Durability Performance of Opc and Lc 3 -50 Concrete Containing Lightweight Aggregates

Durability Performance of Opc and Lc 3 -50 Concrete Containing Lightweight Aggregates | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Durability Performance of Opc and Lc 3 -50 Concrete Containing Lightweight Aggregates Syed Muhammad Fahad Hussain, Tehmina Ayub, Tariq Jamil, Asad -ur-Rehman Khan This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-5658989/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 12 Mar, 2025 Read the published version in Iranian Journal of Science and Technology, Transactions of Civil Engineering → Version 1 posted 24 You are reading this latest preprint version Abstract This study investigates the durability properties of OPC and LC 3 -50 concretes containing shale as lightweight coarse aggregates acquired from the Balochistan Province of Pakistan for structural concrete in comparison to natural coarse aggregates. The physical properties of shale aggregates were initially assessed by performing crushing value, absorption, Impact value tests and specific gravity. In this study, two replacements for lightweight aggregate (0% and 100%) were investigated in OPC and LC 3 -50 concretes, which showed that the use of 100% lightweight in OPC and LC 3 -50-based concretes reduced compressive strength and splitting tensile strength by 60–65% and 25–30% in comparison to natural coarse aggregates without exposure to CO 2 . The reduction in the compressive and splitting tensile strengths due to CO 2 exposure was more OPC than LC 3 -50 concrete due to dense microstructure, which is also evident by the permeability results. The effect of CO 2 in reducing compressive and splitting tensile strengths at later ages (i.e. 270 and 365 days) becomes less than 90 and 180 days. The pull-out strength of OPC and LC 3 -50 concretes is almost similar at 7 and 28 days; however, the 28-day pull-out strength was observed to be 3 times higher than 7 days. Similarly, the permeability of LC 3 -50 concrete is better than OPC. Therefore, it can be concluded that LC 3 -50 in concrete improves durability and can be suitably used with 100% lightweight. 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 1. Introduction In recent years, there has been a growing interest in developing innovative construction materials that reduce the environmental impact of construction activities and exhibit enhanced performance characteristics. Green concrete is being used to produce sustainable infrastructure, which has caught the attention of stakeholders in construction and structural design. The population of the globe has expanded due to the global economic crisis, which has led to an increase in construction waste production and the development of innovative, energy-efficient building techniques for sustainable structures, among other things [ 1 ]. All around the world, cement is used as the main building material for constructing buildings and other infrastructure [ 2 – 4 ]. The expanding demand in the building industry has resulted in a significant growth in cement consumption globally over time. Over 10 billion cubic meters of concrete are produced annually worldwide, and this number is not anticipated to decline [ 5 , 6 ]. There is significant carbon dioxide (CO 2 ) emissions into the atmosphere throughout the OPC production process. The cement industry is thought to be responsible for between 5 and 8% of the world's CO 2 emissions caused by human activity [ 7 ]. It is projected that worldwide CO 2 emissions will surpass those of pre-industrial levels by 2028, leading to an increase in global warming of over 1.5 o C [ 8 ]. The clinkerization and grinding stages of the OPC manufacturing process are the most expensive since they require a large amount of fuel energy [ 9 ]. Consequently, numerous consumers in underdeveloped nations cannot afford Portland cement [ 10 ]. Globally, the primary focus is on achieving the targets for sustainable growth and reducing the carbon footprint associated with the cement manufacturing process. Reducing the amount of clinker in cement is becoming increasingly important in the construction industry [ 11 ]. For this reason, replacing suitable materials like limestone and calcined clay for the clinker in Portland cement can help reduce its amount. In the process of making cement, this lowers CO 2 emissions and total production costs [ 12 ]. A new type of blended cement made of limestone and calcined clay, known as limestone calcined clay cement (LC 3 -50), has 50% less clinker. Compared to ordinary cement, the CO 2 emissions are reduced to 30% with this 50% clinker reduction in LC 3 -50 [ 13 ]. Furthermore, it has been observed that practical concretes employing LC 3 -50 can be produced without requiring substantial modifications to the conventional method of mixture design, even in the face of the highly variable structures of the clay particles. Along with many other benefits, LC 3 -50 outperforms OPC in terms of durability. Alkali-silica reaction (ASR), steel corrosion, sulfate assault, and chloride intrusion are all prevented by it. Previous studies explore the durability aspects of Limestone Calcined Clay Cement (LC 3 -50) and its properties. Scrivener et al. [ 14 ] investigate the carbonation rate of LC 3 -50 and OPC mortars after 3 and 28-day curing periods, noting the significance of calcium oxide (CaO) in regulating carbonation. Thorough curing enhances carbonation resistance, influenced by environmental humidity levels. Li and Ye [ 15 ] analyzed LC 3 -50 paste's carbonation resistance, finding it lower than OPC paste, with carbonation depth ranging from 2.4 to 4.5 mm in 23 weeks. Huang et al. [ 16 ] studied bond behavior between LC 3 -50 concrete and steel rebar, showing a linear increase in bond strength with compressive strength and the impact of rebar diameter on bond stress. As the construction sector seeks innovative materials to reduce its environmental footprint and enhance performance one material that is receiving a lot of attention is lightweight concrete, which is made of shale as a lightweight aggregate. Shale, a sedimentary rock that forms when fine-grained mineral and organic particles are compacted, has shown great potential as a building material, especially when it comes to lightweight concrete. In the search for high-performance and environmentally friendly building materials, shale presents a strong alternative to conventional aggregates because of its unique physical and chemical characteristics and wide availability [ 17 ]. Shale is made up of thinly arranged particles that have a relatively low density and maintain structural integrity. This property works well to develop building materials that are both strong and lightweight [ 18 ]. Its composition often includes minerals like clay, quartz, and various silicates, contributing to its potential as a suitable aggregate in concrete mixtures [ 19 ]. Furthermore, the availability of shale in a variety of geological formations across several countries offers a sustainable substitute for conventional aggregate sources, reducing concerns about resource depletion and emissions from transportation. Using lightweight aggregates, scarce studies are reported in the literature. The study reported by Lo et al. [ 20 ] compares the carbonation effects between lightweight concrete (LWC) and normal-weight concrete (NWC) with similar strength levels. Various binders and aggregates were used to investigate concrete behavior. The carbonation depth was measured after exposing concrete cubes to CO 2 gas under different curing conditions. Results indicate that carbonation depth increases with a higher water-to-binder (w/b) ratio and lower binder content. LWC generally exhibited lower carbonation compared to NWC, attributed partly to NWC's lower cement concentration. The investigation by Teo et al. [ 21 ] focused on the structural bond and durability properties of lightweight concrete using oil palm shells as a lightweight aggregate. The bond strength test on reinforcing bars with varying diameters was conducted under different curing conditions. Bond strength varied based on curing conditions and bar size, with deformed bars in full water curing providing the highest bond strength. Larger bar sizes led to reduced bond strength due to decreased confining pressure from the surrounding concrete. Under carbonation effects, the compressive and split tensile strengths of lightweight concrete using OPC and LC 3 as binders have not yet been investigated. This study addresses this gap by evaluating the durability of lightweight aggregate concrete prepared with Ordinary Portland Cement (OPC) and LC 3 -50. Two replacements for lightweight aggregate (0% and 100%) were investigated. The durability evaluation included the effect of carbonation on compressive strength and split tensile strength, pull-out strength, water permeability, and sorptivity. 2. Material & Methods 2.1 Raw Materials In this study, 53-grade Ordinary Portland Cement (OPC) and Limestone Calcined Clay Cement (LC 3 -50) were used. LC 3 -50 was produced by combining materials in specific proportions: 50% clinker, 30% clay, 15% limestone, and 5% gypsum, all measured by mass. First, the clay was calcined at about 800ºC. It was then mixed with clinker that had been calcined at around 1500ºC. This procedure required the use of clay that was enhanced with a significant amount of kaolin minerals more than 40%. To determine the kaolinite concentration of clay, thermogravimetric (TG) analysis was performed. Based on the mass loss (𝑚 𝑙𝑜𝑠𝑠 ) between 400 and 600 o C using the TG tangent method, the kaolinite content was calculated [ 22 ]. For this study, calcined clay was provided by an industrial facility at Nagarparkar, Tharparkar, Sindh. In an electric furnace, the clay was calcined at 800°C for over an hour. As a result, after being calcined at 800°C, the clay becomes reactive [ 14 ]. The chemical composition of calcined clay, OPC, Limestone, and LC 3 -50 is mentioned in Table 1 . The gypsum within this setup was fine-tuned to promote the progression of the aluminates' reaction (derived from calcined clay) beyond the primary calcium silicate reaction, as observed in isothermal calorimetry [ 23 ]. The particle size distribution of OPC, calcined clay, limestone, and LC 3 -50 by laser diffraction is given in Fig. 1 . The project utilizes locally sourced coarse and fine aggregates. To prevent voids in the concrete, a mix design incorporating a combination of 10 mm and 16 mm coarse aggregates was employed. The fine aggregate was sieved using a 4.75 mm mesh. The reactivity of the pozzolana increases, leading to a need for more water to generate a secondary gel phase [ 24 ]. For enhancing concrete performance in terms of workability and early strength, ViscoCrete-3110, a third-generation superplasticizer is used [ 25 ]. The appropriate dosage of the superplasticizer is crucial to achieve the desired hydration content in the concrete due to the fine nature of the calcined clay, which necessitates additional water. The shale was used as a lightweight aggregate (refer to Fig. 2 ). The raw shale is extracted from the local site of Baluchistan located near Lasbela. The raw shale was bloated at 1000 o C through an electric furnace. The chemical composition is also given in Table 1 . The physical characteristics of shale were assessed through physical testing of the aggregates, and Table 2 provides details on the aggregate's physical properties. Specific gravity and water absorption of lightweight aggregates were determined following ASTM C127-15 [ 26 ] guidelines, while the crushing value and impact value were determined according to BS 812 − 110 [ 27 ] and ASTM C131-20 [ 28 ] standards, respectively. The crushing value and water absorption percentage of lightweight aggregates deviate from the recommended limits, likely attributable to the porous nature of shale. Conversely, the values for impact strength and specific gravity are within the specified range. Table 1 Chemical composition of ordinary Portland cement (OPC), Calcined Clay, Limestone, LC 3 -50, and Shale Oxides Oxides Content (%) Ordinary Portland Cement (OPC) Calcined Clay Limestone Limestone Calcined Clay (LC 3 -50) Shale CaO 61.17 2.29 54.6 34.5 4.03 SiO2 18.47 41.61 0.02 22 70.1 Al2O3 4.28 33.8 0.04 12 8.83 Fe2O3 4.77 0.48 0.05 1.72 4.49 MgO 1.51 0.35 0.15 0.93 0.74 Na2O 0.1 0.1 0.01 0.13 0.19 K2O 0.54 0.06 0 0.4 1.65 SO3 2.6 0.01 0.03 3.12 0.05 Others 6.56 21.3 45.1 25.2 9.92 Table 2 Physical properties of lightweight aggregate Physical Properties Crushing Value Specific Gravity Absorption Impact Value Test Results 53% 2.3 9% 49% Standard Range (%) < 30 [ 27 ] 2.4-3 [ 26 ] 0.1-2 [ 26 ] < 45 [ 28 ] 2.2 Mix Design The design mix was trialed to achieve a target strength of 55.5 MPa (8000 psi) at 28 days, following the guidelines of ACI Committee 363 − 10 [ 29 ]. The ratio of cement to water was maintained at 0.32 during the casting procedure. The remaining volume was divided into a 60:40 ratio of fine and coarse aggregates using a volumetric mix design. In addition, a 30:70 blend of coarse aggregates made of 10 mm and 16 mm aggregates was used. A superplasticizer (SP) was added to the concrete at a dosage of 1.6% in proportion to the cement quantity to improve workability and achieve the requisite 180 mm slump. The durability properties of both OPC and LC 3 -50 concrete were tested using the mix design shown in Table 3 . The raw materials were carefully mixed in a pan mixer operating at 25 revolutions per minute. Ordinary Portland Cement (OPC) is denoted by the letter "O" in the "OL" concrete mix, while "Lightweight aggregates" is denoted by the letter "L" in Table 3 's nomenclature. Similarly, in the "LL" concrete mix, "L" represents the LC 3 -50 blend, and "L" still refers to "Lightweight aggregates". The percentage of light-weight aggregate used for replacement is indicated by the number following the hyphen. The dimensions of the test samples and the duration of their curing and exposure is presented in Table 4 . All the specimens investigated in this research were cast using two different types of binders: Ordinary Portland Cement (OPC) and LC 3 -50. Table 3 Mix design of OPC and LC 3 -50 concrete Materials Mix ID OL-00 OL-100 LL-0 LL-100 OPC 728 728 - - LC 3 -50 - - 728 728 Silica Fumes 51 51 51 51 Water- Binder Ratio 0.32 0.32 0.32 0.32 Natural Aggregates 815 - 815 - Lightweight Aggregates (Shale) - 815 - 815 Fine Aggregates 1099 1099 1099 1099 Super-Plasticizer 1.60% 1.60% 1.60% 1.60% Table 4 Summary of the specimen along with the size and exposure/curing period Tests Cylinder Size Exposer/Curing Days Mix ID OL-00 OL-100 LL-00 LL-100 Compression 100 mm dia. × 200 mm height 90 3 3 3 3 180 3 3 3 3 270 3 3 3 3 365 3 3 3 3 Splitting Tensile 100 mm dia. × 200 mm height 90 3 3 3 3 180 3 3 3 3 270 3 3 3 3 365 3 3 3 3 Pull-out Test 100 mm dia. × 200 mm height 7 3 3 3 3 28 3 3 3 3 Water Permeability 100 mm dia. × 200 mm height 28 3 3 3 3 Sorptivity 100 × 200 cylinders were cut into 100 × 50mm disc 28 3 3 3 3 2.3 Experimental Setup 2.3.1 Compressive Strength Cylindrical specimens with a diameter of 100 mm and a height of 200 mm were tested by ASTM C39-21 [ 30 ] to evaluate the compressive strength of the OPC and LC 3 -50 concrete mixtures [ 31 ]. The compression testing machine with a 2000 kN load capacity and an accuracy of 1% is used for the compression testing of cylinders (refer to Fig. 3 ). The specimens were tested after 90, 180, 270, and 360 days of exposure to CO 2 in an accelerated environment. 2.3.2 Splitting Tensile Test ASTM C496/ C496M-11 [ 32 ] was followed while conducting the split tensile test. For split tensile strength testing, cylindrical samples with dimensions of 200 mm in height and 100 mm in diameter were cast. Concrete samples are removed from the mould and placed in the curing tank to cure for 28 days then placed in the carbonation chamber for accelerated 90, 180, 270, and 360 days (i.e. before being tested for split tensile strength. The test was conducted using a universal testing machine with a 500 kN limit (refer to Fig. 4). Figure 4: Setup for the determination of the split tensile test of concrete cylinders 2.3.4 Pull-out Test The basic concept behind pull-out testing is to determine how much force is required to remove a steel rod embedded in concrete. To assess the pull-out strength of hardened concrete, it measures the amount of force needed to remove an implanted rod. Three concrete cylinders measuring 100 mm in diameter and 200 mm in height were used, along with steel rods that had been embedded 100 mm into the specimen and had a rod length of 850 mm. UTM with a 500 kN capacity was used for the displacement control with a loading rate of 0.5 mm/min following ASTM C900 (refer to Fig. 5 ) [ 33 ]. 2.3.5 Carbonation The carbonation test is a pH test that reveals the pH depth, hence reducing the impact of carbonation on the concrete element. A carbonation test is used to determine the level of CO 2 infiltration in concrete. For this test, cylinder samples were placed inside an accelerated carbonation chamber and kept there for a specified duration of time. In the experiment, a 5% concentration of CO 2 was used for this test (refer to Fig. 6 ). The temperature was 23°C with a humidity level of 55%, as recommended by Dhir et al. [ 34 ]. It is acceptable to say that 11 hours of accelerated exposure to concrete in the carbonation chamber is equivalent to one month of natural exposure to the environment [ 34 ]. In an accelerated carbonation chamber, concrete samples from OPC and LC 3 -50 were exposed for 34, 68, 102, and 136 hours, respectively, simulating 3, 6, 9, and 12 months of natural exposure. The process of accelerated carbonation is highlighted as a positive approach for capturing CO 2 and a fascinating method to proactively reduce the alkalinity of the cement matrix. This is achieved by utilizing the Ca(OH) 2 ions present in the cement paste, leading to the densification of the matrix and a reduction in porosity. Additionally, the accelerated carbonation process was observed to involve the consumption of C-S-H (calcium silicate hydrate) and calcium sulfoaluminates (such as ettringite) [ 35 ]. 2.3.6 Water Permeability It is the property of a fluid to flow through interconnected pores. It is substantial in terms of durability because it causes reinforcement to corrode while allowing carbonation and other substances to penetrate the concrete. German Standard DIN 1048 [ 36 ] was used to determine it. Following a 28-day curing period, the equipment was assembled using three concrete cylinders measuring 100 mm in diameter and 200 mm in height. 500 kPa (5 bar) of water pressure was continually applied for 72 hours in the water permeability apparatus (refer to Fig. 7 ). To apply water pressure, a system with a water tank and an air compressor coupled by a valve to regulate pressure is used. The test outcome will be the average of the highest penetration levels attained from the three tested specimens. 2.3.7 Sorptivity Test In a uniform substance, the rate of absorption was assessed using water as the testing liquid, and the capillary absorption rate was measured. The procedure followed the guidelines outlined in ASTM C1585 [ 37 ]. Cylindrical specimens measuring 100 mm in diameter and 200 mm in height were made through casting and underwent a curing period of 28 days within a moist chamber. After they had cured, the specimens were cut into slices that were 50 mm thick (refer to Fig. 8 ), and the cylindrical surfaces of those pieces were then covered with epoxy. With a maximum height of 5 mm, these slices were placed just slightly above the specimen's base. A non-absorbent substance was used to properly seal the surface against liquid flow. Damp tissue was used to remove the extra surface moisture. The specimen was then weighed on a balance to determine the amount of water absorbed in 30 minutes. The amount of porosity was determined by multiplying the dry weight difference between the initial and final cylinder volumes after vacuum saturation. To standardize the data, which were obtained by plotting the rise in capillary mass over the square root of time, the pitch was adjusted to represent the total amount of water absorbed. This was divided by the thickness of the specimen determined by the sorption index [ 38 ]. 3. Result & Discussion 3.1 Effect of Carbonation 3.1.1 On the Compressive Strengths To better understand the impact of carbon dioxide (CO 2 ) exposure on the compressive strength of these specimens, controlled environments were maintained in carbonation, and their performance was monitored throughout 90, 180, 270, and 365 days. The specimens were cylindrical having a 100 mm diameter and height of 200 mm were tested for failure under the application of compressive load as per standard. In this section the comparison of compressive strength was discussed based on aggregate replacement, curing days, and binder type. 3.1.1.1 Comparison Based on Aggregate Replacement The average compression test result for the cylinder cast with OPC and LC3-50 after exposure to CO 2 is presented in Fig. 9 . For OPC concrete, compressive strength declined progressively with increased CO₂ exposure, irrespective of the aggregate type. A similar observation was reported by Ali et al. [ 39 ]. The normal weight aggregate (NWA) specimens initially achieved a peak strength of 55.4 MPa, while substituting lightweight aggregates (LWA) caused a 38% reduction. Post-exposure strength reductions for NWA specimens were 1.5%, 7.5%, 8.5%, and 14.3% after 90, 180, 270, and 365 days, respectively. In contrast, LWA specimens exhibited lower reductions of 1.3%, 2%, 3.5%, and 4.1%. The strength reduction of LWA specimens compared to NWA specimens after curing can be attributed to the lower mechanical properties of lightweight aggregates. However, under CO₂ exposure, LWA specimens demonstrated significantly improved performance. Carbonation leads to the formation of calcium carbonate from calcium hydroxide in the cement matrix, reducing alkalinity and disrupting the pore structure. The improved resistance to carbonation in lightweight concrete (LWC) was attributed to its denser pore structure, lower water-to-binder ratio, and higher cement content [ 20 ]. The enhanced performance of LWA specimens is linked to their physical characteristics, such as a denser microstructure, rough surface texture, and higher pH, which collectively limit CO₂ diffusion and reduce carbonation effects. Similarly, LC 3 -50 concrete exhibited a peak strength of 56.8 MPa with NWA, which decreased by 33% with LWA. Upon CO₂ exposure, NWA specimens showed strength losses of 8%, 9.2%, 14.1%, and 17.5% over the same durations, while LWA specimens demonstrated greater resistance, with reductions remaining below 4%. LC 3 -50 concrete specimens exhibited higher initial strength compared to OPC mixes, likely due to the synergistic pozzolanic reaction between calcined clay and limestone. This reaction generates additional C-S-H gel phases, improving the matrix's microstructural density and strength. For LWA specimens, reductions below 4% indicate that lightweight aggregates effectively mitigate carbonation effects. Additionally, the enhanced pH stability provided by LC 3 -50's cement chemistry complements the aggregates' properties, further reducing carbonation-induced deterioration. The enhanced performance of LWA specimens is linked to their physical characteristics, such as a denser microstructure, rough surface texture, and higher pH, which collectively limit CO₂ diffusion and reduce carbonation effects. Similarly, LC 3 -50 concrete exhibited a peak strength of 56.8 MPa with NWA, which decreased by 33% with LWA. Upon CO₂ exposure, NWA specimens showed strength losses of 8%, 9.2%, 14.1%, and 17.5% over the same durations, while LWA specimens demonstrated greater resistance, with reductions remaining below 4%. LC 3 -50 concrete specimens exhibited higher initial strength compared to OPC mixes, likely due to the synergistic pozzolanic reaction between calcined clay and limestone. This reaction generates additional C-S-H gel phases, improving the matrix's microstructural density and strength. For LWA specimens, reductions below 4% indicate that lightweight aggregates effectively mitigate carbonation effects. Additionally, the enhanced pH stability provided by LC 3 -50's cement chemistry complements the aggregates' properties, further reducing carbonation-induced deterioration. 3.1.1.2 Comparison Based on Binder Type For the case of compressive strengths exhibited after carbonation, specimens were prepared with 0% and 100% replacements of aggregates. The compressive strengths for OPC and LC 3 -50 specimens prepared with 0% aggregate replacement, it was found that OPC specimens exhibited higher compressive strength when natural aggregates were used as compared to LC 3 -50 specimens (refer to Fig. 10 ), whereas the specimens prepared with 100% lightweight aggregates, it was found that LC 3 -50 specimens exhibited higher compressive strengths as compared to OPC specimens. In all cases, it was observed that as exposure time increased, compressive strength decreased. This trend aligns with past literature; Mehmood et al. [ 40 ] also observed similar results when using recycled aggregates at different replacement levels. Comparing specimens LL-100 with LL-0, LL-100 exhibits a 10–11% greater compressive strength. In previous studies [ 41 , 42 ], it was observed that specimens exposed directly to carbonation experienced an increase in compressive strength. This phenomenon can be attributed to the formation of precipitates of calcium carbonate, rather than portlandite. However, when specimens were subjected to water curing initially, portlandite was formed. Subsequent exposure to carbonation led to a reduction in portlandite content, thereby decreasing alkalinity levels. In conditions of low alkalinity, the stability of the CSH gel was compromised, consequently resulting in a decrease in strength [ 43 ]. 