Civil engineering Biological sciences/Ecology Physical sciences/Materials science LC3 calcined clay flowability splitting tensile strength fire resistance Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 Figure 9 Figure 10 Figure 11 Figure 12 Figure 13 Figure 14 Figure 15 Figure 16 Figure 17 Figure 18 Figure 19 Figure 20 Figure 21 Figure 22 1. Introduction The cement industry is progressively adopting natural pozzolans as supplementary cementitious materials (SCMs) in an effort to adress its environmental impacts. Cement production is highly energy-intensive and is responsible for approximately 7–8% of global CO₂ emissions (Andrew, 2018 ). Incorporating SCMs into cement formulations has proven to be an effective approach to mitigate emissions by up to 40% without sacrificing concrete quality (Skibsted and Snellings, 2019 ). In pursuit of more sustainable construction practices, researchers are designing advanced cement blends. One such approach is Limestone Calcined Clay Cement (LC3), which utilizes high proportions of calcined clay and limestone. This blend (LC3) is especially particularly beneficial in regions with limited industrial waste materials like fly ash or slag. Substituting 50% of Ordinary Portland Cement (OPC) with a combination of calcined clay and limestone (LC3-50) has been shown to reduce CO₂ emissions by around 30% (Gettu et al., 2019 ; Murray, 2000 ). The scarcity of industrial by-products has driven research toward the utilization of locally available clays as alternative SCMs. For instance, Blouch et al. (2023) reported that LC3 produced with low-kaolinite clays can achieve up to 96% of the compressive strength of OPC-based concrete. In addition to kaolinite, other clays such as montmorillonite, illite, and mixed clays have shown pozzolanic potential, particularly when calcined at temperatures ranging from 600–850°C, these clays yield strength activity indices between 0.70 to 0.76 (Garg and Skibsted, 2014 ; Atasever, 2023). Clays are globally abundant, cost-effective, and mineralogically diverse (Neisser-Deiters et al., 2019 ; Maier et al., 2020; Nawel et al., 2020 ). Their calcination process, which involves dihydroxylation and the development of amorphous phases, imparts pozzolanic reactivity suitable for cement replacement (Almenares et al., 2017 ; Castillo et al., 2010 ; Matias et al., 2014 ). This reactivity is influenced by calcination temperature, duration, and clay composition (Tironi et al., 2012 ). During hydration, calcium hydroxide from cement reacts with the silica and alumina from calcined clay to form calcium silicate hydrate (C-S-H) and other strength-contributing phases (Ilić et al., 2018 ). On the other hand, limestone powder has an essential role in LC3 system both chemically and physically (Ijaz et al., 2023 ). Factors such as the water-to-binder ratio, particle fineness, and curing temperature significantly affect the hydration kinetics (Avet et al., 2018 ). Kaolinite clays typically activate at 400–650°C, forming metakaolin (Avet et al., 2016 ), and Yanguatin et al. ( 2019 ) conducted the compressive strength method at 7 days to evaluate the pozzolanic activity of calcined clay. The optimal level of cement replacement in LC3 depends on the reactivity of the clay. While 50% replacement is common, certain clays may perform better at lower substitution rates. For instance, Gong et al. ( 2022 ) found that LC3-35 outperformed LC3-50 in some cases. The ideal calcined clay-to-limestone (CC:LS) ratio also varies with clay type; Power and Nail (2024) reported optimal CC:LS ratios of 30:15 at 7 days, 35:10 at 28 days, and 25:20 at 56 days. These findings highlight the need for further research into optimizing replacement levels and CC:LS ratios based on the mineral composition of locally sourced clays. Among the various categories of chemical admixtures, Polycarboxylate ether (PCE) has shown greater effectiveness with LC3 compared to other admixtures such as sulfonated naphthalene formaldehyde (SNF), particularly in maintaining slump retention (Long et al., 2021 ; Nair et al., 2020 ). Nevertheless, more investigation is needed to fully understand admixture interactions with LC3 (Ijaz et al., 2023 ). Fiber reinforcement is another area of innovation in cementitious materials. Various fibers—including polypropylene (PP) (Mawlod and Bzeni, 2023 ), carbon (Arai et al., 2019 ), glass (Gao et al., 2018 ), steel (Alomayri et al., 2021 ; Banthia, 1990 ), polyvinyl alcohol (PVA) (Alaloul et al., 2022 ), and basalt (Razzaghian Ghadikolaee et al., 2021 )—are known to enhance concrete performance. Fibers reduce shrinkage, improve stability, and enhance mechanical and durability properties (Heinzle et al., 2009 ; Ganesan and Shivananda, 2000 ; Singh et al., 2001 ). PP fibers are especially attractive due to their corrosion resistance and low cost (Ali et al., 2020 ). Similarly, natural fibers like sheep wool have been evaluated. While higher wool content can reduce compressive and flexural strength (Štirmer et al., 2014 ), studies have also shown improvements in flexural and tensile strength with optimized dosages (Reyadh et al., 2020; Irfan et al., 2021; Alyousef et al., 2020; Wani et al., 2021). Zhu et al. ( 2020 ) demonstrated that PP-reinforced LC3-based engineered cementitious composites (ECCs) are viable and effective. In general, LC3 concrete has shown enhanced durability and longer service life than conventional OPC concrete (Pillai et al., 2019 ; Nguyen et al., 2020 ; Huang et al., 2020 ). Despite significant research on kaolinite-based LC3 (Ahmad et al., 2022; Atasever, 2023; Ayub et al., 2023; Jan et al., 2024a, b; Li et al., 2024 ; Mawlod, 2025), limited studies have focused on non-kaolinite clays and fiber-reinforced LC3 mortars using recycled fibers. This study investigates the feasibility of producing LC3 mortar from locally available clayey soils. It focuses on optimizing the calcination temperature, cement replacement level, CC:LS ratio, and superplasticizer dosage. The fresh, mechanical, and durability properties of LC3-based mortars reinforced with recycled wool and PP fibers are evaluated and compared with those of OPC-based mortar. 2. Experimental Work 2.1 Materials In this study, ordinary Portland cement was gained from the Tasluja cement factory located in the Kurdistan region of Iraq. Raw clay was sourced from the Sheban area. Figure 1 presents the XRD results for both raw clay and calcined clay. Limestone powder was sourced from the Darbandikhan area. Figure 2 illustrates the particle size distribution of calcined clay and limestone powder. River sand sourced locally was utilized. The sieve analysis is presented in Table 1 . Locally sourced river sand was used, and its sieve analysis is provided in Table 1 . Polypropylene fiber of 12 mm in length was obtained from the local market. Recycled sheep wool fiber was gathered as solid waste and subsequently shredded into fibers measuring 12 mm in length Fig. 3 . The physical and mechanical properties of the fibers are shown in Table 2 . Sulphonated naphthalene formaldehyde (SNF) and polycarboxylate ether (PCE) were utilized. They were acquired from Sika Company. Table 1 sieve analysis of fine aggregate Sieve (mm) 9.5 4.75 2.36 1.18 0.6 0.3 0.15 ASTM C33 100 100 − 95 100 − 80 85 − 50 60 − 25 30 − 5 10 − 0 Passing% 100 96 85 75 57 23 5 Table 2 Physical and mechanical properties of fibers Type of Fiber Length (mm) Diameter (µ) Density (g/cm3) Melting point( o C) Tensile strength (MPa) Modulus of Elasticity (GPa) Polypropylene (PP) 12 32 0.91 160 30 7.1 Sheep Wool (Wl) 12 95–130 0.01 n/a 390 2.375 2.2 Mixing and casting The calcined clay, ordinary Portland cement, fine aggregate, and fibers were mixed in a specified ratio in a dry state to achieve a homogeneous mass. Subsequently, water and superplasticizers were incorporated to create a uniform batch, which was then put into molds in two layers, with each layer manually compacted. The mini-slump cone was used to assess the flowability of the fresh mixture. Cubes with dimensions of 50x50x50 mm were utilized for mechanical and durability assessments. Prisms with dimensions of 40x40x160 mm were utilized to perform the flexural strength test. Following a 24-hour period, the molds were removed, and the samples were immersed in water until the day of testing. The majority of the tests were performed at 28 days. Table 3 presents the mix proportions of the batches. Table 3 mix proportion (gr/batch) No, Mix code Cement Wl PP Clay (30%) LS 2:1 Fine aggregate SP (1.5%) w/b 0.40 1 N0 1924 0 0 0 0 5,772 28.86 770 2 NWl1.5 1924 28.9 0 0 0 5,772 28.86 770 3 NPP1 1924 0 19.2 0 0 5,772 28.86 770 4 LC0 1347 0 0 385 192 5,772 28.86 770 5 Wl 0.5 1154 9.6 0 385 192 5,772 28.86 770 6 Wl 1 1154 19.2 0 385 192 5,772 28.86 770 7 Wl 1.5 1154 28.9 0 385 192 5,772 28.86 770 8 PP 0.5 1154 0 9.6 385 192 5,772 28.86 770 9 PP 1 1154 0 19.2 385 192 5,772 28.86 770 10 PP 1.5 1154 0 28.9 385 192 5,772 28.86 770 2.3 Test Process 2.3.1 Calcination of raw clay The raw clay underwent fast calcination due to direct fire exposure at a specified temperature. Temperature was reliably measured using a laser thermometer. Subsequently, the clay attained ambient temperature. Flash calcination was previously used to calcine clay (Claverie et al., 2015 ). 2.3.2 Flow test A mini-slump mold suggested by Okamura and Ouchi ( 2003 ) was employed to evaluate the flowability of the mixture, as illustrated in Fig. 4 . The flow spread is determined by averaging the two diameters and subtracting the diameter of the slump cone's base. 2.3.3 Compressive strength The compressive strength test was performed on the samples according to ASTM C 109 (2008).. In this test, three samples were prepared for each mixture, and their average was employed to assess the samples at each age. To perform this test, a compression device from concrete lab of Raparin university was used as seen in Fig. 5 . 2.3.4 Flexural strength The flexural strength test was conducted in accordance with ASTM C348–18 ( 2018 ) using the three-point loading technique. Three samples per mix were tested, and their average value was given for evaluation. Figure 6 illustrates the specimen during testing. 2.3.5 Splitting tensile strength According to BS 1881 − 117, the splitting tensile strength test was performed on three samples for each mixture, and their average was taken to evaluate the samples. 2.3.6 Fire resistance: Three samples with dimensions 50x50x50 mm were subjected to direct hydrocarbon fire until they attained the necessary temperature for fire resistance evaluation according to ISO 834. The samples were then cooled to room temperature. 2.3.7 Water sorptivity To perform the water sorptivity test in accordance with ASTM C1585 (2011). The samples were initially dried in an oven, and then cooled as directed, and the lower sections of the sample sides were sealed with silicone to prevent water ingress from the sides. The samples were positioned at the edges with a water depth of 3–4 mm. The weights of the samples were measured at various intervals. The measured weight is divided by the base area of the sample and the density of water Eq. 1 to calculate the sorptivity index (S) (Eq. 2 ). Figure 7 illustrates the sorptivity test. $$\:I=\frac{W}{A.