3.1.2 On the Splitting Tensile Strengths To study the splitting tensile behavior of specimens cast with OPC and LC 3 -50 concrete after carbon dioxide (CO 2 ) exposure the specimens were placed in the carbonation chamber for 90, 180, 270, and 365 days. In this section, the comparison of compressive strength was carried out based on aggregate replacement, curing days, and binder type. 3.1.2.1 Comparison Based on Aggregate Replacement The average tensile test results for cylinders cast with OPC and LC 3 -50 after exposure to CO 2 are presented in Fig. 11 . By observing the result, it was found that the tensile strength decreases as the exposure time increases irrespective of the aggregate type. In their study on recycled aggregate, Mehmood et al. [ 40 ] observed a similar trend in their results. For OPC concrete, the tensile strength decreased with increasing exposure time, regardless of the aggregate type. Specimens cast with 100% natural aggregates initially exhibited good strength, reaching 4.33 MPa. However, using only lightweight aggregates resulted in a 31% reduction in maximum strength. After exposure to CO 2 for 90, 180, 270, and 365 days, specimens made with natural aggregates showed a continuous decline in tensile strength, with reductions of 4%, 8.3%, 8.7%, and 14.6%, respectively, compared to the control specimens. In contrast, specimens made with 100% lightweight aggregates demonstrated a more resilient response, with much smaller decreases in tensile strength (0.1%, 1.1%, 2.9%, and 5.8% for the same exposure times). Throughout all exposure times, specimens made with natural aggregates consistently showed higher strength than those made with lightweight aggregates, with variations in strength ranging from 23–28%. For LC 3 -50 concrete, after a 28-day curing period, specimens cast with natural aggregates reached a peak strength of 4.59 MPa, whereas those made with lightweight aggregates showed a significant 27% loss in strength. Upon CO 2 exposure, a decreasing trend in strength was observed for specimens cast with natural aggregates, with reductions of 4.9%, 8.5%, and 11.5% after 90, 180, and 365 days, respectively. Conversely, specimens made with 100% lightweight aggregates showed an unusual pattern, with tensile strength increasing by 15–20% over the same exposure periods. This indicates that lightweight concrete exhibited improved resilience to CO 2 exposure compared to normal weight concrete (NWC). The interaction between the LC 3 -50 matrix and the lightweight aggregates explains this oddness. Because of their porous nature, lightweight aggregates may offer more pozzolanic reactions, perhaps improving the concrete's overall microstructure and resistance to CO 2 exposure. This phenomenon may possibly be linked to the LC 3 -50 mix's greater calcium silicate and aluminum phase concentrations, which could improve lightweight aggregates' pozzolanic activity and account for the strength enhancement that has been seen. Additionally, the tensile strength improvement is consistent with earlier research showing that LWC often has lower carbonation levels than NWC. This anomaly can be explained by the interaction between the lightweight aggregates and the LC 3 -50 matrix. Lightweight aggregates may provide additional pozzolanic reactions due to their porous nature, possibly enhancing the overall microstructure and resilience of the concrete under CO 2 exposure. This phenomenon could also be related to the higher levels of calcium silicate and aluminum phases within the LC 3 -50 mix, which may enhance the pozzolanic activity of lightweight aggregates and contribute to the observed strength gain. Lightweight concrete (LWC) of similar strength grade to normal weight concrete (NWC) exhibited lower carbonation levels compared to NWC mixes [ 20 ]. 3.1.2.2 Comparison Based on Binder Type The tensile strengths exhibited after carbonation, specimens prepared with 0% and 100% replacement were considered similar to the case of compressive tests. When comparing the tensile strengths for OPC and LC 3 -50 specimens, it was observed that LC 3 -50 specimens outperformed OPC specimens, irrespective of the percentage of replacement used (refer to Fig. 12 ). In the case of OPC, the reduction of tensile strength after carbonation is 28%, whereas the reduction in LC 3 -50 is 7%, which is considerable. The performance of LC 3 -50 concrete specimens compared to OPC counterparts while using only 100% natural weight aggregates was noticeably improved by 5–9%. From the observations made above, it can be concluded that the influence of lightweight aggregates is more dominant in LC 3 -50 for tensile strength as compared to compressive strengths. For all the cases, it was also found that as the exposure time increases, tensile strength decreases. 3.2 Pull-Out Strength Figure 13 shows the results of pullout tests conducted on specimens at 7 and 28 days of curing. In general, it was observed that specimens exhibit higher pull-out strength at 28 days of curing as compared to that observed at 7 days of curing. When tested at 28 days, it was observed that specimens prepared with LC 3 -50 exhibited higher pull-out strength as compared to OPC when natural aggregates were used. Earlier studies have indicated that LC 3 -50 concrete possesses a denser microstructure characterized by reduced porosity and an improved ratio of splitting to compressive strength when compared to OPC concrete. Additionally, LC 3 -50 concrete exhibits a higher elastic modulus and greater bond stress between the concrete and steel bar. Notably, LC 3 -50 concrete demonstrates a higher bond-slip stiffness in comparison to OPC concrete. [ 16 ]. When comparing the effect of the inclusion of lightweight aggregates on pull-out strength, it was observed that both OPC and LC 3 -50 specimens exhibit almost similar behavior. 3.3 Water Permeability The permeability tests were conducted for OPC and LC 3 -50 specimens prepared with 0% and 100% replacement. When comparing the type of cement composition, it was observed that OPC specimens exhibit higher permeability approximately 70% higher as compared to LC 3 -50 specimens (refer to Fig. 14 ). This may be due to the presence of voids in the concrete matrix which provides permeability. An Indian pore structure study suggests that the LC 3 -50 system had a higher resistivity. Its paste phase may have a higher ionic transport barrier. Hence, it has lower inherent permeability [ 44 ]. The results indicate that the utilization of the LC 3 -50 blend is viable for various applications involving water exposure or underwater placement of concrete. In such scenarios, the need for additional water protection measures, like crystalline waterproofing, can be reduced compared to OPC cement. Consequently, this reduction in the usage of supplementary materials leads to increased cost-effectiveness for the project. When comparing the effect of using lightweight aggregates, it was observed that for 100% replacement of natural aggregates with lightweight aggregates, permeability is decreased significantly by about 50%, irrespective of the type of concrete used. 3.4 Sorptivity Figure 15 gives the absorption capacity of normal-weight and lightweight specimens prepared with LC 3 -50 and OPC. It was observed that specimens prepared with OPC exhibited higher sorptivity, irrespective of the type of aggregates used. When comparing the effect of using different types of cement, it was observed that lightweight concrete prepared with OPC exhibits a 21% higher rate of absorption as compared to LC 3 -50 specimens. According to an Indian study, the adsorption rate is lowered by the pozzolanic and filler impact brought on by SCM addition and more sinuous pores in LC 3 -50 mixtures of concrete and due to contraction in pore diameters at an initial point of the concrete that affects in immediate augmentation of durability performance for concrete [ 23 ]. 4. Conclusion Based on the comprehensive experimental research on the usage of lightweight aggregate replacements for LC 3 -50 and concrete and comparisons with OPC and LC 3 -50 based concretes, the following are the conclusions drawn: Compressive strength and splitting tensile strength of concrete decreased with longer CO 2 exposure, irrespective of aggregate type. Over the same exposure periods, concrete containing lightweight aggregates responded to CO 2 exposure more favorably, showing lower reductions in compressive strength (ranging from 1.3–4.1%) and relatively slight declines in tensile strength (ranging from 0.1–5.8%). In comparison to LC 3 -50 specimens using natural aggregates, OPC specimens exhibited higher compressive strengths. Conversely, LC 3 -50 specimens incorporating 100% lightweight aggregates showed higher strengths than OPC counterparts, with all cases experiencing a decrease in strength with an increase in CO 2 exposure time. Additionally, 100% lightweight aggregates resulted in 10–11% higher strength in comparison to 0% lightweight aggregates. In terms of tensile behavior, LC 3 -50 concrete consistently demonstrated higher tensile strength than OPC regardless of replacement percentages. Furthermore, after carbonation, LC 3 -50 showed a far lesser reduction in tensile strength than OPC—a decline of 7% in LC 3 -50 against 28% in OPC. Compared to their OPC counterparts, LC 3 -50 specimens with 100% natural aggregates showed an improvement of 5–9%. It's interesting to note that lightweight aggregates had a greater impact on LC 3 -50's tensile strength than on its compressive strength. Longer exposure times consistently resulted in a drop in tensile strength. In terms of water resistance and pull-out strength, LC 3 -50 concrete outperforms OPC concrete. LC 3 -50's denser structure and improved bonding contribute to its higher pull-out strength and lower permeability. Lightweight aggregates also reduce permeability significantly in both types of concrete. Although OPC has higher sorptivity, LC 3 -50's advantages make it a promising choice for stronger and more durable construction, especially when combined with lightweight aggregates. Declarations Author Contribution Syed Fahad Hussain carried out the experimental investigation and drafted the manuscript under the guidance of Prof Dr Tehmina Ayub. Dr Tariq Jamil was the Principal Investigator who secured financial support from the Higher Education Commission of Pakistan, National Research Program for Universities (NRPU) Project no. 14074 entitled “Development of Cost-Effective Structural Concrete Formulation using Limestone Calcined Clay Based LC3 Cement Blend with Domestic Resources and its Application in a Pilot Project.” The authors are grateful for the valuable input from Prof. Dr. Karen Scrivener, Head of the Laboratory of Construction Materials, Swiss Federal Institute of Technology (EPFL) based in Lausanne, Switzerland. Acknowledgement The authors are grateful and acknowledge the support from the Higher Education Commission of Pakistan, National Research Program for Universities (NRPU) Project no. 14074 entitled “Development of Cost-Effective Structural Concrete Formulation using Limestone Calcined Clay Based LC3 Cement Blend with Domestic Resources and its Application in a Pilot Project.” The authors are grateful for the valuable input from Prof. Dr. Karen Scrivener, Head of the Laboratory of Construction Materials, Swiss Federal Institute of Technology (EPFL) based in Lausanne, Switzerland. References Mahmood, W., A.-u.-R. Khan, and T. Ayub, Mechanical and durability properties of concrete containing recycled concrete aggregates. Iranian Journal of Science and Technology, Transactions of Civil Engineering, 2021: p. 1-20. Environment, U., et al., Eco-efficient cements: Potential economically viable solutions for a low-CO2 cement-based materials industry. Cement and concrete Research, 2018. 114 : p. 2-26. Ayub, A., et al., Mechanical and Durability Properties of High-Strength Limestone Calcined Clay Cement (LC3) Concrete Containing Waste Glass Powder. Iranian Journal of Science and Technology, Transactions of Civil Engineering, 2023: p. 1-20. Imbabi, M.S., C. Carrigan, and S. McKenna, Trends and developments in green cement and concrete technology. International Journal of Sustainable Built Environment, 2012. 1 (2): p. 194-216. Alexander, M., A. Bentur, and S. Mindess, Durability of concrete: design and construction . Vol. 20. 2017: CRC Press. Hussain, S.M.F., et al., Initial search for low grade clay in Pakistan for producing LC3 ecofriendly cement. Low-carbon Materials and Green Construction, 2023. 1 (1): p. 15. Davidovits, J., Global warming impact on the cement and aggregates industries. World resource review, 1994. 6 (2): p. 263-278. Scrivener, K., Eco-efficient cements: No magic bullet needed. Glob. Cem. Mag, 2019: p. 10-14. Marangu, J.M., Physico-chemical properties of Kenyan made calcined Clay-Limestone cement (LC3). Case Studies in Construction Materials, 2020. 12 : p. e00333. Muleya, F., et al., PARTIAL REPLACEMENT OF CEMENT WITH RICE HUSK ASH IN CONCRETE PRODUCTION: AN EXPLORATORY COST-BENEFIT ANALYSIS FOR LOW-INCOME COMMUNITIES. Engineering Management in Production & Services, 2021. 13 (3). Akan, M.Ö.A., D.G. Dhavale, and J. Sarkis, Greenhouse gas emissions in the construction industry: An analysis and evaluation of a concrete supply chain. Journal of Cleaner Production, 2017. 167 : p. 1195-1207. Scrivener, K., et al., Calcined clay limestone cements (LC3). Cement and Concrete Research, 2018. 114 : p. 49-56. Sheikh, M.D., et al., Comparative Study on LC 3-50 with OPC Concrete Using Raw Materials from Pakistan. Advances in Materials Science and Engineering, 2023. 2023 . Scrivener, K., et al., Impacting factors and properties of limestone calcined clay cements (LC3). Green Materials, 2018. 7 (1): p. 3-14. Li, R. and H. Ye, Influence of alkalis on natural carbonation of limestone calcined clay cement pastes. Sustainability, 2021. 13 (22): p. 12833. Huang, Z.-y., et al., Development of limestone calcined clay cement concrete in South China and its bond behavior with steel reinforcement. Journal of Zhejiang University-SCIENCE A, 2020. 21 (11): p. 892-907. Lu, J.-X., et al., Development of high performance lightweight concrete using ultra high performance cementitious composite and different lightweight aggregates. Cement and Concrete Composites, 2021. 124 : p. 104277. Malik, M., S. Bhattacharyya, and S.V. Barai, Thermal and mechanical properties of concrete and its constituents at elevated temperatures: A review. Construction and Building Materials, 2021. 270 : p. 121398. Alexander, M. and S. Mindess, Aggregates in concrete . 2005: CRC Press. Lo, T., W. Tang, and A. Nadeem, Comparison of carbonation of lightweight concrete with normal weight concrete at similar strength levels. Construction and Building Materials, 2008. 22 (8): p. 1648-1655. Teo, D., et al., Lightweight concrete made from oil palm shell (OPS): Structural bond and durability properties. Building and environment, 2007. 42 (7): p. 2614-2621. Alujas, A., et al., Pozzolanic reactivity of low grade kaolinitic clays: Influence of calcination temperature and impact of calcination products on OPC hydration. Applied Clay Science, 2015. 108 : p. 94-101. Dhandapani, Y., et al., Mechanical properties and durability performance of concretes with Limestone Calcined Clay Cement (LC3). Cement and Concrete Research, 2018. 107 : p. 136-151. Sree, S.K., et al. Experimental studies on mechanical and durability characteristics of lc3 concrete . in IOP Conference Series: Materials Science and Engineering . 2021. IOP Publishing. Javadi, A., et al., Working mechanisms and design principles of comb-like polycarboxylate ether superplasticizers in cement hydration: quantitative insights for a series of well-defined copolymers. ACS Sustainable Chemistry & Engineering, 2021. 9 (25): p. 8354-8371. Astm, A., Standard test method for relative density (specific gravity) and absorption of coarse aggregate. ASTM West Conshohocken, PA, 2015. Standard, B., BS 812-110: 1990 Testing Aggregates-Part 110: Methods for Determination of Aggregate Crushing Value (ACV). Bsi, Uk, 1990. Aashto, T., Standard method of test for resistance to degradation of small-size coarse aggregate by abrasion and impact in the Los Angeles machine. American Association of State Highway and Transportation Officials, 2002. , A.C., Report on High-Strength Concrete (ACI 363R-10) . 2010: ACI. C39/C39M-21, A., Standard Test Method for Compressive Strength of Cylindrical Concrete Specimens . 2021, American Standard Test Method: West Conshohocken, Penn, USA. Concrete, A.I.C.C.o. and C. Aggregates, Standard test method for compressive strength of cylindrical concrete specimens . 2014: ASTM international. Standard, A., C496/c496m (2011) Standard Test Method for Splitting Tensile Strength of Cylindrical Concrete Specimens. Annual Book of ASTM Standards, 2004. 9 . Richards, O., Pullout strength of concrete . 1977: ASTM International. Dhir, R., P. Hewlett, and Y. Chan, Near-surface characteristics of concrete: prediction of carbonation resistance. Magazine of Concrete Research, 1989. 41 (148): p. 137-143. Pizzol, V.D., et al., Effect of accelerated carbonation on the microstructure and physical properties of hybrid fiber-cement composites. Minerals Engineering, 2014. 59 : p. 101-106. Standard, G., DIN 1048––test methods of concrete impermeability to water: Part 2. Deutscher Institute Fur Normung, Germany, 1978. Astm, C., 1585-04. Standard test method for measurement of rate of absorption of water by hydraulic-cement concretes. ASTM International, 2004. Bu, Y., R. Spragg, and W. Weiss, Comparison of the pore volume in concrete as determined using ASTM C642 and vacuum saturation. Advances in Civil Engineering Materials, 2014. 3 (1): p. 308-315. Ali, M., M.S. Abdullah, and S.A. Saad, Effect of calcium carbonate replacement on workability and mechanical strength of Portland cement concrete. Advanced materials research, 2015. 1115 : p. 137-141. Mahmood, W., A.-u.-R. Khan, and T. Ayub, Carbonation resistance in ordinary Portland cement concrete with and without recycled coarse aggregate in natural and simulated environment. Sustainability, 2021. 14 (1): p. 437. Merah, A. and B. Krobba, Effect of the carbonatation and the type of cement (CEM I, CEM II) on the ductility and the compressive strength of concrete. Construction and Building Materials, 2017. 148 : p. 874-886. Kim, J.-K., et al., Effect of carbonation on the rebound number and compressive strength of concrete. Cement and Concrete Composites, 2009. 31 (2): p. 139-144. Zajac, M., et al., CO2 mineralization methods in cement and concrete industry. Energies, 2022. 15 (10): p. 3597. Dhandapani, Y. and M. Santhanam, Assessment of pore structure evolution in the limestone calcined clay cementitious system and its implications for performance. Cement and Concrete Composites, 2017. 84 : p. 36-47. Additional Declarations No competing interests reported. Cite Share Download PDF Status: Published Journal Publication published 12 Mar, 2025 Read the published version in Iranian Journal of Science and Technology, Transactions of Civil Engineering → Version 1 posted Editorial decision: Revision requested 14 Jan, 2025 Reviews received at journal 14 Jan, 2025 Reviews received at journal 27 Dec, 2024 Reviews received at journal 26 Dec, 2024 Reviews received at journal 24 Dec, 2024 Reviews received at journal 24 Dec, 2024 Reviews received at journal 22 Dec, 2024 Reviewers agreed at journal 21 Dec, 2024 Reviewers agreed at journal 21 Dec, 2024 Reviewers agreed at journal 20 Dec, 2024 Reviews received at journal 20 Dec, 2024 Reviewers agreed at journal 20 Dec, 2024 Reviews received at journal 19 Dec, 2024 Reviewers agreed at journal 19 Dec, 2024 Reviewers agreed at journal 19 Dec, 2024 Reviewers agreed at journal 19 Dec, 2024 Reviewers agreed at journal 19 Dec, 2024 Reviewers agreed at journal 19 Dec, 2024 Reviewers agreed at journal 19 Dec, 2024 Reviewers agreed at journal 19 Dec, 2024 Reviewers invited by journal 19 Dec, 2024 Editor assigned by journal 17 Dec, 2024 Submission checks completed at journal 17 Dec, 2024 First submitted to journal 17 Dec, 2024 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-5658989","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":391723785,"identity":"56cf3378-e08b-4753-89b8-f283c863f37c","order_by":0,"name":"Syed Muhammad Fahad Hussain","email":"","orcid":"","institution":"DHA Suffa University","correspondingAuthor":false,"prefix":"","firstName":"Syed","middleName":"Muhammad Fahad","lastName":"Hussain","suffix":""},{"id":391723786,"identity":"46b76ee1-ba44-4143-9ff1-439c03c13868","order_by":1,"name":"Tehmina 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15:56:56","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":68377,"visible":true,"origin":"","legend":"\u003cp\u003eSetup for the determination of the compression test of concrete cylinders\u003c/p\u003e","description":"","filename":"floatimage3.png","url":"https://assets-eu.researchsquare.com/files/rs-5658989/v1/48f2d570399875f6441fb777.png"},{"id":71912423,"identity":"5e7456f9-709f-4849-959a-0e932727d656","added_by":"auto","created_at":"2024-12-19 16:04:56","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":100984,"visible":true,"origin":"","legend":"\u003cp\u003eSetup for the determination of the split tensile test of concrete 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concrete\u003c/p\u003e","description":"","filename":"floatimage6.png","url":"https://assets-eu.researchsquare.com/files/rs-5658989/v1/2919f542910950b86f9cef4e.png"},{"id":71911957,"identity":"19fee3ed-fdba-4c44-b436-99be442f6860","added_by":"auto","created_at":"2024-12-19 15:56:56","extension":"png","order_by":7,"title":"Figure 7","display":"","copyAsset":false,"role":"figure","size":135352,"visible":true,"origin":"","legend":"\u003cp\u003eSetup for the determination of the permeability test of concrete\u003c/p\u003e","description":"","filename":"floatimage7.png","url":"https://assets-eu.researchsquare.com/files/rs-5658989/v1/95606620468b1c9464f5dedd.png"},{"id":71911940,"identity":"dd1b8e39-008c-4416-87fb-5c4946b15c6f","added_by":"auto","created_at":"2024-12-19 15:56:56","extension":"png","order_by":8,"title":"Figure 8","display":"","copyAsset":false,"role":"figure","size":89505,"visible":true,"origin":"","legend":"\u003cp\u003eSetup for the determination of the Sorptivity test of 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13","display":"","copyAsset":false,"role":"figure","size":23843,"visible":true,"origin":"","legend":"\u003cp\u003ePullout capacity of lightweight specimens prepared with LC3-50 and OPC\u003c/p\u003e","description":"","filename":"floatimage13.png","url":"https://assets-eu.researchsquare.com/files/rs-5658989/v1/cc6b9d8905e5befa0253a9e1.png"},{"id":71911977,"identity":"50016e2a-8d5c-4e3c-bcb6-684c0ece7f8d","added_by":"auto","created_at":"2024-12-19 15:56:58","extension":"png","order_by":14,"title":"Figure 14","display":"","copyAsset":false,"role":"figure","size":49545,"visible":true,"origin":"","legend":"\u003cp\u003ePermeability of lightweight specimens prepared with LC\u003csup\u003e3\u003c/sup\u003e-50 and OPC\u003c/p\u003e","description":"","filename":"floatimage14.png","url":"https://assets-eu.researchsquare.com/files/rs-5658989/v1/debc2fc9cc0213593acb8568.png"},{"id":71912426,"identity":"4ddb8aa5-4a9c-4e90-8b99-ec8a54f80afc","added_by":"auto","created_at":"2024-12-19 16:04:56","extension":"png","order_by":15,"title":"Figure 15","display":"","copyAsset":false,"role":"figure","size":58574,"visible":true,"origin":"","legend":"\u003cp\u003eAbsorption capacity of lightweight specimens prepared with LC\u003csup\u003e3\u003c/sup\u003e-50 and OPC\u003c/p\u003e","description":"","filename":"floatimage15.png","url":"https://assets-eu.researchsquare.com/files/rs-5658989/v1/a4caea91a53d23b0ac5d5f0f.png"},{"id":78689376,"identity":"5f81efcf-ff6c-4772-b820-97ea7cfd10bf","added_by":"auto","created_at":"2025-03-17 16:12:35","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":2481657,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-5658989/v1/3141389a-1172-4b87-b6cd-ad8f32cf055d.