\sigma\:}$$ 1 $$\:S=\frac{I}{\surd\:t}$$ 2 Where, I is cumulative water absorption per unit area (mm), W is the weight of absorbed water (g or kg), A is the cross-sectional (base) area of the sample (cm²), \(\:\sigma\:\) is the density of water (typically 1 g/cm³ or 1000 kg/m³), S is the sorptivity, and t is the elapsed time. 2.3.8 Water absorption To perform the water absorption test in accordance with ASTM C642 (2006). The materials were subjected to oven drying to ascertain their dry mass. The samples were subsequently cooled to room temperature; w1 was recorded, followed by immersion in water for 24 hours; thereafter, the samples were wiped, and w2 was measured. The formula utilized to determine water absorption was as follows: Water absorption %= \(\:\frac{(\text{W}2-\text{W}1)}{\text{W}1}\) x100 (Eq. 3) W1: oven dry mass, W2 weight of samples at saturated surface dry state 2.3.9 Porosity The evaluation was conducted in accordance with ASTM C642 (2006). The samples were subjected to oven drying to ascertain their dried mass. The samples were subsequently cooled to room temperature, at which point w1 was recorded. They were then immersed in water for 24 hours, after which they were wiped and w2 was measured. Subsequently, the samples in a saturated surface dry condition were weighed in water to determine the w3. Porosity was calculated using the Eq. 4: Porosity % \(\:=\frac{(\text{W}2-\text{W}1)}{(\text{W}2-\text{W}3)}\) x100 (Eq. 4) Where, W1: oven dry mass, W2 weight of samples at saturated surface dry state, W3 weight of submerged sample 3. Results and Discussion 3.1 Optimization 3.1.1 Calcination Figure 8 illustrates the ratios of the compressive strength of LC3 mortar compared to regular OPC mortar. LC3 was prepared with a replacement level of 50%. The sand-cement ratio and water-binder ratio were established at 3:1 and 0.5, respectively. The proportion of calcined clay to limestone was 2:1. The clay underwent calcination at temperatures of 400˚C, 450˚C, 500˚C, 550˚C, 600˚C, 650˚C, 700˚C, 750˚C, and 800˚C. A compressive strength test was performed at 7 days to evaluate the reactivity of the calcined clay. The compressive strength ratio of LC3 mortar to control samples consistently rises from 0.40 to 0.65, as the calcination temperature increased from 400°C to 650°C consequently. This progressive enhancement in strength can be attributed to the thermal activation of clay minerals which was converted into a metastable condition through dehydroxylation, occurs within this temperature range. Dehydroxylation eleminates structurally bound water, converting crystalline clay into amorphous phase, a highly reactive pozzolanic phase that contributes to strength development when combined with limestone and cement. However, beyond 650˚C, a decline in compressive strength was observed, with the ratio decreasing to 0.58, 0.55, and 0.53. This decline is likely due to the partial recrystallization of the clay structure into stable mineral phases, which are less reactive or even inert in cementitious environments. Moreover, excessive temperatures may cause sintering, reducing the surface area and porosity of the clay particles, thereby diminishing their ability to react with lime Ca(OH)₂ during hydration. These findings are consistent with previous studies (Almenares et al., 2017 ;Overmann et al., 2024 ), which report that the activation temperature of clays is highly dependent on factors such as mineral content, particle size, and degree of crystallinity. 3.1.2 Calcined clay content Figure 9 shows the ratios of the compressive strength of LC3 mortar compared to that of ordinary OPC mortar. LC3 mortar using calcined clay at concentrations of 10%, 20%, 30%, 40%, and 50% was formulated. The sand-cement ratio and water-binder ratio were established at 3:1 and 0.5, respectively. The proportion of calcined clay to limestone was 2:1. The ratio of compressive strength of LC3 mortar to that of control samples consistently rises from 0.85, 0.87, and 0.88 at replacement levels of 10%, 20% and 30%, respectively. When the replacement level increases to 40%, and 50%, the ratio of the compressive strength diminishes to 0.76, and 0.65, respectively. The silica and alumina from the calcined clay combine with calcium hydroxide produced during hydration to generate supplementary gel C-A-S-H. As the replacement level increases to beyond 30%, the strength diminishes due to the restricted interaction between calcined clay constituents and Ca(OH) 2 . Consequently, the ideal replacement ratio for maximizing compressive strength was 30%. Previous research by Gong et al. ( 2022 ) and (Jan et al., 2024a) indicated that LC3-50 is not the optimal replacement level. Gong et al. ( 2022 ) They determined that LC3-35 had superior performance relative to LC3-50. 3.1.3 Calcined clay to Limestone ratio Figure 10 illustrates the ratios of the compressive strength of LC3 mortar compared to regular OPC mortar. LC3 mortar was made with varying calcined clay to limestone ratios of 1:0, 3:1, 2:1, and 1:1. The sand-cement ratio and water-binder ratio were fixed at 3:1 and 0.5, respectively. The optimal replacement level of cement with calcined clay was previously established at 30%. The compressive strength ratio of LC3 mortar to control samples was 0.83, 0.86, 0.88, and 0.79 for CC:LS ratios of 1:0, 3:1, 2:1, and 1:1, respectively. Consequently, the ideal CC:LS ratio was 2:1. Conversely, other writers have observed that the ratio of CC:LS fluctuates based on the nature of the calcined clay minerals, and age of concrete. Power and Naill (2024) examined the various CC:LS ratios. Reports indicated that at 7 and 28 days, the optimal ratios of CC:LS were 30:15 and 35:10, respectively. At 56 days, the optimal ratio was CC:LS 25:20, outperforming LC3-50. 3.1.4 Plasticizer Saturation Dosage Figure 11 illustrates the increasing of flow spread with different dosages of superplasticizer for polycarboxylate ether (PCE) and sulfonated naphthalene formaldehyde (SNF). The slump cone adopted below is the same as that utilized by Okamura and Ouchi ( 2003 ). The mixture was formulated using a sand-binder ratio of 3:1 and a water-binder ratio of 0.35. The ratio of calcined clay to limestone was tuned to 2:1, and the calcined clay replacement level was set at 30%. The constant augmentation of superplasticizer dosage correspondingly enhanced the spread flow. The saturation dosages of PCE and SNF were 2% and 8%, respectively. PCE is demonstrably more effective for the LC3 system than SNF. The saturating dosage of SNF is approximately four times more than that of PCE. This results from the microstructural framework of PCE. Comparable outcomes were attained earlier. Long et al. ( 2021 ) demonstrated that PCE is significantly effective in the LC3 system. The efficacy of the admixture is contingent upon the surface properties of the binder particles, their surface charge, and the chemical composition of the binder. 3.2 Flow test Figure 12 illustrates the change in flow spread with respect to different fiber types and contents. The figure clearly indicates that an increase in fiber content consistently impedes flow spread. Plain and fiber-reinforced OPC mortar has greater flow potential than plain and fiber-reinforced LC3 mortar with equivalent fiber inclusion, likely attributable to the superior compatibility of the PCE superplasticizer with OPC particles compared to LC3 particles. Consequently, for same workability, LC3 necessitates a greater volume of water than OPC. Other authors support this assertion, as LC3 requires additional water to hydration reactions (Ijaz et al., 2023 ). As the fiber content escalated from 0–0.5%, 1%, and 1.5%. WL fiber restricts flowability more than PP fiber. The flow spread of the LC3 mixes reinforced with Wl fiber diminished from 11 cm to 3, 1, and 0 cm. The flow spread of the LC3 mixes reinforced with polypropylene fiber fell from 11 to 4, 1.5, and 0 cm. The fibers create a spatial network that impedes flowability (Mawlod and Bzeni, 2022 ). The difference in limiting flowability between two fiber types may be attributed to the Wl fiber tendency to distribute unifromly within the mixture and obstacle the flowability. Adversly, PP fiber floculates within the mixture. 3.3 Compressive strength Figure 13 illustrates the influence of fiber type and content on the compressive strength of LC3 mortar at 28, 56, and 90 days. The figure indicates that an increase in Wl and PP fiber content in the LC3 mortar marginally enhances compressive strength. The optimal fiber inclusion was 1.5% for Wl fibers and 1% for PP fibers. Wl and PP fibers exhibited comparable efficacy in augmenting the compressive strength of the LC3 mortar. The cause was the bridging of minor shrinkage fractures in the LC3 mortar. Additionally, the compressive strength of plain LC3 mortar is 102%, 91%, and 97% of that of plain OPC mortar at 28 days, 56 days, and 90 days, respectively. Thus, the optimized Wl and PP fiber content of LC3 was compared with the equivalent fiber content of OPC mortar. The incorporation of fiber marginally enhanced the compressive strength of OPC mortar. Fiber inclusion similarly slightly improved the compressive strength of OPC mortar. At 28 days, inclusion of 1.5% of Wl and 1% of PP fibers in LC3 mortar resulted in compressive strengths of 116% and 123%, respectively, compared to the same fiber content in OPC mortar. At 56 days, the optimal incorporation of Wl and PP fibers in LC3 was compared with the equivalent fiber content in OPC mortar. Inclusion of 1.5% Wl and 1% of PP fibers in LC3 mortar exhibited compressive strengths of 97% and 102%, respectively, compared to the same fiber content in OPC mortar. The calcined clay enhances strength development in the LC3 system. In the LC3 system, calcined clay serves both chemical and physical roles. Calcite primarily found in calcined clay and limestone powder (LSP), plays a key role in enhancing the microstructure of the LC3 composite in several different ways. It helps reduce the heat of hydration, minimizing the risk of thermal cracking (Oey et al., 2013). The dilution effect of LSP promotes reactions among LC3 components(Di Salvo Barsi et al., 2020), while calcium ions (Ca²⁺) increase the alkalinity of the pore solution, accelerating C3S hydration(Krishnan et al., 2019). LSP also shortens the dormant phase of OPC reactions (Berodier and Scrivener, 2014). Additionally, the release of carbonate ions from LSP leads to the formation of ettringite and carbo-aluminates, contributing to a denser microstructure(Krishnan et al., 2018). As a result, LC3 mortar exhibits a more compact structure than OPC-based mortar, ensuring stronger fiber–matrix bonding and an improved interferential transition zone. 3.4 Flexural strength Figure 14 depicts the flexural strength values in relation to the fluctuation of fiber type and content in LC3 and OPC mortar, comparing them with lean LC3 and OPC mortar. The increased Wl and PP fiber content in the LC3 mortar enhanced its flexural strength. The optimal fiber incorporation was 1.5% for Wl fibers and 1% for PP fibers. PP fiber shown superior efficiency compared to Wl fiber in improving flexural strength. The flexural strength of plain LC3 mortar is 107% that of plain OPC mortar. Thus, the optimized Wl and PP fiber incorporation of LC3 was compared with the equivalent fiber content in OPC mortar. In LC3 mortar, the introduction of 1% PP and 1.5% Wl fibers resulted in flexural strengths of 108% and 113%, respectively, compared to the equivalent PP and Wl fiber content in OPC mortar. The densified matrix enhances strength and elevates the fiber-matrix interfacial frictional bond, hence augmenting the fiber bridging stress (Zhu et al., 2020 ). Plain LC3 mortar exhibits inferior flexural strength compared to plain OPC mortar. Moreover, fibers markedly enhanced the flexural strength of LC3 mortar. The results align well with the other mechanical properties of LC3 mortar. The microstructure of LC3 mortar is more densified and refined due to the production of extra C-A-S-H gel resulting from the reaction between the active components of calcined clay and Ca(OH) 2 from the hydration process (Avet and Scrivener, 2018 ). Gong et al. ( 2022 ) indicated that the bonding strength and interfacial transition zone are superior than those of OPC mortar. Figure 15 illustrates the specimen following subjected to a three-point stress. The numerous cracks are clearly observable; they serve as evidence of deflection hardening and a high-performance composite (Naaman, 2008 ). 3.5 Splitting tensile strength Figure 16 depicts the splitting tensile strength values in relation to the fiber type and content of LC3 and OPC mortar, contrasting them with plain LC3 and OPC mortar. Increasing Wl and PP fiber content in LC3 mortar enhances tensile strength. The optimal fiber incorporation was 1.5% for Wl fibers and 1% for PP fibers. PP fiber is superior in enhancing tensile strength. This may result from a more uniform distribution of fibers in the fresh state of the mortar. The splitting tensile strength of plain LC3 mortar is 105% that of plain OPC mortar. Thus, the improved Wl and PP fiber incorporation in LC3 was compared to the the same fiber content in OPC mortar. The incorporation of 1% PP and 1.5% Wl fibers in LC3 mortar resulted in tensile strengths of 169% and 163%, respectively, compared to the tensile strength of the same wool and PP fiber content in OPC mortar. The densified matrix enhances strength and elevates the fiber-matrix interfacial frictional bond, hence augmenting the fiber bridging stress (Zhu et al., 2020 ). The microstructure of LC3 mortar is more densified and refined due to the production of extra C-A-S-H gel resulting from the reaction between the active components of calcined clay and Ca(OH) 2 from the hydration process. The binding strength and interfacial transition zone are superior to those of OPC mortar (Avet and Scrivener, 2018 ). (Gong et al., 2022 ); resulting in enhanced tensile strength of the LC3 mortar. Figure 17 illustrates the specimen following subjecting to splitting tensile stress. The numerous crack are clearly evident, serving as proof of strain hardening and the presence of a high-performance composite (Naaman, 2008 ). 