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"\u003cp\u003eDurability Performance of Opc and Lc 3 -50 Concrete Containing Lightweight Aggregates\u003c/p\u003e","fulltext":[{"header":"1. Introduction","content":"\u003cp\u003eIn recent years, there has been a growing interest in developing innovative construction materials that reduce the environmental impact of construction activities and exhibit enhanced performance characteristics. Green concrete is being used to produce sustainable infrastructure, which has caught the attention of stakeholders in construction and structural design. The population of the globe has expanded due to the global economic crisis, which has led to an increase in construction waste production and the development of innovative, energy-efficient building techniques for sustainable structures, among other things [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e]. All around the world, cement is used as the main building material for constructing buildings and other infrastructure [\u003cspan additionalcitationids=\"CR3\" citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e]. The expanding demand in the building industry has resulted in a significant growth in cement consumption globally over time. Over 10\u0026nbsp;billion cubic meters of concrete are produced annually worldwide, and this number is not anticipated to decline [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e, \u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e]. There is significant carbon dioxide (CO\u003csub\u003e2\u003c/sub\u003e) emissions into the atmosphere throughout the OPC production process. The cement industry is thought to be responsible for between 5 and 8% of the world's CO\u003csub\u003e2\u003c/sub\u003e emissions caused by human activity [\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e]. It is projected that worldwide CO\u003csub\u003e2\u003c/sub\u003e emissions will surpass those of pre-industrial levels by 2028, leading to an increase in global warming of over 1.5\u003csup\u003eo\u003c/sup\u003eC [\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eThe clinkerization and grinding stages of the OPC manufacturing process are the most expensive since they require a large amount of fuel energy [\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e]. Consequently, numerous consumers in underdeveloped nations cannot afford Portland cement [\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e]. Globally, the primary focus is on achieving the targets for sustainable growth and reducing the carbon footprint associated with the cement manufacturing process. Reducing the amount of clinker in cement is becoming increasingly important in the construction industry [\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e]. For this reason, replacing suitable materials like limestone and calcined clay for the clinker in Portland cement can help reduce its amount. In the process of making cement, this lowers CO\u003csub\u003e2\u003c/sub\u003e emissions and total production costs [\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e]. A new type of blended cement made of limestone and calcined clay, known as limestone calcined clay cement (LC\u003csup\u003e3\u003c/sup\u003e-50), has 50% less clinker. Compared to ordinary cement, the CO\u003csub\u003e2\u003c/sub\u003e emissions are reduced to 30% with this 50% clinker reduction in LC\u003csup\u003e3\u003c/sup\u003e-50 [\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e]. Furthermore, it has been observed that practical concretes employing LC\u003csup\u003e3\u003c/sup\u003e-50 can be produced without requiring substantial modifications to the conventional method of mixture design, even in the face of the highly variable structures of the clay particles. Along with many other benefits, LC\u003csup\u003e3\u003c/sup\u003e-50 outperforms OPC in terms of durability. Alkali-silica reaction (ASR), steel corrosion, sulfate assault, and chloride intrusion are all prevented by it. Previous studies explore the durability aspects of Limestone Calcined Clay Cement (LC\u003csup\u003e3\u003c/sup\u003e-50) and its properties. Scrivener et al. [\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e] investigate the carbonation rate of LC\u003csup\u003e3\u003c/sup\u003e-50 and OPC mortars after 3 and 28-day curing periods, noting the significance of calcium oxide (CaO) in regulating carbonation. Thorough curing enhances carbonation resistance, influenced by environmental humidity levels. Li and Ye [\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e] analyzed LC\u003csup\u003e3\u003c/sup\u003e-50 paste's carbonation resistance, finding it lower than OPC paste, with carbonation depth ranging from 2.4 to 4.5 mm in 23 weeks. Huang et al. [\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e] studied bond behavior between LC\u003csup\u003e3\u003c/sup\u003e-50 concrete and steel rebar, showing a linear increase in bond strength with compressive strength and the impact of rebar diameter on bond stress.\u003c/p\u003e \u003cp\u003eAs the construction sector seeks innovative materials to reduce its environmental footprint and enhance performance one material that is receiving a lot of attention is lightweight concrete, which is made of shale as a lightweight aggregate. Shale, a sedimentary rock that forms when fine-grained mineral and organic particles are compacted, has shown great potential as a building material, especially when it comes to lightweight concrete. In the search for high-performance and environmentally friendly building materials, shale presents a strong alternative to conventional aggregates because of its unique physical and chemical characteristics and wide availability [\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e]. Shale is made up of thinly arranged particles that have a relatively low density and maintain structural integrity. This property works well to develop building materials that are both strong and lightweight [\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e]. Its composition often includes minerals like clay, quartz, and various silicates, contributing to its potential as a suitable aggregate in concrete mixtures [\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e]. Furthermore, the availability of shale in a variety of geological formations across several countries offers a sustainable substitute for conventional aggregate sources, reducing concerns about resource depletion and emissions from transportation.\u003c/p\u003e \u003cp\u003eUsing lightweight aggregates, scarce studies are reported in the literature. The study reported by Lo et al. [\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e] compares the carbonation effects between lightweight concrete (LWC) and normal-weight concrete (NWC) with similar strength levels. Various binders and aggregates were used to investigate concrete behavior. The carbonation depth was measured after exposing concrete cubes to CO\u003csub\u003e2\u003c/sub\u003e gas under different curing conditions. Results indicate that carbonation depth increases with a higher water-to-binder (w/b) ratio and lower binder content. LWC generally exhibited lower carbonation compared to NWC, attributed partly to NWC's lower cement concentration. The investigation by Teo et al. [\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e] focused on the structural bond and durability properties of lightweight concrete using oil palm shells as a lightweight aggregate. The bond strength test on reinforcing bars with varying diameters was conducted under different curing conditions. Bond strength varied based on curing conditions and bar size, with deformed bars in full water curing providing the highest bond strength. Larger bar sizes led to reduced bond strength due to decreased confining pressure from the surrounding concrete. Under carbonation effects, the compressive and split tensile strengths of lightweight concrete using OPC and LC\u003csup\u003e3\u003c/sup\u003e as binders have not yet been investigated. This study addresses this gap by evaluating the durability of lightweight aggregate concrete prepared with Ordinary Portland Cement (OPC) and LC\u003csup\u003e3\u003c/sup\u003e-50. Two replacements for lightweight aggregate (0% and 100%) were investigated. The durability evaluation included the effect of carbonation on compressive strength and split tensile strength, pull-out strength, water permeability, and sorptivity.\u003c/p\u003e"},{"header":"2. Material \u0026 Methods","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003e2.1 Raw Materials\u003c/h2\u003e \u003cp\u003eIn this study, 53-grade Ordinary Portland Cement (OPC) and Limestone Calcined Clay Cement (LC\u003csup\u003e3\u003c/sup\u003e-50) were used. LC\u003csup\u003e3\u003c/sup\u003e-50 was produced by combining materials in specific proportions: 50% clinker, 30% clay, 15% limestone, and 5% gypsum, all measured by mass. First, the clay was calcined at about 800\u0026ordm;C. It was then mixed with clinker that had been calcined at around 1500\u0026ordm;C. This procedure required the use of clay that was enhanced with a significant amount of kaolin minerals more than 40%. To determine the kaolinite concentration of clay, thermogravimetric (TG) analysis was performed. Based on the mass loss (\u0026#119898;\u003csub\u003e\u0026#119897;\u0026#119900;\u0026#119904;\u0026#119904;\u003c/sub\u003e) between 400 and 600\u003csup\u003eo\u003c/sup\u003eC using the TG tangent method, the kaolinite content was calculated [\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eFor this study, calcined clay was provided by an industrial facility at Nagarparkar, Tharparkar, Sindh. In an electric furnace, the clay was calcined at 800\u0026deg;C for over an hour. As a result, after being calcined at 800\u0026deg;C, the clay becomes reactive [\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e]. The chemical composition of calcined clay, OPC, Limestone, and LC\u003csup\u003e3\u003c/sup\u003e-50 is mentioned in Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e. The gypsum within this setup was fine-tuned to promote the progression of the aluminates' reaction (derived from calcined clay) beyond the primary calcium silicate reaction, as observed in isothermal calorimetry [\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e]. The particle size distribution of OPC, calcined clay, limestone, and LC\u003csup\u003e3\u003c/sup\u003e-50 by laser diffraction is given in Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e. The project utilizes locally sourced coarse and fine aggregates. To prevent voids in the concrete, a mix design incorporating a combination of 10 mm and 16 mm coarse aggregates was employed. The fine aggregate was sieved using a 4.75 mm mesh. The reactivity of the pozzolana increases, leading to a need for more water to generate a secondary gel phase [\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e]. For enhancing concrete performance in terms of workability and early strength, ViscoCrete-3110, a third-generation superplasticizer is used [\u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e]. The appropriate dosage of the superplasticizer is crucial to achieve the desired hydration content in the concrete due to the fine nature of the calcined clay, which necessitates additional water. The shale was used as a lightweight aggregate (refer to Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e). The raw shale is extracted from the local site of Baluchistan located near Lasbela. The raw shale was bloated at 1000\u003csup\u003eo\u003c/sup\u003eC through an electric furnace. The chemical composition is also given in Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e.\u003c/p\u003e \u003cp\u003eThe physical characteristics of shale were assessed through physical testing of the aggregates, and Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e provides details on the aggregate's physical properties. Specific gravity and water absorption of lightweight aggregates were determined following ASTM C127-15 [\u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e] guidelines, while the crushing value and impact value were determined according to BS 812\u0026thinsp;\u0026minus;\u0026thinsp;110 [\u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e] and ASTM C131-20 [\u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e] standards, respectively. The crushing value and water absorption percentage of lightweight aggregates deviate from the recommended limits, likely attributable to the porous nature of shale. Conversely, the values for impact strength and specific gravity are within the specified range.\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\u003eChemical composition of ordinary Portland cement (OPC), Calcined Clay, Limestone, LC\u003csup\u003e3\u003c/sup\u003e-50, and Shale\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"6\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" 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 \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003eOxides\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"5\" nameend=\"c6\" namest=\"c2\"\u003e \u003cp\u003eOxides Content (%)\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eOrdinary Portland Cement (OPC)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eCalcined Clay\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eLimestone\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003eLimestone Calcined Clay (LC\u003csup\u003e3\u003c/sup\u003e-50)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c6\"\u003e \u003cp\u003eShale\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCaO\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e61.17\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e2.29\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e54.6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e34.