3.6 Fire resistance Figure 18 illustrates the compressive strength of plain and fiber-reinforced OPC and LC3 mortars prior to and following exposure to direct fire at temperatures of 400˚C, 500˚C, and 600˚C after 28 days of curing. The increasing amount of Wl and PP fibers in LC3 mortar marginally enhances residual strength. The optimal fiber inclusion was 1.5% for Wl fibers and 1% for PP fibers, respectively. Wl and polypropylene fibers were equally effective in improving the residual strength of the LC3 mortar. From the figure, it is clear that when temperature elevates from ambient to 600°C, the plain LC3 mortar experiences strength loss of 2.54 MPa. While OPC mortar has the highest strength loss, which is 4.27 MPa. That is because of the consumption of Ca(OH) 2 in the LC3 system and converting to gel. At 400, the dehydration C-(A)-S-H showed little effect on the strength, and the decomposition of Ca(OH) 2 will significantly reduce the mechanical properties of the mortar samples (Cao et al., 2023 ). Consequently, the strength loss of fiber-reinforced LC3 is in the range 0.3 to 3.97 MPa. However, strength loss of fiber-reinforced OPC is in the range 3.5 to 4.17 MPa. Fiber-reinforced mortar after exposed to elevated temperature loss strength as the melted fibers make the samples more porous. Conversely, previous researchers indicated that the compressive strength of concrete diminishes significantly after 200°C and experiences substantial loss after 400°C (Caetano et al., 2019 ). Other writers have documented analogous tendencies to those observed in the current study. Gunjal and Kondraivendhan, ( 2022 ) demonstrate that as temperature rises, the drop in compressive strength of M30-LC3 concrete is less significant than that of M30-OPC concrete. This can be elucidated by the dense structure and pozzolanic activity of LC3, along with the combined effect of calcined clay and calcium carbonate (limestone). Their interaction forms carbo-aluminate hydrates, which fill pores and contribute to the increased strength of LC3 concrete (Gunjal and Kondraivendhan, 2022 ). Figure 19 shows the samples after being subjected to elevated temperature. 3.7 Water sorptivity Water sorptivity measures the volume of water that rises through materials via capillary action. This is a crucial examination for evaluating the durability of materials. Figure 20 illustrates the water sorptivity outcomes of plain and fiber-reinforced LC3 and OPC mortar. The sorptivity of ordinary LC3 and OPC mortar is 0.151 mm/min 0.5 and 0.119 mm/min 0.5 , respectively. Thus, the optimum inclusion of 1.5% Wl and 1% PP fibers in LC3 mortar yields sorptivity indices of 0.126mm/min 0.5 and 0.110 mm/min 0.5 respectively, that were compared with the same fiber content of OPC mortar, which are 0.054 mm/min 0.5 and 0.061 mm/min 0.5 , respectively. LC3 has a somewhat analogous microstructure attributable to the filler effect of limestone powder and the pozzolanic reaction, which generates supplementary gel C-A-S-H in addition to the C-S-H gel formed during the conventional hydration process (Avet and Scrivener, 2018 ). This resulted in a reduction of the water sorptivity of the LC3 mortar, making it comparable to OPC mortar. 3.8 Water absorption Water absorption is a critical test that indicates the durability of materials. Figure 21 illustrates the water absorption outcomes of plain and fiber-reinforced LC3 and OPC mortar. The water absorption of both plain and fiber-reinforced LC3 is comparable to that of OPC mortar, ranging from 2.0–2.26%. The water absorption of OPC mortar ranges from 1.34–2.76%. An increase in Wl and PP fiber content in LC3 mortar marginally reduces water absorption. The optimal fiber inclusion was 1.5% for Wl fibers and 1% for PP fibers. Wl and PP fibers were equally effective in reducing the water absorption of LC3 mortar by mitigating minor shrinkage cracks in both plain LC3 and OPC mortars. LC3 has a somewhat equivalent microstructure attributable to the filler effect of limestone powder and the pozzolanic reaction, which generates supplementary gel C-A-S-H in addition to the C-S-H gel formed during the conventional hydration process (Avet and Scrivener, 2018 ). This resulted in a reduction in water absorption in the LC3 mortar, making it comparable to OPC mortar. 3.9 Porosity Figure 22 presents the porosity test outcomes for plain and fiber-reinforced LC3 and OPC mortar. The porosity of fiber-reinforced LC3 closely resembles that of OPC mortar, ranging from 4.5–5.35%. The porosity of OPC mortar ranges from 3.1–5.61%. An increase in Wl and PP fiber content in LC3 mortar marginally reduces porosity. The optimal fiber inclusion was 1.5% for Wl fibers and 1% for PP fibers. Wl and PP fibers shown comparable efficacy in reducing the porosity of LC3 mortar by mitigating minor shrinkage fractures in both plain LC3 and OPC mortars. LC3 has a somewhat similar microstructure attributable to the filler effect of limestone powder and the pozzolanic reaction, which generates supplementary gel C-A-S-H in addition to the C-S-H gel formed during the conventional hydration process (Avet and Scrivener, 2018 ). This resulted in a reduction of the porosity of the LC3 mortar, making it comparable to OPC mortar. 4. Conclusion Based on the comprehensive investigation, the subsequent points can be derived: Locally available non-kaolinite clayey soil can be significantly activated at 650˚C. The LC3 mortar, including 30% calcined clay and limestone, exhibits acceptable mechanical and durability characteristics. The ratio of calcined clay to limestone powder was optimized to 2:1 in this study. PCE is roughly four times as effective as SNF in enhancing the flowability of LC3 mortar. The saturation dosages of PCE and SNF were 2% and 6%, respectively. The flowability of plain and fiber-reinforced OPC mortar exceeded that of plain and reinforced LC3 mortar, respectively. The compressive strength of plain LC3 mortar at 28 days, 56 days, and 90 days was 102%, 91%, and 97% of that of plain OPC mortar, respectively. The incorporation of fiber marginally enhanced compressive strength. Flexural strength and tensile strength of plain LC3 mortar at 28 day was 107% and 105%, respectively, of plain OPC mortar. Fiber incorporation markedly increased the flexural strength and tensile strength of LC3 mortar. The residual strength of plain LC3 mortar exceeded that of plain OPC mortar. The incorporation of fiber marginally increased residual strength. As the temperature increased from 400˚C to 600˚C, the compressive strength experienced a little improvement. The water absorption, sorptivity, and porosity of LC3 mortar were marginally greater than those of OPC mortar. Multiple cracks were distinctly visible throughout the flexural and tensile strength tests, indicating deflection hardening and strain hardening. This experiment demonstrates the possibility of locally accessible clayey soil as a pozzolanic material for the production of LC3. Thus, it demonstrates the potential of utilizing LC3 as a structural material. Declarations Competing interests: The authors declare that there is no conflict of interest. Author Contribution Arass Mawlod: Conceptualisation, Methodology, Investigation, Formal analysis, Validation, Data curation, Visualization,Project administration, Writing—Original Draft. Aram Aziz: Review, Editing, & Schematic figure preparation. 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Mater. 259 , 119805 (2020). Additional Declarations No competing interests reported. Supplementary Files GA.png Cite Share Download PDF Status: Published Journal Publication published 14 Apr, 2026 Read the published version in Scientific Reports → Version 1 posted Editorial decision: Revision requested 25 Aug, 2025 Reviews received at journal 20 Jul, 2025 Reviewers agreed at journal 11 Jul, 2025 Reviews received at journal 16 Jun, 2025 Reviewers agreed at journal 12 Jun, 2025 Reviewers agreed at journal 11 Jun, 2025 Reviewers invited by journal 09 Jun, 2025 Editor assigned by journal 09 Jun, 2025 Editor invited by journal 09 Jun, 2025 Submission checks completed at journal 07 Jun, 2025 First submitted to journal 02 Jun, 2025 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-6804995","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Article","associatedPublications":[],"authors":[{"id":469468205,"identity":"73f05d94-fcfe-438b-8390-b47e197287b7","order_by":0,"name":"Arass Omer 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14","display":"","copyAsset":false,"role":"figure","size":77879,"visible":true,"origin":"","legend":"\u003cp\u003eEffect of fiber type and content on flexural strength of LC3 and OPC mortar\u003c/p\u003e","description":"","filename":"image14.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-6804995/v1/d8961201c1a6f3cbb574f63d.jpeg"},{"id":84401233,"identity":"fe4ad5a9-54a5-4e74-ac81-8c88036ee278","added_by":"auto","created_at":"2025-06-11 13:32:41","extension":"png","order_by":15,"title":"Figure 15","display":"","copyAsset":false,"role":"figure","size":178768,"visible":true,"origin":"","legend":"\u003cp\u003eMultiple cracks at the mid span\u003c/p\u003e","description":"","filename":"image15.png","url":"https://assets-eu.researchsquare.com/files/rs-6804995/v1/e4b6eb519ee732ad362dfe6f.png"},{"id":84401236,"identity":"8e85ac49-12b6-4176-80b2-57188c1710fc","added_by":"auto","created_at":"2025-06-11 13:32:41","extension":"png","order_by":16,"title":"Figure 16","display":"","copyAsset":false,"role":"figure","size":534488,"visible":true,"origin":"","legend":"\u003cp\u003eeffect of fiber type and content on splitting tensile strength of LC3 and OPC mortar\u003c/p\u003e","description":"","filename":"image16.png","url":"https://assets-eu.researchsquare.com/files/rs-6804995/v1/e736fda7ff67e2009cb5524c.png"},{"id":84400675,"identity":"968b70d8-1ad0-4a23-956f-7dc4d9187531","added_by":"auto","created_at":"2025-06-11 13:24:41","extension":"png","order_by":17,"title":"Figure 17","display":"","copyAsset":false,"role":"figure","size":5901895,"visible":true,"origin":"","legend":"\u003cp\u003eMultiple cracks under the tensile load\u003c/p\u003e","description":"","filename":"image17.png","url":"https://assets-eu.researchsquare.com/files/rs-6804995/v1/9db1eaea0d7c9c9fb3ed68fb.png"},{"id":84402276,"identity":"8a2afac4-cdcc-45c1-a56a-3c5f8e2a4e00","added_by":"auto","created_at":"2025-06-11 13:40:41","extension":"png","order_by":18,"title":"Figure 18","display":"","copyAsset":false,"role":"figure","size":1220855,"visible":true,"origin":"","legend":"\u003cp\u003eEffect of fiber type and content on residual strength of LC3 and OPC mortar\u003c/p\u003e","description":"","filename":"image18.png","url":"https://assets-eu.researchsquare.com/files/rs-6804995/v1/4ef05791dfe38ff486ec0c80.png"},{"id":84400699,"identity":"2495ff20-44a3-4c30-b1de-e2ca6ac6fdf9","added_by":"auto","created_at":"2025-06-11 13:24:41","extension":"png","order_by":19,"title":"Figure 19","display":"","copyAsset":false,"role":"figure","size":313437,"visible":true,"origin":"","legend":"\u003cp\u003eSamples subjected to 600˚C, 500˚C, and 400˚C\u003c/p\u003e","description":"","filename":"image19.png","url":"https://assets-eu.researchsquare.com/files/rs-6804995/v1/6219ff0ea76a40beb822e29d.png"},{"id":84401249,"identity":"8a53af1a-32cf-4a89-b421-f9d118cdb321","added_by":"auto","created_at":"2025-06-11 13:32:42","extension":"png","order_by":20,"title":"Figure 20","display":"","copyAsset":false,"role":"figure","size":567967,"visible":true,"origin":"","legend":"\u003cp\u003eeffect of fiber type and content on water sorptivity of LC3 and OPC mortar\u003c/p\u003e","description":"","filename":"image20.png","url":"https://assets-eu.researchsquare.com/files/rs-6804995/v1/36824bb2140d9ddce202da16.png"},{"id":84402273,"identity":"54d1bdd7-3f24-4a1d-b6b7-db894512aa58","added_by":"auto","created_at":"2025-06-11 13:40:41","extension":"jpeg","order_by":21,"title":"Figure 21","display":"","copyAsset":false,"role":"figure","size":76693,"visible":true,"origin":"","legend":"\u003cp\u003eEffect of fiber type and content on water absorption of LC3 and OPC mortar\u003c/p\u003e","description":"","filename":"image21.