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e4.03\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSiO2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e18.47\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e41.61\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.02\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e22\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e70.1\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAl2O3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e4.28\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e33.8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.04\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e12\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e8.83\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eFe2O3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e4.77\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e0.48\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.05\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e1.72\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e4.49\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eMgO\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e1.51\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e0.35\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.15\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.93\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e0.74\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eNa2O\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e0.1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e0.1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.01\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.13\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e0.19\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eK2O\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e0.54\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e0.06\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\u003e0.4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e1.65\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSO3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e2.6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e0.01\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.03\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e3.12\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e0.05\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eOthers\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e6.56\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e21.3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e45.1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e25.2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e9.92\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 \u003cp\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 properties of lightweight aggregate\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"5\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePhysical Properties\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eCrushing Value\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eSpecific Gravity\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eAbsorption\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003eImpact Value\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTest Results\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e53%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2.3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e9%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e49%\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eStandard Range (%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u0026lt;\u0026thinsp;30 [\u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e]\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2.4-3 [\u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e]\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.1-2 [\u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e]\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e\u0026lt;\u0026thinsp;45 [\u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e]\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=\"Sec4\" class=\"Section2\"\u003e \u003ch2\u003e2.2 Mix Design\u003c/h2\u003e \u003cp\u003eThe design mix was trialed to achieve a target strength of 55.5 MPa (8000 psi) at 28 days, following the guidelines of ACI Committee 363\u0026thinsp;\u0026minus;\u0026thinsp;10 [\u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e]. The ratio of cement to water was maintained at 0.32 during the casting procedure. The remaining volume was divided into a 60:40 ratio of fine and coarse aggregates using a volumetric mix design. In addition, a 30:70 blend of coarse aggregates made of 10 mm and 16 mm aggregates was used. A superplasticizer (SP) was added to the concrete at a dosage of 1.6% in proportion to the cement quantity to improve workability and achieve the requisite 180 mm slump. The durability properties of both OPC and LC\u003csup\u003e3\u003c/sup\u003e-50 concrete were tested using the mix design shown in Table\u0026nbsp;\u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e3\u003c/span\u003e. The raw materials were carefully mixed in a pan mixer operating at 25 revolutions per minute. Ordinary Portland Cement (OPC) is denoted by the letter \"O\" in the \"OL\" concrete mix, while \"Lightweight aggregates\" is denoted by the letter \"L\" in Table\u0026nbsp;\u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e3\u003c/span\u003e's nomenclature. Similarly, in the \"LL\" concrete mix, \"L\" represents the LC\u003csup\u003e3\u003c/sup\u003e-50 blend, and \"L\" still refers to \"Lightweight aggregates\". The percentage of light-weight aggregate used for replacement is indicated by the number following the hyphen.\u003c/p\u003e \u003cp\u003eThe dimensions of the test samples and the duration of their curing and exposure is presented in Table\u0026nbsp;\u003cspan refid=\"Tab4\" class=\"InternalRef\"\u003e4\u003c/span\u003e. All the specimens investigated in this research were cast using two different types of binders: Ordinary Portland Cement (OPC) and LC\u003csup\u003e3\u003c/sup\u003e-50.\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 design of OPC and LC\u003csup\u003e3\u003c/sup\u003e-50 concrete\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"5\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003eMaterials\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"4\" nameend=\"c5\" namest=\"c2\"\u003e \u003cp\u003eMix ID\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eOL-00\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eOL-100\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eLL-0\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003eLL-100\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eOPC\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e728\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e728\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eLC\u003csup\u003e3\u003c/sup\u003e-50\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e728\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e728\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSilica Fumes\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e51\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e51\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e51\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e51\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eWater- Binder Ratio\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0.32\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.32\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.32\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.32\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eNatural Aggregates\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e815\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e815\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eLightweight Aggregates (Shale)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e815\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e815\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eFine Aggregates\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1099\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1099\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e1099\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e1099\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSuper-Plasticizer\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1.60%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1.60%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e1.60%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e1.60%\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab4\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 4\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eSummary of the specimen along with the size and exposure/curing period\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"7\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c7\" colnum=\"7\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003eTests\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003eCylinder Size\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003eExposer/Curing Days\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"4\" nameend=\"c7\" namest=\"c4\"\u003e \u003cp\u003eMix ID\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eOL-00\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003eOL-100\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c6\"\u003e \u003cp\u003eLL-00\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c7\"\u003e \u003cp\u003eLL-100\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\" morerows=\"3\" rowspan=\"4\"\u003e \u003cp\u003eCompression\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\" morerows=\"3\" rowspan=\"4\"\u003e \u003cp\u003e100 mm dia. \u0026times; 200 mm height\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e90\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e180\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e270\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e365\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\" morerows=\"3\" rowspan=\"4\"\u003e \u003cp\u003eSplitting Tensile\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\" morerows=\"3\" rowspan=\"4\"\u003e \u003cp\u003e100 mm dia. \u0026times; 200 mm height\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e90\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e180\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e270\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e365\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003ePull-out Test\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003e100 mm dia. \u0026times; 200 mm height\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e28\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eWater Permeability\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e100 mm dia. \u0026times; 200 mm height\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e28\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSorptivity\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e100 \u0026times; 200 cylinders were cut into 100 \u0026times; 50mm disc\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e28\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec5\" class=\"Section2\"\u003e \u003ch2\u003e2.3 Experimental Setup\u003c/h2\u003e \u003cdiv id=\"Sec6\" class=\"Section3\"\u003e \u003ch2\u003e2.3.1 Compressive Strength\u003c/h2\u003e \u003cp\u003eCylindrical specimens with a diameter of 100 mm and a height of 200 mm were tested by ASTM C39-21 [\u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e30\u003c/span\u003e] to evaluate the compressive strength of the OPC and LC\u003csup\u003e3\u003c/sup\u003e-50 concrete mixtures [\u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e31\u003c/span\u003e]. The compression testing machine with a 2000 kN load capacity and an accuracy of 1% is used for the compression testing of cylinders (refer to Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e). The specimens were tested after 90, 180, 270, and 360 days of exposure to CO\u003csub\u003e2\u003c/sub\u003e in an accelerated environment.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec7\" class=\"Section3\"\u003e \u003ch2\u003e2.3.2 Splitting Tensile Test\u003c/h2\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eASTM C496/ C496M-11 [\u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e32\u003c/span\u003e] was followed while conducting the split tensile test. For split tensile strength testing, cylindrical samples with dimensions of 200 mm in height and 100 mm in diameter were cast. Concrete samples are removed from the mould and placed in the curing tank to cure for 28 days then placed in the carbonation chamber for accelerated 90, 180, 270, and 360 days (i.e. before being tested for split tensile strength. The test was conducted using a universal testing machine with a 500 kN limit (refer to Fig.\u0026nbsp;4).\u003c/p\u003e \u003cp\u003eFigure 4: Setup for the determination of the split tensile test of concrete cylinders\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec8\" class=\"Section3\"\u003e \u003ch2\u003e2.3.4 Pull-out Test\u003c/h2\u003e \u003cp\u003eThe basic concept behind pull-out testing is to determine how much force is required to remove a steel rod embedded in concrete. To assess the pull-out strength of hardened concrete, it measures the amount of force needed to remove an implanted rod. Three concrete cylinders measuring 100 mm in diameter and 200 mm in height were used, along with steel rods that had been embedded 100 mm into the specimen and had a rod length of 850 mm. UTM with a 500 kN capacity was used for the displacement control with a loading rate of 0.5 mm/min following ASTM C900 (refer to Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e5\u003c/span\u003e) [\u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e33\u003c/span\u003e].\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec9\" class=\"Section3\"\u003e \u003ch2\u003e2.3.5 Carbonation\u003c/h2\u003e \u003cp\u003eThe carbonation test is a pH test that reveals the pH depth, hence reducing the impact of carbonation on the concrete element. A carbonation test is used to determine the level of CO\u003csub\u003e2\u003c/sub\u003e infiltration in concrete. For this test, cylinder samples were placed inside an accelerated carbonation chamber and kept there for a specified duration of time. In the experiment, a 5% concentration of CO\u003csub\u003e2\u003c/sub\u003e was used for this test (refer to Fig.\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e6\u003c/span\u003e). The temperature was 23\u0026deg;C with a humidity level of 55%, as recommended by Dhir et al. [\u003cspan citationid=\"CR34\" class=\"CitationRef\"\u003e34\u003c/span\u003e]. It is acceptable to say that 11 hours of accelerated exposure to concrete in the carbonation chamber is equivalent to one month of natural exposure to the environment [\u003cspan citationid=\"CR34\" class=\"CitationRef\"\u003e34\u003c/span\u003e]. In an accelerated carbonation chamber, concrete samples from OPC and LC\u003csup\u003e3\u003c/sup\u003e-50 were exposed for 34, 68, 102, and 136 hours, respectively, simulating 3, 6, 9, and 12 months of natural exposure. The process of accelerated carbonation is highlighted as a positive approach for capturing CO\u003csub\u003e2\u003c/sub\u003e and a fascinating method to proactively reduce the alkalinity of the cement matrix. This is achieved by utilizing the Ca(OH)\u003csub\u003e2\u003c/sub\u003e ions present in the cement paste, leading to the densification of the matrix and a reduction in porosity. Additionally, the accelerated carbonation process was observed to involve the consumption of C-S-H (calcium silicate hydrate) and calcium sulfoaluminates (such as ettringite) [\u003cspan citationid=\"CR35\" class=\"CitationRef\"\u003e35\u003c/span\u003e].\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec10\" class=\"Section3\"\u003e \u003ch2\u003e2.3.6 Water Permeability\u003c/h2\u003e \u003cp\u003eIt is the property of a fluid to flow through interconnected pores. It is substantial in terms of durability because it causes reinforcement to corrode while allowing carbonation and other substances to penetrate the concrete. German Standard DIN 1048 [\u003cspan citationid=\"CR36\" class=\"CitationRef\"\u003e36\u003c/span\u003e] was used to determine it. Following a 28-day curing period, the equipment was assembled using three concrete cylinders measuring 100 mm in diameter and 200 mm in height. 500 kPa (5 bar) of water pressure was continually applied for 72 hours in the water permeability apparatus (refer to Fig.\u0026nbsp;\u003cspan refid=\"Fig6\" class=\"InternalRef\"\u003e7\u003c/span\u003e). To apply water pressure, a system with a water tank and an air compressor coupled by a valve to regulate pressure is used. The test outcome will be the average of the highest penetration levels attained from the three tested specimens.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec11\" class=\"Section3\"\u003e \u003ch2\u003e2.3.7 Sorptivity Test\u003c/h2\u003e \u003cp\u003eIn a uniform substance, the rate of absorption was assessed using water as the testing liquid, and the capillary absorption rate was measured. The procedure followed the guidelines outlined in ASTM C1585 [\u003cspan citationid=\"CR37\" class=\"CitationRef\"\u003e37\u003c/span\u003e]. Cylindrical specimens measuring 100 mm in diameter and 200 mm in height were made through casting and underwent a curing period of 28 days within a moist chamber. After they had cured, the specimens were cut into slices that were 50 mm thick (refer to Fig.\u0026nbsp;\u003cspan refid=\"Fig7\" class=\"InternalRef\"\u003e8\u003c/span\u003e), and the cylindrical surfaces of those pieces were then covered with epoxy. With a maximum height of 5 mm, these slices were placed just slightly above the specimen's base. A non-absorbent substance was used to properly seal the surface against liquid flow. Damp tissue was used to remove the extra surface moisture. The specimen was then weighed on a balance to determine the amount of water absorbed in 30 minutes. The amount of porosity was determined by multiplying the dry weight difference between the initial and final cylinder volumes after vacuum saturation. To standardize the data, which were obtained by plotting the rise in capillary mass over the square root of time, the pitch was adjusted to represent the total amount of water absorbed. This was divided by the thickness of the specimen determined by the sorption index [\u003cspan citationid=\"CR38\" class=\"CitationRef\"\u003e38\u003c/span\u003e].\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e \u003c/div\u003e"},{"header":"3. Result \u0026 Discussion","content":"\u003cdiv id=\"Sec13\" class=\"Section2\"\u003e \u003ch2\u003e3.1 Effect of Carbonation\u003c/h2\u003e \u003cdiv id=\"Sec14\" class=\"Section3\"\u003e \u003ch2\u003e3.1.1 On the Compressive Strengths\u003c/h2\u003e \u003cp\u003eTo better understand the impact of carbon dioxide (CO\u003csub\u003e2\u003c/sub\u003e) exposure on the compressive strength of these specimens, controlled environments were maintained in carbonation, and their performance was monitored throughout 90, 180, 270, and 365 days. The specimens were cylindrical having a 100 mm diameter and height of 200 mm were tested for failure under the application of compressive load as per standard. In this section the comparison of compressive strength was discussed based on aggregate replacement, curing days, and binder type.\u003c/p\u003e \u003cdiv id=\"Sec15\" class=\"Section4\"\u003e \u003ch2\u003e3.1.1.1 Comparison Based on Aggregate Replacement\u003c/h2\u003e \u003cp\u003eThe average compression test result for the cylinder cast with OPC and LC3-50 after exposure to CO\u003csub\u003e2\u003c/sub\u003e is presented in Fig.\u0026nbsp;\u003cspan refid=\"Fig8\" class=\"InternalRef\"\u003e9\u003c/span\u003e. For OPC concrete, compressive strength declined progressively with increased CO₂ exposure, irrespective of the aggregate type. A similar observation was reported by Ali et al. [\u003cspan citationid=\"CR39\" class=\"CitationRef\"\u003e39\u003c/span\u003e]. The normal weight aggregate (NWA) specimens initially achieved a peak strength of 55.4 MPa, while substituting lightweight aggregates (LWA) caused a 38% reduction. Post-exposure strength reductions for NWA specimens were 1.5%, 7.5%, 8.5%, and 14.3% after 90, 180, 270, and 365 days, respectively. In contrast, LWA specimens exhibited lower reductions of 1.3%, 2%, 3.5%, and 4.1%. The strength reduction of LWA specimens compared to NWA specimens after curing can be attributed to the lower mechanical properties of lightweight aggregates. However, under CO₂ exposure, LWA specimens demonstrated significantly improved performance. Carbonation leads to the formation of calcium carbonate from calcium hydroxide in the cement matrix, reducing alkalinity and disrupting the pore structure. The improved resistance to carbonation in lightweight concrete (LWC) was attributed to its denser pore structure, lower water-to-binder ratio, and higher cement content [\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e]. The enhanced performance of LWA specimens is linked to their physical characteristics, such as a denser microstructure, rough surface texture, and higher pH, which collectively limit CO₂ diffusion and reduce carbonation effects.\u003c/p\u003e \u003cp\u003eSimilarly, LC\u003csup\u003e3\u003c/sup\u003e-50 concrete exhibited a peak strength of 56.8 MPa with NWA, which decreased by 33% with LWA. Upon CO₂ exposure, NWA specimens showed strength losses of 8%, 9.2%, 14.1%, and 17.5% over the same durations, while LWA specimens demonstrated greater resistance, with reductions remaining below 4%. LC\u003csup\u003e3\u003c/sup\u003e-50 concrete specimens exhibited higher initial strength compared to OPC mixes, likely due to the synergistic pozzolanic reaction between calcined clay and limestone. This reaction generates additional C-S-H gel phases, improving the matrix's microstructural density and strength. For LWA specimens, reductions below 4% indicate that lightweight aggregates effectively mitigate carbonation effects. Additionally, the enhanced pH stability provided by LC\u003csup\u003e3\u003c/sup\u003e-50's cement chemistry complements the aggregates' properties, further reducing carbonation-induced deterioration. The enhanced performance of LWA specimens is linked to their physical characteristics, such as a denser microstructure, rough surface texture, and higher pH, which collectively limit CO₂ diffusion and reduce carbonation effects.\u003c/p\u003e \u003cp\u003eSimilarly, LC\u003csup\u003e3\u003c/sup\u003e-50 concrete exhibited a peak strength of 56.8 MPa with NWA, which decreased by 33% with LWA. Upon CO₂ exposure, NWA specimens showed strength losses of 8%, 9.2%, 14.1%, and 17.5% over the same durations, while LWA specimens demonstrated greater resistance, with reductions remaining below 4%. LC\u003csup\u003e3\u003c/sup\u003e-50 concrete specimens exhibited higher initial strength compared to OPC mixes, likely due to the synergistic pozzolanic reaction between calcined clay and limestone. This reaction generates additional C-S-H gel phases, improving the matrix's microstructural density and strength. For LWA specimens, reductions below 4% indicate that lightweight aggregates effectively mitigate carbonation effects. Additionally, the enhanced pH stability provided by LC\u003csup\u003e3\u003c/sup\u003e-50's cement chemistry complements the aggregates' properties, further reducing carbonation-induced deterioration.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec16\" class=\"Section4\"\u003e \u003ch2\u003e3.1.1.2 Comparison Based on Binder Type\u003c/h2\u003e \u003cp\u003eFor the case of compressive strengths exhibited after carbonation, specimens were prepared with 0% and 100% replacements of aggregates. The compressive strengths for OPC and LC\u003csup\u003e3\u003c/sup\u003e-50 specimens prepared with 0% aggregate replacement, it was found that OPC specimens exhibited higher compressive strength when natural aggregates were used as compared to LC\u003csup\u003e3\u003c/sup\u003e-50 specimens (refer to Fig.\u0026nbsp;\u003cspan refid=\"Fig9\" class=\"InternalRef\"\u003e10\u003c/span\u003e), whereas the specimens prepared with 100% lightweight aggregates, it was found that LC\u003csup\u003e3\u003c/sup\u003e-50 specimens exhibited higher compressive strengths as compared to OPC specimens.\u003c/p\u003e \u003cp\u003eIn all cases, it was observed that as exposure time increased, compressive strength decreased. This trend aligns with past literature; Mehmood et al. [\u003cspan citationid=\"CR40\" class=\"CitationRef\"\u003e40\u003c/span\u003e] also observed similar results when using recycled aggregates at different replacement levels. Comparing specimens LL-100 with LL-0, LL-100 exhibits a 10\u0026ndash;11% greater compressive strength. In previous studies [\u003cspan citationid=\"CR41\" class=\"CitationRef\"\u003e41\u003c/span\u003e, \u003cspan citationid=\"CR42\" class=\"CitationRef\"\u003e42\u003c/span\u003e], it was observed that specimens exposed directly to carbonation experienced an increase in compressive strength. This phenomenon can be attributed to the formation of precipitates of calcium carbonate, rather than portlandite. However, when specimens were subjected to water curing initially, portlandite was formed. Subsequent exposure to carbonation led to a reduction in portlandite content, thereby decreasing alkalinity levels. In conditions of low alkalinity, the stability of the CSH gel was compromised, consequently resulting in a decrease in strength [\u003cspan citationid=\"CR43\" class=\"CitationRef\"\u003e43\u003c/span\u003e].