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-6804995/v1/0a25c37f712ec3e6b8903f30.jpeg"},{"id":84400686,"identity":"41f944f2-b2cb-40ce-b843-c8510af1c8c2","added_by":"auto","created_at":"2025-06-11 13:24:41","extension":"png","order_by":22,"title":"Figure 22","display":"","copyAsset":false,"role":"figure","size":417431,"visible":true,"origin":"","legend":"\u003cp\u003eEffect of fiber type and content on porosity of LC3 and OPC mortar\u003c/p\u003e","description":"","filename":"image22.png","url":"https://assets-eu.researchsquare.com/files/rs-6804995/v1/2d9b73b290d80fbab39cbdf5.png"},{"id":107351029,"identity":"3f4d82d6-3c04-4fdc-bcfd-70fccd1af267","added_by":"auto","created_at":"2026-04-20 16:07:56","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":12609508,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-6804995/v1/04a3cdcd-1b7a-4991-b0e5-5cbdfb883e72.pdf"},{"id":84401235,"identity":"191a09f5-eb80-41ab-97d6-f6214cdac130","added_by":"auto","created_at":"2025-06-11 13:32:41","extension":"png","order_by":1,"title":"","display":"","copyAsset":false,"role":"supplement","size":55709,"visible":true,"origin":"","legend":"","description":"","filename":"GA.png","url":"https://assets-eu.researchsquare.com/files/rs-6804995/v1/c5e1d469bbf9d905273b469c.png"}],"financialInterests":"No competing interests reported.","formattedTitle":"Optimizations on Multi-Mineral Clayey Soil to Develop Limestone Calcined Clay Cement (LC3) Based Composite","fulltext":[{"header":"1. Introduction","content":"\u003cp\u003eThe cement industry is progressively adopting natural pozzolans as supplementary cementitious materials (SCMs) in an effort to adress its environmental impacts. Cement production is highly energy-intensive and is responsible for approximately 7\u0026ndash;8% of global CO₂ emissions (Andrew, \u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e2018\u003c/span\u003e). Incorporating SCMs into cement formulations has proven to be an effective approach to mitigate emissions by up to 40% without sacrificing concrete quality (Skibsted and Snellings, \u003cspan citationid=\"CR47\" class=\"CitationRef\"\u003e2019\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eIn pursuit of more sustainable construction practices, researchers are designing advanced cement blends. One such approach is Limestone Calcined Clay Cement (LC3), which utilizes high proportions of calcined clay and limestone. This blend (LC3) is especially particularly beneficial in regions with limited industrial waste materials like fly ash or slag. Substituting 50% of Ordinary Portland Cement (OPC) with a combination of calcined clay and limestone (LC3-50) has been shown to reduce CO₂ emissions by around 30% (Gettu et al., \u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e2019\u003c/span\u003e; Murray, \u003cspan citationid=\"CR34\" class=\"CitationRef\"\u003e2000\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eThe scarcity of industrial by-products has driven research toward the utilization of locally available clays as alternative SCMs. For instance, Blouch et al. (2023) reported that LC3 produced with low-kaolinite clays can achieve up to 96% of the compressive strength of OPC-based concrete. In addition to kaolinite, other clays such as montmorillonite, illite, and mixed clays have shown pozzolanic potential, particularly when calcined at temperatures ranging from 600\u0026ndash;850\u0026deg;C, these clays yield strength activity indices between 0.70 to 0.76 (Garg and Skibsted, \u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e2014\u003c/span\u003e; Atasever, 2023).\u003c/p\u003e \u003cp\u003eClays are globally abundant, cost-effective, and mineralogically diverse (Neisser-Deiters et al., \u003cspan citationid=\"CR38\" class=\"CitationRef\"\u003e2019\u003c/span\u003e; Maier et al., 2020; Nawel et al., \u003cspan citationid=\"CR37\" class=\"CitationRef\"\u003e2020\u003c/span\u003e). Their calcination process, which involves dihydroxylation and the development of amorphous phases, imparts pozzolanic reactivity suitable for cement replacement (Almenares et al., \u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e2017\u003c/span\u003e; Castillo et al., \u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e2010\u003c/span\u003e; Matias et al., \u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e2014\u003c/span\u003e). This reactivity is influenced by calcination temperature, duration, and clay composition (Tironi et al., \u003cspan citationid=\"CR51\" class=\"CitationRef\"\u003e2012\u003c/span\u003e). During hydration, calcium hydroxide from cement reacts with the silica and alumina from calcined clay to form calcium silicate hydrate (C-S-H) and other strength-contributing phases (Ilić et al., \u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e2018\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eOn the other hand, limestone powder has an essential role in LC3 system both chemically and physically (Ijaz et al., \u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e2023\u003c/span\u003e). Factors such as the water-to-binder ratio, particle fineness, and curing temperature significantly affect the hydration kinetics (Avet et al., \u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e2018\u003c/span\u003e). Kaolinite clays typically activate at 400\u0026ndash;650\u0026deg;C, forming metakaolin (Avet et al., \u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e2016\u003c/span\u003e), and Yanguatin et al. (\u003cspan citationid=\"CR52\" class=\"CitationRef\"\u003e2019\u003c/span\u003e) conducted the compressive strength method at 7 days to evaluate the pozzolanic activity of calcined clay.\u003c/p\u003e \u003cp\u003eThe optimal level of cement replacement in LC3 depends on the reactivity of the clay. While 50% replacement is common, certain clays may perform better at lower substitution rates. For instance, Gong et al. (\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e2022\u003c/span\u003e) found that LC3-35 outperformed LC3-50 in some cases. The ideal calcined clay-to-limestone (CC:LS) ratio also varies with clay type; Power and Nail (2024) reported optimal CC:LS ratios of 30:15 at 7 days, 35:10 at 28 days, and 25:20 at 56 days. These findings highlight the need for further research into optimizing replacement levels and CC:LS ratios based on the mineral composition of locally sourced clays.\u003c/p\u003e \u003cp\u003eAmong the various categories of chemical admixtures, Polycarboxylate ether (PCE) has shown greater effectiveness with LC3 compared to other admixtures such as sulfonated naphthalene formaldehyde (SNF), particularly in maintaining slump retention (Long et al., \u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e2021\u003c/span\u003e; Nair et al., \u003cspan citationid=\"CR36\" class=\"CitationRef\"\u003e2020\u003c/span\u003e). Nevertheless, more investigation is needed to fully understand admixture interactions with LC3 (Ijaz et al., \u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e2023\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eFiber reinforcement is another area of innovation in cementitious materials. Various fibers\u0026mdash;including polypropylene (PP) (Mawlod and Bzeni, \u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e2023\u003c/span\u003e), carbon (Arai et al., \u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e2019\u003c/span\u003e), glass (Gao et al., \u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e2018\u003c/span\u003e), steel (Alomayri et al., \u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e2021\u003c/span\u003e; Banthia, \u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e1990\u003c/span\u003e), polyvinyl alcohol (PVA) (Alaloul et al., \u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e2022\u003c/span\u003e), and basalt (Razzaghian Ghadikolaee et al., \u003cspan citationid=\"CR44\" class=\"CitationRef\"\u003e2021\u003c/span\u003e)\u0026mdash;are known to enhance concrete performance. Fibers reduce shrinkage, improve stability, and enhance mechanical and durability properties (Heinzle et al., \u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e2009\u003c/span\u003e; Ganesan and Shivananda, \u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e2000\u003c/span\u003e; Singh et al., \u003cspan citationid=\"CR46\" class=\"CitationRef\"\u003e2001\u003c/span\u003e). PP fibers are especially attractive due to their corrosion resistance and low cost (Ali et al., \u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2020\u003c/span\u003e). Similarly, natural fibers like sheep wool have been evaluated. While higher wool content can reduce compressive and flexural strength (Štirmer et al., \u003cspan citationid=\"CR50\" class=\"CitationRef\"\u003e2014\u003c/span\u003e), studies have also shown improvements in flexural and tensile strength with optimized dosages (Reyadh et al., 2020; Irfan et al., 2021; Alyousef et al., 2020; Wani et al., 2021).\u003c/p\u003e \u003cp\u003eZhu et al. (\u003cspan citationid=\"CR54\" class=\"CitationRef\"\u003e2020\u003c/span\u003e) demonstrated that PP-reinforced LC3-based engineered cementitious composites (ECCs) are viable and effective. In general, LC3 concrete has shown enhanced durability and longer service life than conventional OPC concrete (Pillai et al., \u003cspan citationid=\"CR42\" class=\"CitationRef\"\u003e2019\u003c/span\u003e; Nguyen et al., \u003cspan citationid=\"CR39\" class=\"CitationRef\"\u003e2020\u003c/span\u003e; Huang et al., \u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e2020\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eDespite significant research on kaolinite-based LC3 (Ahmad et al., 2022; Atasever, 2023; Ayub et al., 2023; Jan et al., 2024a, b; Li et al., \u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e2024\u003c/span\u003e; Mawlod, 2025), limited studies have focused on non-kaolinite clays and fiber-reinforced LC3 mortars using recycled fibers.\u003c/p\u003e \u003cp\u003eThis study investigates the feasibility of producing LC3 mortar from locally available clayey soils. It focuses on optimizing the calcination temperature, cement replacement level, CC:LS ratio, and superplasticizer dosage. The fresh, mechanical, and durability properties of LC3-based mortars reinforced with recycled wool and PP fibers are evaluated and compared with those of OPC-based mortar.\u003c/p\u003e"},{"header":"2. Experimental Work","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003e2.1 Materials\u003c/h2\u003e \u003cp\u003eIn this study, ordinary Portland cement was gained from the Tasluja cement factory located in the Kurdistan region of Iraq. Raw clay was sourced from the Sheban area. Figure\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e presents the XRD results for both raw clay and calcined clay. Limestone powder was sourced from the Darbandikhan area. Figure\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e illustrates the particle size distribution of calcined clay and limestone powder. River sand sourced locally was utilized. The sieve analysis is presented in Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e. Locally sourced river sand was used, and its sieve analysis is provided in Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e.\u003c/p\u003e \u003cp\u003ePolypropylene fiber of 12 mm in length was obtained from the local market. Recycled sheep wool fiber was gathered as solid waste and subsequently shredded into fibers measuring 12 mm in length Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e. The physical and mechanical properties of the fibers are shown in Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e. Sulphonated naphthalene formaldehyde (SNF) and polycarboxylate ether (PCE) were utilized. They were acquired from Sika Company.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\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\u003esieve analysis of fine aggregate\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"8\"\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 \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 \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSieve (mm)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003e9.5\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003e4.75\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003e2.36\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003e1.18\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.6\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c7\"\u003e \u003cp\u003e0.3\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c8\"\u003e \u003cp\u003e0.15\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eASTM C33\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e100\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e100\u0026thinsp;\u0026minus;\u0026thinsp;95\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e100\u0026thinsp;\u0026minus;\u0026thinsp;80\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e85\u0026thinsp;\u0026minus;\u0026thinsp;50\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e60\u0026thinsp;\u0026minus;\u0026thinsp;25\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e30\u0026thinsp;\u0026minus;\u0026thinsp;5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e10\u0026thinsp;\u0026minus;\u0026thinsp;0\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePassing%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e100\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e96\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e85\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e75\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e57\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e23\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e5\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\u003ePhysical and mechanical properties of fibers\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=\"char\" char=\".\" 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=\"char\" char=\".\" 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=\"char\" char=\".\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c7\" colnum=\"7\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eType of Fiber\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eLength (mm)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eDiameter (\u0026micro;)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eDensity (g/cm3)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003eMelting point(\u003csup\u003eo\u003c/sup\u003eC)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c6\"\u003e \u003cp\u003eTensile strength (MPa)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c7\"\u003e \u003cp\u003eModulus of Elasticity (GPa)\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePolypropylene (PP)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e12\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e32\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.91\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e160\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e30\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e7.1\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSheep Wool (Wl)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e12\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e95\u0026ndash;130\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.01\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003en/a\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e390\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e2.375\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 \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec4\" class=\"Section2\"\u003e \u003ch2\u003e2.2 Mixing and casting\u003c/h2\u003e \u003cp\u003eThe calcined clay, ordinary Portland cement, fine aggregate, and fibers were mixed in a specified ratio in a dry state to achieve a homogeneous mass. Subsequently, water and superplasticizers were incorporated to create a uniform batch, which was then put into molds in two layers, with each layer manually compacted. The mini-slump cone was used to assess the flowability of the fresh mixture. Cubes with dimensions of 50x50x50 mm were utilized for mechanical and durability assessments. Prisms with dimensions of 40x40x160 mm were utilized to perform the flexural strength test. Following a 24-hour period, the molds were removed, and the samples were immersed in water until the day of testing. The majority of the tests were performed at 28 days. Table\u0026nbsp;\u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e3\u003c/span\u003e presents the mix proportions of the batches.\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\u003emix proportion (gr/batch)\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"10\"\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=\"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=\"char\" char=\".\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c7\" colnum=\"7\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c8\" colnum=\"8\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c9\" colnum=\"9\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c10\" colnum=\"10\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eNo,\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eMix code\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eCement\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eWl\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003ePP\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c6\"\u003e \u003cp\u003eClay (30%)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c7\"\u003e \u003cp\u003eLS 2:1\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c8\"\u003e \u003cp\u003eFine aggregate\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c9\"\u003e \u003cp\u003eSP (1.5%)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c10\"\u003e \u003cp\u003ew/b\u003c/p\u003e \u003cp\u003e0.40\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eN0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e1924\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e \u003cp\u003e5,772\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c9\"\u003e \u003cp\u003e28.86\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c10\"\u003e \u003cp\u003e770\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eNWl1.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e1924\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e28.9\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e \u003cp\u003e5,772\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c9\"\u003e \u003cp\u003e28.86\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c10\"\u003e \u003cp\u003e770\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eNPP1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e1924\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e19.2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e \u003cp\u003e5,772\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c9\"\u003e \u003cp\u003e28.86\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c10\"\u003e \u003cp\u003e770\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eLC0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e1347\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e385\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e192\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e \u003cp\u003e5,772\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c9\"\u003e \u003cp\u003e28.86\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c10\"\u003e \u003cp\u003e770\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eWl 0.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e1154\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e9.6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e385\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e192\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e \u003cp\u003e5,772\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c9\"\u003e \u003cp\u003e28.86\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c10\"\u003e \u003cp\u003e770\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eWl 1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e1154\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e19.2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e385\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e192\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e \u003cp\u003e5,772\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c9\"\u003e \u003cp\u003e28.86\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c10\"\u003e \u003cp\u003e770\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eWl 1.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e1154\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e28.9\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e385\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e192\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e \u003cp\u003e5,772\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c9\"\u003e \u003cp\u003e28.86\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c10\"\u003e \u003cp\u003e770\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003ePP 0.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e1154\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e9.6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e385\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e192\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e \u003cp\u003e5,772\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c9\"\u003e \u003cp\u003e28.86\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c10\"\u003e \u003cp\u003e770\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e9\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003ePP 1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e1154\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e19.2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e385\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e192\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e \u003cp\u003e5,772\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c9\"\u003e \u003cp\u003e28.86\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c10\"\u003e \u003cp\u003e770\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e10\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003ePP 1.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e1154\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e28.9\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e385\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e192\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e \u003cp\u003e5,772\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c9\"\u003e \u003cp\u003e28.86\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c10\"\u003e \u003cp\u003e770\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec5\" class=\"Section2\"\u003e \u003ch2\u003e2.3 Test Process\u003c/h2\u003e \u003cdiv id=\"Sec6\" class=\"Section3\"\u003e \u003ch2\u003e2.3.1 Calcination of raw clay\u003c/h2\u003e \u003cp\u003eThe raw clay underwent fast calcination due to direct fire exposure at a specified temperature. Temperature was reliably measured using a laser thermometer. Subsequently, the clay attained ambient temperature. Flash calcination was previously used to calcine clay (Claverie et al., \u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e2015\u003c/span\u003e).\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec7\" class=\"Section3\"\u003e \u003ch2\u003e2.3.2 Flow test\u003c/h2\u003e \u003cp\u003eA mini-slump mold suggested by Okamura and Ouchi (\u003cspan citationid=\"CR40\" class=\"CitationRef\"\u003e2003\u003c/span\u003e) was employed to evaluate the flowability of the mixture, as illustrated in Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e. The flow spread is determined by averaging the two diameters and subtracting the diameter of the slump cone's base.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec8\" class=\"Section3\"\u003e \u003ch2\u003e2.3.3 Compressive strength\u003c/h2\u003e \u003cp\u003eThe compressive strength test was performed on the samples according to ASTM C 109 (2008).. In this test, three samples were prepared for each mixture, and their average was employed to assess the samples at each age. To perform this test, a compression device from concrete lab of Raparin university was used as seen in Fig.\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003e.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec9\" class=\"Section3\"\u003e \u003ch2\u003e2.3.4 Flexural strength\u003c/h2\u003e \u003cp\u003eThe flexural strength test was conducted in accordance with ASTM C348\u0026ndash;18 (\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e2018\u003c/span\u003e) using the three-point loading technique. Three samples per mix were tested, and their average value was given for evaluation. Figure\u0026nbsp;\u003cspan refid=\"Fig6\" class=\"InternalRef\"\u003e6\u003c/span\u003e illustrates the specimen during testing.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec10\" class=\"Section3\"\u003e \u003ch2\u003e2.3.5 Splitting tensile strength\u003c/h2\u003e \u003cp\u003eAccording to BS 1881\u0026thinsp;\u0026minus;\u0026thinsp;117, the splitting tensile strength test was performed on three samples for each mixture, and their average was taken to evaluate the samples.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec11\" class=\"Section3\"\u003e \u003ch2\u003e2.3.6 Fire resistance:\u003c/h2\u003e \u003cp\u003eThree samples with dimensions 50x50x50 mm were subjected to direct hydrocarbon fire until they attained the necessary temperature for fire resistance evaluation according to ISO 834. The samples were then cooled to room temperature.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec12\" class=\"Section3\"\u003e \u003ch2\u003e2.3.7 Water sorptivity\u003c/h2\u003e \u003cp\u003eTo perform the water sorptivity test in accordance with ASTM C1585 (2011). The samples were initially dried in an oven, and then cooled as directed, and the lower sections of the sample sides were sealed with silicone to prevent water ingress from the sides. The samples were positioned at the edges with a water depth of 3\u0026ndash;4 mm. The weights of the samples were measured at various intervals. The measured weight is divided by the base area of the sample and the density of water Eq.\u0026nbsp;\u003cspan refid=\"Equ1\" class=\"InternalRef\"\u003e1\u003c/span\u003e to calculate the sorptivity index (S) (Eq.\u0026nbsp;\u003cspan refid=\"Equ2\" class=\"InternalRef\"\u003e2\u003c/span\u003e). Figure\u0026nbsp;\u003cspan refid=\"Fig7\" class=\"InternalRef\"\u003e7\u003c/span\u003e illustrates the sorptivity test.\u003cdiv id=\"Equ1\" class=\"Equation\"\u003e\u003cdiv format=\"TEX\" class=\"mathdisplay\" id=\"FileID_Equ1\" name=\"EquationSource\"\u003e\n$$\\:I=\\frac{W}{A.\\sigma\\:}$$\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$$\\:S=\\frac{I}{\\surd\\:t}$$\u003c/div\u003e\u003cdiv class=\"EquationNumber\"\u003e2\u003c/div\u003e\u003c/div\u003e\u003c/p\u003e \u003cp\u003eWhere, I is cumulative water absorption per unit area (mm), W is the weight of absorbed water (g or kg), A is the cross-sectional (base) area of the sample (cm\u0026sup2;), \u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:\\sigma\\:\\)\u003c/span\u003e\u003c/span\u003e is the density of water (typically 1 g/cm\u0026sup3; or 1000 kg/m\u0026sup3;), S is the sorptivity, and t is the elapsed time.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec13\" class=\"Section3\"\u003e \u003ch2\u003e2.3.8 Water absorption\u003c/h2\u003e \u003cp\u003eTo perform the water absorption test in accordance with ASTM C642 (2006). The materials were subjected to oven drying to ascertain their dry mass. The samples were subsequently cooled to room temperature; w1 was recorded, followed by immersion in water for 24 hours; thereafter, the samples were wiped, and w2 was measured. The formula utilized to determine water absorption was as follows:\u003c/p\u003e \u003cp\u003eWater absorption %=\u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:\\frac{(\\text{W}2-\\text{W}1)}{\\text{W}1}\\)\u003c/span\u003e\u003c/span\u003ex100 (Eq.\u0026nbsp;3)\u003c/p\u003e \u003cp\u003eW1: oven dry mass, W2 weight of samples at saturated surface dry state\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec14\" class=\"Section3\"\u003e \u003ch2\u003e2.3.9 Porosity\u003c/h2\u003e \u003cp\u003eThe evaluation was conducted in accordance with ASTM C642 (2006). The samples were subjected to oven drying to ascertain their dried mass. The samples were subsequently cooled to room temperature, at which point w1 was recorded. They were then immersed in water for 24 hours, after which they were wiped and w2 was measured. Subsequently, the samples in a saturated surface dry condition were weighed in water to determine the w3. Porosity was calculated using the Eq.\u0026nbsp;4:\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"No\" id=\"Taba\" border=\"1\"\u003e \u003ccolgroup cols=\"2\"\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 \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePorosity %\u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:=\\frac{(\\text{W}2-\\text{W}1)}{(\\text{W}2-\\text{W}3)}\\)\u003c/span\u003e\u003c/span\u003e x100\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e(Eq.\u0026nbsp;4)\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\u003eWhere, W1: oven dry mass, W2 weight of samples at saturated surface dry state, W3 weight of submerged sample\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e"},{"header":"3. Results and Discussion","content":"\u003cdiv id=\"Sec16\" class=\"Section2\"\u003e \u003ch2\u003e3.1 Optimization\u003c/h2\u003e \u003cdiv id=\"Sec17\" class=\"Section3\"\u003e \u003ch2\u003e3.1.1 Calcination\u003c/h2\u003e \u003cp\u003eFigure \u003cspan refid=\"Fig8\" class=\"InternalRef\"\u003e8\u003c/span\u003e illustrates the ratios of the compressive strength of LC3 mortar compared to regular OPC mortar. LC3 was prepared with a replacement level of 50%. The sand-cement ratio and water-binder ratio were established at 3:1 and 0.5, respectively. The proportion of calcined clay to limestone was 2:1. The clay underwent calcination at temperatures of 400˚C, 450˚C, 500˚C, 550˚C, 600˚C, 650˚C, 700˚C, 750˚C, and 800˚C. A compressive strength test was performed at 7 days to evaluate the reactivity of the calcined clay. The compressive strength ratio of LC3 mortar to control samples consistently rises from 0.40 to 0.65, as the calcination temperature increased from 400\u0026deg;C to 650\u0026deg;C consequently. This progressive enhancement in strength can be attributed to the thermal activation of clay minerals which was converted into a metastable condition through dehydroxylation, occurs within this temperature range. Dehydroxylation eleminates structurally bound water, converting crystalline clay into amorphous phase, a highly reactive pozzolanic phase that contributes to strength development when combined with limestone and cement. However, beyond 650˚C, a decline in compressive strength was observed, with the ratio decreasing to 0.58, 0.55, and 0.53. This decline is likely due to the partial recrystallization of the clay structure into stable mineral phases, which are less reactive or even inert in cementitious environments. Moreover, excessive temperatures may cause sintering, reducing the surface area and porosity of the clay particles, thereby diminishing their ability to react with lime Ca(OH)₂ during hydration. These findings are consistent with previous studies (Almenares et al., \u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e2017\u003c/span\u003e;Overmann et al., \u003cspan citationid=\"CR41\" class=\"CitationRef\"\u003e2024\u003c/span\u003e), which report that the activation temperature of clays is highly dependent on factors such as mineral content, particle size, and degree of crystallinity.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec18\" class=\"Section3\"\u003e \u003ch2\u003e3.1.2 Calcined clay content\u003c/h2\u003e \u003cp\u003eFigure \u003cspan refid=\"Fig9\" class=\"InternalRef\"\u003e9\u003c/span\u003e shows the ratios of the compressive strength of LC3 mortar compared to that of ordinary OPC mortar. LC3 mortar using calcined clay at concentrations of 10%, 20%, 30%, 40%, and 50% was formulated. The sand-cement ratio and water-binder ratio were established at 3:1 and 0.5, respectively. The proportion of calcined clay to limestone was 2:1. The ratio of compressive strength of LC3 mortar to that of control samples consistently rises from 0.85, 0.87, and 0.88 at replacement levels of 10%, 20% and 30%, respectively. When the replacement level increases to 40%, and 50%, the ratio of the compressive strength diminishes to 0.76, and 0.65, respectively. The silica and alumina from the calcined clay combine with calcium hydroxide produced during hydration to generate supplementary gel C-A-S-H. As the replacement level increases to beyond 30%, the strength diminishes due to the restricted interaction between calcined clay constituents and Ca(OH)\u003csub\u003e2\u003c/sub\u003e. Consequently, the ideal replacement ratio for maximizing compressive strength was 30%. Previous research by Gong et al. (\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e2022\u003c/span\u003e) and (Jan et al., 2024a) indicated that LC3-50 is not the optimal replacement level. Gong et al. (\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e2022\u003c/span\u003e) They determined that LC3-35 had superior performance relative to LC3-50.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec19\" class=\"Section3\"\u003e \u003ch2\u003e3.1.3 Calcined clay to Limestone ratio\u003c/h2\u003e \u003cp\u003eFigure \u003cspan refid=\"Fig10\" class=\"InternalRef\"\u003e10\u003c/span\u003e illustrates the ratios of the compressive strength of LC3 mortar compared to regular OPC mortar. LC3 mortar was made with varying calcined clay to limestone ratios of 1:0, 3:1, 2:1, and 1:1. The sand-cement ratio and water-binder ratio were fixed at 3:1 and 0.5, respectively. The optimal replacement level of cement with calcined clay was previously established at 30%. The compressive strength ratio of LC3 mortar to control samples was 0.83, 0.86, 0.88, and 0.79 for CC:LS ratios of 1:0, 3:1, 2:1, and 1:1, respectively. Consequently, the ideal CC:LS ratio was 2:1. Conversely, other writers have observed that the ratio of CC:LS fluctuates based on the nature of the calcined clay minerals, and age of concrete. Power and Naill (2024) examined the various CC:LS ratios. Reports indicated that at 7 and 28 days, the optimal ratios of CC:LS were 30:15 and 35:10, respectively. At 56 days, the optimal ratio was CC:LS 25:20, outperforming LC3-50.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec20\" class=\"Section3\"\u003e \u003ch2\u003e3.1.4 Plasticizer Saturation Dosage\u003c/h2\u003e \u003cp\u003eFigure \u003cspan refid=\"Fig11\" class=\"InternalRef\"\u003e11\u003c/span\u003e illustrates the increasing of flow spread with different dosages of superplasticizer for polycarboxylate ether (PCE) and sulfonated naphthalene formaldehyde (SNF). The slump cone adopted below is the same as that utilized by Okamura and Ouchi (\u003cspan citationid=\"CR40\" class=\"CitationRef\"\u003e2003\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eThe mixture was formulated using a sand-binder ratio of 3:1 and a water-binder ratio of 0.35. The ratio of calcined clay to limestone was tuned to 2:1, and the calcined clay replacement level was set at 30%.\u003c/p\u003e \u003cp\u003eThe constant augmentation of superplasticizer dosage correspondingly enhanced the spread flow. The saturation dosages of PCE and SNF were 2% and 8%, respectively. PCE is demonstrably more effective for the LC3 system than SNF. The saturating dosage of SNF is approximately four times more than that of PCE. This results from the microstructural framework of PCE. Comparable outcomes were attained earlier. Long et al. (\u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e2021\u003c/span\u003e) demonstrated that PCE is significantly effective in the LC3 system. The efficacy of the admixture is contingent upon the surface properties of the binder particles, their surface charge, and the chemical composition of the binder.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv id=\"Sec21\" class=\"Section2\"\u003e \u003ch2\u003e3.2 Flow test\u003c/h2\u003e \u003cp\u003eFigure \u003cspan refid=\"Fig12\" class=\"InternalRef\"\u003e12\u003c/span\u003e illustrates the change in flow spread with respect to different fiber types and contents. The figure clearly indicates that an increase in fiber content consistently impedes flow spread. Plain and fiber-reinforced OPC mortar has greater flow potential than plain and fiber-reinforced LC3 mortar with equivalent fiber inclusion, likely attributable to the superior compatibility of the PCE superplasticizer with OPC particles compared to LC3 particles. Consequently, for same workability, LC3 necessitates a greater volume of water than OPC. Other authors support this assertion, as LC3 requires additional water to hydration reactions (Ijaz et al., \u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e2023\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eAs the fiber content escalated from 0\u0026ndash;0.5%, 1%, and 1.5%. WL fiber restricts flowability more than PP fiber. The flow spread of the LC3 mixes reinforced with Wl fiber diminished from 11 cm to 3, 1, and 0 cm. The flow spread of the LC3 mixes reinforced with polypropylene fiber fell from 11 to 4, 1.5, and 0 cm. The fibers create a spatial network that impedes flowability (Mawlod and Bzeni, \u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e2022\u003c/span\u003e). The difference in limiting flowability between two fiber types may be attributed to the Wl fiber tendency to distribute unifromly within the mixture and obstacle the flowability. Adversly, PP fiber floculates within the mixture.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec22\" class=\"Section2\"\u003e \u003ch2\u003e3.3 Compressive strength\u003c/h2\u003e \u003cp\u003eFigure \u003cspan refid=\"Fig13\" class=\"InternalRef\"\u003e13\u003c/span\u003e illustrates the influence of fiber type and content on the compressive strength of LC3 mortar at 28, 56, and 90 days. The figure indicates that an increase in Wl and PP fiber content in the LC3 mortar marginally enhances compressive strength. The optimal fiber inclusion was 1.5% for Wl fibers and 1% for PP fibers. Wl and PP fibers exhibited comparable efficacy in augmenting the compressive strength of the LC3 mortar. The cause was the bridging of minor shrinkage fractures in the LC3 mortar.\u003c/p\u003e \u003cp\u003eAdditionally, the compressive strength of plain LC3 mortar is 102%, 91%, and 97% of that of plain OPC mortar at 28 days, 56 days, and 90 days, respectively. Thus, the optimized Wl and PP fiber content of LC3 was compared with the equivalent fiber content of OPC mortar. The incorporation of fiber marginally enhanced the compressive strength of OPC mortar. Fiber inclusion similarly slightly improved the compressive strength of OPC mortar. At 28 days, inclusion of 1.5% of Wl and 1% of PP fibers in LC3 mortar resulted in compressive strengths of 116% and 123%, respectively, compared to the same fiber content in OPC mortar. At 56 days, the optimal incorporation of Wl and PP fibers in LC3 was compared with the equivalent fiber content in OPC mortar. Inclusion of 1.5% Wl and 1% of PP fibers in LC3 mortar exhibited compressive strengths of 97% and 102%, respectively, compared to the same fiber content in OPC mortar.\u003c/p\u003e \u003cp\u003eThe calcined clay enhances strength development in the LC3 system. In the LC3 system, calcined clay serves both chemical and physical roles. Calcite primarily found in calcined clay and limestone powder (LSP), plays a key role in enhancing the microstructure of the LC3 composite in several different ways. It helps reduce the heat of hydration, minimizing the risk of thermal cracking (Oey et al., 2013). The dilution effect of LSP promotes reactions among LC3 components(Di Salvo Barsi et al., 2020), while calcium ions (Ca\u0026sup2;⁺) increase the alkalinity of the pore solution, accelerating C3S hydration(Krishnan et al., 2019). LSP also shortens the dormant phase of OPC reactions (Berodier and Scrivener, 2014). Additionally, the release of carbonate ions from LSP leads to the formation of ettringite and carbo-aluminates, contributing to a denser microstructure(Krishnan et al., 2018). As a result, LC3 mortar exhibits a more compact structure than OPC-based mortar, ensuring stronger fiber\u0026ndash;matrix bonding and an improved interferential transition zone.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec23\" class=\"Section2\"\u003e \u003ch2\u003e3.4 Flexural strength\u003c/h2\u003e \u003cp\u003eFigure \u003cspan refid=\"Fig14\" class=\"InternalRef\"\u003e14\u003c/span\u003e depicts the flexural strength values in relation to the fluctuation of fiber type and content in LC3 and OPC mortar, comparing them with lean LC3 and OPC mortar. The increased Wl and PP fiber content in the LC3 mortar enhanced its flexural strength. The optimal fiber incorporation was 1.5% for Wl fibers and 1% for PP fibers. PP fiber shown superior efficiency compared to Wl fiber in improving flexural strength.\u003c/p\u003e \u003cp\u003eThe flexural strength of plain LC3 mortar is 107% that of plain OPC mortar. Thus, the optimized Wl and PP fiber incorporation of LC3 was compared with the equivalent fiber content in OPC mortar. In LC3 mortar, the introduction of 1% PP and 1.5% Wl fibers resulted in flexural strengths of 108% and 113%, respectively, compared to the equivalent PP and Wl fiber content in OPC mortar. The densified matrix enhances strength and elevates the fiber-matrix interfacial frictional bond, hence augmenting the fiber bridging stress (Zhu et al., \u003cspan citationid=\"CR54\" class=\"CitationRef\"\u003e2020\u003c/span\u003e). Plain LC3 mortar exhibits inferior flexural strength compared to plain OPC mortar. Moreover, fibers markedly enhanced the flexural strength of LC3 mortar. The results align well with the other mechanical properties of LC3 mortar. The microstructure of LC3 mortar is more densified and refined due to the production of extra C-A-S-H gel resulting from the reaction between the active components of calcined clay and Ca(OH)\u003csub\u003e2\u003c/sub\u003e from the hydration process (Avet and Scrivener, \u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e2018\u003c/span\u003e). Gong et al. (\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e2022\u003c/span\u003e) indicated that the bonding strength and interfacial transition zone are superior than those of OPC mortar.\u003c/p\u003e \u003cp\u003eFigure \u003cspan refid=\"Fig15\" class=\"InternalRef\"\u003e15\u003c/span\u003e illustrates the specimen following subjected to a three-point stress. The numerous cracks are clearly observable; they serve as evidence of deflection hardening and a high-performance composite (Naaman, \u003cspan citationid=\"CR35\" class=\"CitationRef\"\u003e2008\u003c/span\u003e).\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec24\" class=\"Section2\"\u003e \u003ch2\u003e3.5 Splitting tensile strength\u003c/h2\u003e \u003cp\u003eFigure \u003cspan refid=\"Fig16\" class=\"InternalRef\"\u003e16\u003c/span\u003e depicts the splitting tensile strength values in relation to the fiber type and content of LC3 and OPC mortar, contrasting them with plain LC3 and OPC mortar. Increasing Wl and PP fiber content in LC3 mortar enhances tensile strength. The optimal fiber incorporation was 1.5% for Wl fibers and 1% for PP fibers. PP fiber is superior in enhancing tensile strength. This may result from a more uniform distribution of fibers in the fresh state of the mortar.\u003c/p\u003e \u003cp\u003eThe splitting tensile strength of plain LC3 mortar is 105% that of plain OPC mortar. Thus, the improved Wl and PP fiber incorporation in LC3 was compared to the the same fiber content in OPC mortar. The incorporation of 1% PP and 1.5% Wl fibers in LC3 mortar resulted in tensile strengths of 169% and 163%, respectively, compared to the tensile strength of the same wool and PP fiber content in OPC mortar.\u003c/p\u003e \u003cp\u003eThe densified matrix enhances strength and elevates the fiber-matrix interfacial frictional bond, hence augmenting the fiber bridging stress (Zhu et al., \u003cspan citationid=\"CR54\" class=\"CitationRef\"\u003e2020\u003c/span\u003e). The microstructure of LC3 mortar is more densified and refined due to the production of extra C-A-S-H gel resulting from the reaction between the active components of calcined clay and Ca(OH)\u003csub\u003e2\u003c/sub\u003e from the hydration process. The binding strength and interfacial transition zone are superior to those of OPC mortar (Avet and Scrivener, \u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e2018\u003c/span\u003e). (Gong et al., \u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e2022\u003c/span\u003e); resulting in enhanced tensile strength of the LC3 mortar.\u003c/p\u003e \u003cp\u003eFigure \u003cspan refid=\"Fig17\" class=\"InternalRef\"\u003e17\u003c/span\u003e illustrates the specimen following subjecting to splitting tensile stress. The numerous crack are clearly evident, serving as proof of strain hardening and the presence of a high-performance composite (Naaman, \u003cspan citationid=\"CR35\" class=\"CitationRef\"\u003e2008\u003c/span\u003e).\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec25\" class=\"Section2\"\u003e \u003ch2\u003e3.6 Fire resistance\u003c/h2\u003e \u003cp\u003eFigure \u003cspan refid=\"Fig18\" class=\"InternalRef\"\u003e18\u003c/span\u003e illustrates the compressive strength of plain and fiber-reinforced OPC and LC3 mortars prior to and following exposure to direct fire at temperatures of 400˚C, 500˚C, and 600˚C after 28 days of curing.\u003c/p\u003e \u003cp\u003eThe increasing amount of Wl and PP fibers in LC3 mortar marginally enhances residual strength. The optimal fiber inclusion was 1.5% for Wl fibers and 1% for PP fibers, respectively. Wl and polypropylene fibers were equally effective in improving the residual strength of the LC3 mortar.\u003c/p\u003e \u003cp\u003eFrom the figure, it is clear that when temperature elevates from ambient to 600\u0026deg;C, the plain LC3 mortar experiences strength loss of 2.54 MPa. While OPC mortar has the highest strength loss, which is 4.27 MPa. That is because of the consumption of Ca(OH)\u003csub\u003e2\u003c/sub\u003e in the LC3 system and converting to gel. At 400, the dehydration C-(A)-S-H showed little effect on the strength, and the decomposition of Ca(OH)\u003csub\u003e2\u003c/sub\u003e will significantly reduce the mechanical properties of the mortar samples (Cao et al., \u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e2023\u003c/span\u003e). Consequently, the strength loss of fiber-reinforced LC3 is in the range 0.3 to 3.97 MPa. However, strength loss of fiber-reinforced OPC is in the range 3.5 to 4.17 MPa. Fiber-reinforced mortar after exposed to elevated temperature loss strength as the melted fibers make the samples more porous.\u003c/p\u003e \u003cp\u003eConversely, previous researchers indicated that the compressive strength of concrete diminishes significantly after 200\u0026deg;C and experiences substantial loss after 400\u0026deg;C (Caetano et al., \u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e2019\u003c/span\u003e). Other writers have documented analogous tendencies to those observed in the current study. Gunjal and Kondraivendhan, (\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e2022\u003c/span\u003e) demonstrate that as temperature rises, the drop in compressive strength of M30-LC3 concrete is less significant than that of M30-OPC concrete.\u003c/p\u003e \u003cp\u003eThis can be elucidated by the dense structure and pozzolanic activity of LC3, along with the combined effect of calcined clay and calcium carbonate (limestone). Their interaction forms carbo-aluminate hydrates, which fill pores and contribute to the increased strength of LC3 concrete (Gunjal and Kondraivendhan, \u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e2022\u003c/span\u003e). Figure\u0026nbsp;\u003cspan refid=\"Fig19\" class=\"InternalRef\"\u003e19\u003c/span\u003e shows the samples after being subjected to elevated temperature.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec26\" class=\"Section2\"\u003e \u003ch2\u003e3.7 Water sorptivity\u003c/h2\u003e \u003cp\u003eWater sorptivity measures the volume of water that rises through materials via capillary action. This is a crucial examination for evaluating the durability of materials. Figure\u0026nbsp;\u003cspan refid=\"Fig20\" class=\"InternalRef\"\u003e20\u003c/span\u003e illustrates the water sorptivity outcomes of plain and fiber-reinforced LC3 and OPC mortar.\u003c/p\u003e \u003cp\u003eThe sorptivity of ordinary LC3 and OPC mortar is 0.151 mm/min\u003csup\u003e0.5\u003c/sup\u003e and 0.119 mm/min\u003csup\u003e0.5\u003c/sup\u003e, respectively. Thus, the optimum inclusion of 1.5% Wl and 1% PP fibers in LC3 mortar yields sorptivity indices of 0.126mm/min\u003csup\u003e0.5\u003c/sup\u003e and 0.110 mm/min\u003csup\u003e0.5\u003c/sup\u003e respectively, that were compared with the same fiber content of OPC mortar, which are 0.054 mm/min\u003csup\u003e0.5\u003c/sup\u003e and 0.061 mm/min\u003csup\u003e0.5\u003c/sup\u003e, respectively.\u003c/p\u003e \u003cp\u003eLC3 has a somewhat analogous microstructure attributable to the filler effect of limestone powder and the pozzolanic reaction, which generates supplementary gel C-A-S-H in addition to the C-S-H gel formed during the conventional hydration process (Avet and Scrivener, \u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e2018\u003c/span\u003e). This resulted in a reduction of the water sorptivity of the LC3 mortar, making it comparable to OPC mortar.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec27\" class=\"Section2\"\u003e \u003ch2\u003e3.8 Water absorption\u003c/h2\u003e \u003cp\u003eWater absorption is a critical test that indicates the durability of materials. Figure\u0026nbsp;\u003cspan refid=\"Fig21\" class=\"InternalRef\"\u003e21\u003c/span\u003e illustrates the water absorption outcomes of plain and fiber-reinforced LC3 and OPC mortar. The water absorption of both plain and fiber-reinforced LC3 is comparable to that of OPC mortar, ranging from 2.0\u0026ndash;2.26%. The water absorption of OPC mortar ranges from 1.34\u0026ndash;2.76%. An increase in Wl and PP fiber content in LC3 mortar marginally reduces water absorption. The optimal fiber inclusion was 1.5% for Wl fibers and 1% for PP fibers. Wl and PP fibers were equally effective in reducing the water absorption of LC3 mortar by mitigating minor shrinkage cracks in both plain LC3 and OPC mortars.\u003c/p\u003e \u003cp\u003eLC3 has a somewhat equivalent microstructure attributable to the filler effect of limestone powder and the pozzolanic reaction, which generates supplementary gel C-A-S-H in addition to the C-S-H gel formed during the conventional hydration process (Avet and Scrivener, \u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e2018\u003c/span\u003e). This resulted in a reduction in water absorption in the LC3 mortar, making it comparable to OPC mortar.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec28\" class=\"Section2\"\u003e \u003ch2\u003e3.9 Porosity\u003c/h2\u003e \u003cp\u003eFigure \u003cspan refid=\"Fig22\" class=\"InternalRef\"\u003e22\u003c/span\u003e presents the porosity test outcomes for plain and fiber-reinforced LC3 and OPC mortar. The porosity of fiber-reinforced LC3 closely resembles that of OPC mortar, ranging from 4.5\u0026ndash;5.35%. The porosity of OPC mortar ranges from 3.1\u0026ndash;5.61%. An increase in Wl and PP fiber content in LC3 mortar marginally reduces porosity. The optimal fiber inclusion was 1.5% for Wl fibers and 1% for PP fibers. Wl and PP fibers shown comparable efficacy in reducing the porosity of LC3 mortar by mitigating minor shrinkage fractures in both plain LC3 and OPC mortars.\u003c/p\u003e \u003cp\u003eLC3 has a somewhat similar microstructure attributable to the filler effect of limestone powder and the pozzolanic reaction, which generates supplementary gel C-A-S-H in addition to the C-S-H gel formed during the conventional hydration process (Avet and Scrivener, \u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e2018\u003c/span\u003e). This resulted in a reduction of the porosity of the LC3 mortar, making it comparable to OPC mortar.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e"},{"header":"4. Conclusion","content":"\u003cp\u003e \u003cdiv class=\"BlockQuote\"\u003e \u003cp\u003eBased on the comprehensive investigation, the subsequent points can be derived:\u003c/p\u003e \u003c/div\u003e \u003c/p\u003e \u003cp\u003e \u003cul\u003e \u003cli\u003e \u003cp\u003eLocally available non-kaolinite clayey soil can be significantly activated at 650˚C.\u003c/p\u003e \u003c/li\u003e \u003cli\u003e \u003cp\u003eThe LC3 mortar, including 30% calcined clay and limestone, exhibits acceptable mechanical and durability characteristics.\u003c/p\u003e \u003c/li\u003e \u003cli\u003e \u003cp\u003eThe ratio of calcined clay to limestone powder was optimized to 2:1 in this study.\u003c/p\u003e \u003c/li\u003e \u003cli\u003e \u003cp\u003ePCE is roughly four times as effective as SNF in enhancing the flowability of LC3 mortar. The saturation dosages of PCE and SNF were 2% and 6%, respectively.\u003c/p\u003e \u003c/li\u003e \u003cli\u003e \u003cp\u003eThe flowability of plain and fiber-reinforced OPC mortar exceeded that of plain and reinforced LC3 mortar, respectively.\u003c/p\u003e \u003c/li\u003e \u003cli\u003e \u003cp\u003eThe compressive strength of plain LC3 mortar at 28 days, 56 days, and 90 days was 102%, 91%, and 97% of that of plain OPC mortar, respectively. The incorporation of fiber marginally enhanced compressive strength.\u003c/p\u003e \u003c/li\u003e \u003cli\u003e \u003cp\u003eFlexural strength and tensile strength of plain LC3 mortar at 28 day was 107% and 105%, respectively, of plain OPC mortar. Fiber incorporation markedly increased the flexural strength and tensile strength of LC3 mortar.\u003c/p\u003e \u003c/li\u003e \u003cli\u003e \u003cp\u003eThe residual strength of plain LC3 mortar exceeded that of plain OPC mortar. The incorporation of fiber marginally increased residual strength. As the temperature increased from 400˚C to 600˚C, the compressive strength experienced a little improvement.\u003c/p\u003e \u003c/li\u003e \u003cli\u003e \u003cp\u003eThe water absorption, sorptivity, and porosity of LC3 mortar were marginally greater than those of OPC mortar.\u003c/p\u003e \u003c/li\u003e \u003cli\u003e \u003cp\u003eMultiple cracks were distinctly visible throughout the flexural and tensile strength tests, indicating deflection hardening and strain hardening.\u003c/p\u003e \u003c/li\u003e \u003c/ul\u003e \u003cdiv class=\"BlockQuote\"\u003e \u003cp\u003eThis experiment demonstrates the possibility of locally accessible clayey soil as a pozzolanic material for the production of LC3. Thus, it demonstrates the potential of utilizing LC3 as a structural material.\u003c/p\u003e \u003c/div\u003e \u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e \u003ch2\u003eCompeting interests:\u003c/h2\u003e \u003cp\u003eThe authors declare that there is no conflict of interest.\u003c/p\u003e \u003c/p\u003e\u003ch2\u003eAuthor Contribution\u003c/h2\u003e\u003cp\u003eArass Mawlod: Conceptualisation, Methodology, Investigation, Formal analysis, Validation, Data curation, Visualization,Project administration, Writing\u0026mdash;Original Draft. Aram Aziz: Review, Editing, \u0026amp; Schematic figure preparation.\u003c/p\u003e\u003ch2\u003eData Availability\u003c/h2\u003e\u003cp\u003eAll of the data will be available on request. First author can be contacted.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eAlaloul, W. S. et al. 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Mater.\u003c/em\u003e \u003cb\u003e259\u003c/b\u003e, 119805 (2020).\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"scientific-reports","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"scirep","sideBox":"Learn more about [Scientific Reports](http://www.nature.com/srep/)","snPcode":"","submissionUrl":"","title":"Scientific Reports","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Scientific Reports","inReviewEnabled":true,"inReviewRevisionsEnabled":true},"keywords":"LC3, calcined clay, flowability, splitting tensile strength, fire resistance","lastPublishedDoi":"10.21203/rs.3.rs-6804995/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-6804995/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eThe cement industry plays a significant role in contributing to global carbon dioxide emissions, representing a considerable portion of the total environmental impact. In response to growing environmental concerns, supplementary cementitious materials such as calcined clay and limestone have gained prominence due to their abundance and reduced carbon footprint. Among these, Limestone Calcined Clay Cement (LC3) has emerged as a promising sustainable alternative to ordinary Portland cement (OPC). This study investigates the feasibility of utilizing locally available non-kaolinitic clayey soil in the development of LC3-based binders. The research was conducted in two phases: initially, the optimum calcination temperature, substitution level of calcined clay, and calcined clay-to-limestone ratio (CC:LS) were determined, yielding optimal values of 650\u0026deg;C, 30%, and 2:1, respectively. Subsequently, the optimal binder compositions were reinforced with recycled sheep wool (Wl) and polypropylene (PP) fibers at varying dosages of 0%, 0.5%, 1%, and 1.5% by binder weight. Fresh mortar flowability was assessed, followed by evaluation of mechanical properties including compressive strength, flexural strength, and splitting tensile strength. Durability parameters such as fire resistance, water absorption, water sorptivity, and porosity were also examined. The results indicated that fiber additions of 1.5% Wl and 1% PP offered the best balance of mechanical performance and durability. However, increasing fiber content consistently reduced flowability. Overall, the findings demonstrate the viability of using locally sourced clayey soil as a pozzolanic material in LC3 production and highlight LC3 potential as a sustainable structural material.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e","manuscriptTitle":"Optimizations on Multi-Mineral Clayey Soil to Develop Limestone Calcined Clay Cement (LC3) Based Composite","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-06-11 13:24:35","doi":"10.21203/rs.3.rs-6804995/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2025-08-25T13:10:05+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-07-20T11:07:39+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"292221313542147589959511768084868721283","date":"2025-07-11T12:41:47+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-06-16T09:25:37+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"268303823503094498559683581382916418186","date":"2025-06-13T01:01:17+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"15806993095873169295230402384914130853","date":"2025-06-12T03:20:21+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2025-06-10T03:18:23+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2025-06-10T03:09:09+00:00","index":"","fulltext":""},{"type":"editorInvited","content":"","date":"2025-06-10T03:05:11+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2025-06-07T16:53:15+00:00","index":"","fulltext":""},{"type":"submitted","content":"Scientific Reports","date":"2025-06-02T19:58:49+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"scientific-reports","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"scirep","sideBox":"Learn more about [Scientific Reports](http://www.nature.com/srep/)","snPcode":"","submissionUrl":"","title":"Scientific Reports","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Scientific Reports","inReviewEnabled":true,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"c856a9ad-2d3f-4cd3-bd7f-d5224cbc47a0","owner":[],"postedDate":"June 11th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"published-in-journal","subjectAreas":[{"id":49846621,"name":"Physical sciences/Engineering/Civil engineering"},{"id":49846622,"name":"Biological sciences/Ecology"},{"id":49846623,"name":"Physical sciences/Materials science"}],"tags":[],"updatedAt":"2026-04-20T16:05:26+00:00","versionOfRecord":{"articleIdentity":"rs-6804995","link":"https://doi.org/10.1038/s41598-026-48577-1","journal":{"identity":"scientific-reports","isVorOnly":false,"title":"Scientific Reports"},"publishedOn":"2026-04-14 15:59:25","publishedOnDateReadable":"April 14th, 2026"},"versionCreatedAt":"2025-06-11 13:24:35","video":"","vorDoi":"10.1038/s41598-026-48577-1","vorDoiUrl":"https://doi.org/10.1038/s41598-026-48577-1","workflowStages":[]},"version":"v1","identity":"rs-6804995","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-6804995","identity":"rs-6804995","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}