\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv id=\"Sec17\" class=\"Section3\"\u003e \u003ch2\u003e3.1.2 On the Splitting Tensile Strengths\u003c/h2\u003e \u003cp\u003eTo study the splitting tensile behavior of specimens cast with OPC and LC\u003csup\u003e3\u003c/sup\u003e-50 concrete after carbon dioxide (CO\u003csub\u003e2\u003c/sub\u003e) exposure the specimens were placed in the carbonation chamber for 90, 180, 270, and 365 days. In this section, the comparison of compressive strength was carried out based on aggregate replacement, curing days, and binder type.\u003c/p\u003e \u003cdiv id=\"Sec18\" class=\"Section4\"\u003e \u003ch2\u003e3.1.2.1 Comparison Based on Aggregate Replacement\u003c/h2\u003e \u003cp\u003eThe average tensile test results for cylinders cast with OPC and LC\u003csup\u003e3\u003c/sup\u003e-50 after exposure to CO\u003csub\u003e2\u003c/sub\u003e are presented in Fig.\u0026nbsp;\u003cspan refid=\"Fig10\" class=\"InternalRef\"\u003e11\u003c/span\u003e. By observing the result, it was found that the tensile strength decreases as the exposure time increases irrespective of the aggregate type. In their study on recycled aggregate, Mehmood et al. [\u003cspan citationid=\"CR40\" class=\"CitationRef\"\u003e40\u003c/span\u003e] observed a similar trend in their results.\u003c/p\u003e \u003cp\u003eFor OPC concrete, the tensile strength decreased with increasing exposure time, regardless of the aggregate type. Specimens cast with 100% natural aggregates initially exhibited good strength, reaching 4.33 MPa. However, using only lightweight aggregates resulted in a 31% reduction in maximum strength. After exposure to CO\u003csub\u003e2\u003c/sub\u003e for 90, 180, 270, and 365 days, specimens made with natural aggregates showed a continuous decline in tensile strength, with reductions of 4%, 8.3%, 8.7%, and 14.6%, respectively, compared to the control specimens. In contrast, specimens made with 100% lightweight aggregates demonstrated a more resilient response, with much smaller decreases in tensile strength (0.1%, 1.1%, 2.9%, and 5.8% for the same exposure times). Throughout all exposure times, specimens made with natural aggregates consistently showed higher strength than those made with lightweight aggregates, with variations in strength ranging from 23\u0026ndash;28%.\u003c/p\u003e \u003cp\u003eFor LC\u003csup\u003e3\u003c/sup\u003e-50 concrete, after a 28-day curing period, specimens cast with natural aggregates reached a peak strength of 4.59 MPa, whereas those made with lightweight aggregates showed a significant 27% loss in strength. Upon CO\u003csub\u003e2\u003c/sub\u003e exposure, a decreasing trend in strength was observed for specimens cast with natural aggregates, with reductions of 4.9%, 8.5%, and 11.5% after 90, 180, and 365 days, respectively. Conversely, specimens made with 100% lightweight aggregates showed an unusual pattern, with tensile strength increasing by 15\u0026ndash;20% over the same exposure periods. This indicates that lightweight concrete exhibited improved resilience to CO\u003csub\u003e2\u003c/sub\u003e exposure compared to normal weight concrete (NWC).\u003c/p\u003e \u003cp\u003eThe interaction between the LC\u003csup\u003e3\u003c/sup\u003e-50 matrix and the lightweight aggregates explains this oddness. Because of their porous nature, lightweight aggregates may offer more pozzolanic reactions, perhaps improving the concrete's overall microstructure and resistance to CO\u003csub\u003e2\u003c/sub\u003e exposure. This phenomenon may possibly be linked to the LC\u003csup\u003e3\u003c/sup\u003e-50 mix's greater calcium silicate and aluminum phase concentrations, which could improve lightweight aggregates' pozzolanic activity and account for the strength enhancement that has been seen. Additionally, the tensile strength improvement is consistent with earlier research showing that LWC often has lower carbonation levels than NWC. This anomaly can be explained by the interaction between the lightweight aggregates and the LC\u003csup\u003e3\u003c/sup\u003e-50 matrix. Lightweight aggregates may provide additional pozzolanic reactions due to their porous nature, possibly enhancing the overall microstructure and resilience of the concrete under CO\u003csub\u003e2\u003c/sub\u003e exposure. This phenomenon could also be related to the higher levels of calcium silicate and aluminum phases within the LC\u003csup\u003e3\u003c/sup\u003e-50 mix, which may enhance the pozzolanic activity of lightweight aggregates and contribute to the observed strength gain. Lightweight concrete (LWC) of similar strength grade to normal weight concrete (NWC) exhibited lower carbonation levels compared to NWC mixes [\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e].\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec19\" class=\"Section4\"\u003e \u003ch2\u003e3.1.2.2 Comparison Based on Binder Type\u003c/h2\u003e \u003cp\u003eThe tensile strengths exhibited after carbonation, specimens prepared with 0% and 100% replacement were considered similar to the case of compressive tests. When comparing the tensile strengths for OPC and LC\u003csup\u003e3\u003c/sup\u003e-50 specimens, it was observed that LC\u003csup\u003e3\u003c/sup\u003e-50 specimens outperformed OPC specimens, irrespective of the percentage of replacement used (refer to Fig.\u0026nbsp;\u003cspan refid=\"Fig11\" class=\"InternalRef\"\u003e12\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eIn the case of OPC, the reduction of tensile strength after carbonation is 28%, whereas the reduction in LC\u003csup\u003e3\u003c/sup\u003e-50 is 7%, which is considerable. The performance of LC\u003csup\u003e3\u003c/sup\u003e-50 concrete specimens compared to OPC counterparts while using only 100% natural weight aggregates was noticeably improved by 5\u0026ndash;9%. From the observations made above, it can be concluded that the influence of lightweight aggregates is more dominant in LC\u003csup\u003e3\u003c/sup\u003e-50 for tensile strength as compared to compressive strengths. For all the cases, it was also found that as the exposure time increases, tensile strength decreases.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv id=\"Sec20\" class=\"Section2\"\u003e \u003ch2\u003e3.2 Pull-Out Strength\u003c/h2\u003e \u003cp\u003eFigure \u003cspan refid=\"Fig12\" class=\"InternalRef\"\u003e13\u003c/span\u003e shows the results of pullout tests conducted on specimens at 7 and 28 days of curing. In general, it was observed that specimens exhibit higher pull-out strength at 28 days of curing as compared to that observed at 7 days of curing. When tested at 28 days, it was observed that specimens prepared with LC\u003csup\u003e3\u003c/sup\u003e-50 exhibited higher pull-out strength as compared to OPC when natural aggregates were used. Earlier studies have indicated that LC\u003csup\u003e3\u003c/sup\u003e-50 concrete possesses a denser microstructure characterized by reduced porosity and an improved ratio of splitting to compressive strength when compared to OPC concrete. Additionally, LC\u003csup\u003e3\u003c/sup\u003e-50 concrete exhibits a higher elastic modulus and greater bond stress between the concrete and steel bar. Notably, LC\u003csup\u003e3\u003c/sup\u003e-50 concrete demonstrates a higher bond-slip stiffness in comparison to OPC concrete. [\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e]. When comparing the effect of the inclusion of lightweight aggregates on pull-out strength, it was observed that both OPC and LC\u003csup\u003e3\u003c/sup\u003e-50 specimens exhibit almost similar behavior.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec21\" class=\"Section2\"\u003e \u003ch2\u003e3.3 Water Permeability\u003c/h2\u003e \u003cp\u003eThe permeability tests were conducted for OPC and LC\u003csup\u003e3\u003c/sup\u003e-50 specimens prepared with 0% and 100% replacement. When comparing the type of cement composition, it was observed that OPC specimens exhibit higher permeability approximately 70% higher as compared to LC\u003csup\u003e3\u003c/sup\u003e-50 specimens (refer to Fig.\u0026nbsp;\u003cspan refid=\"Fig13\" class=\"InternalRef\"\u003e14\u003c/span\u003e). This may be due to the presence of voids in the concrete matrix which provides permeability. An Indian pore structure study suggests that the LC\u003csup\u003e3\u003c/sup\u003e-50 system had a higher resistivity. Its paste phase may have a higher ionic transport barrier. Hence, it has lower inherent permeability [\u003cspan citationid=\"CR44\" class=\"CitationRef\"\u003e44\u003c/span\u003e]. The results indicate that the utilization of the LC\u003csup\u003e3\u003c/sup\u003e-50 blend is viable for various applications involving water exposure or underwater placement of concrete. In such scenarios, the need for additional water protection measures, like crystalline waterproofing, can be reduced compared to OPC cement. Consequently, this reduction in the usage of supplementary materials leads to increased cost-effectiveness for the project. When comparing the effect of using lightweight aggregates, it was observed that for 100% replacement of natural aggregates with lightweight aggregates, permeability is decreased significantly by about 50%, irrespective of the type of concrete used.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec22\" class=\"Section2\"\u003e \u003ch2\u003e3.4 Sorptivity\u003c/h2\u003e \u003cp\u003eFigure \u003cspan refid=\"Fig14\" class=\"InternalRef\"\u003e15\u003c/span\u003e gives the absorption capacity of normal-weight and lightweight specimens prepared with LC\u003csup\u003e3\u003c/sup\u003e-50 and OPC. It was observed that specimens prepared with OPC exhibited higher sorptivity, irrespective of the type of aggregates used. When comparing the effect of using different types of cement, it was observed that lightweight concrete prepared with OPC exhibits a 21% higher rate of absorption as compared to LC\u003csup\u003e3\u003c/sup\u003e-50 specimens. According to an Indian study, the adsorption rate is lowered by the pozzolanic and filler impact brought on by SCM addition and more sinuous pores in LC\u003csup\u003e3\u003c/sup\u003e-50 mixtures of concrete and due to contraction in pore diameters at an initial point of the concrete that affects in immediate augmentation of durability performance for concrete [\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e].\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e"},{"header":"4. Conclusion","content":"\u003cp\u003eBased on the comprehensive experimental research on the usage of lightweight aggregate replacements for LC\u003csup\u003e3\u003c/sup\u003e-50 and concrete and comparisons with OPC and LC\u003csup\u003e3\u003c/sup\u003e-50 based concretes, the following are the conclusions drawn:\u003c/p\u003e \u003cp\u003e \u003col\u003e \u003cspan\u003e \u003cli\u003e \u003cp\u003eCompressive strength and splitting tensile strength of concrete decreased with longer CO\u003csub\u003e2\u003c/sub\u003e exposure, irrespective of aggregate type. Over the same exposure periods, concrete containing lightweight aggregates responded to CO\u003csub\u003e2\u003c/sub\u003e exposure more favorably, showing lower reductions in compressive strength (ranging from 1.3\u0026ndash;4.1%) and relatively slight declines in tensile strength (ranging from 0.1\u0026ndash;5.8%).\u003c/p\u003e \u003c/li\u003e \u003c/span\u003e \u003cspan\u003e \u003cli\u003e \u003cp\u003eIn comparison to LC\u003csup\u003e3\u003c/sup\u003e-50 specimens using natural aggregates, OPC specimens exhibited higher compressive strengths. Conversely, LC\u003csup\u003e3\u003c/sup\u003e-50 specimens incorporating 100% lightweight aggregates showed higher strengths than OPC counterparts, with all cases experiencing a decrease in strength with an increase in CO\u003csub\u003e2\u003c/sub\u003e exposure time. Additionally, 100% lightweight aggregates resulted in 10\u0026ndash;11% higher strength in comparison to 0% lightweight aggregates.\u003c/p\u003e \u003c/li\u003e \u003c/span\u003e \u003cspan\u003e \u003cli\u003e \u003cp\u003eIn terms of tensile behavior, LC\u003csup\u003e3\u003c/sup\u003e-50 concrete consistently demonstrated higher tensile strength than OPC regardless of replacement percentages. Furthermore, after carbonation, LC\u003csup\u003e3\u003c/sup\u003e-50 showed a far lesser reduction in tensile strength than OPC\u0026mdash;a decline of 7% in LC\u003csup\u003e3\u003c/sup\u003e-50 against 28% in OPC. Compared to their OPC counterparts, LC\u003csup\u003e3\u003c/sup\u003e-50 specimens with 100% natural aggregates showed an improvement of 5\u0026ndash;9%. It's interesting to note that lightweight aggregates had a greater impact on LC\u003csup\u003e3\u003c/sup\u003e-50's tensile strength than on its compressive strength. Longer exposure times consistently resulted in a drop in tensile strength.\u003c/p\u003e \u003c/li\u003e \u003c/span\u003e \u003cspan\u003e \u003cli\u003e \u003cp\u003eIn terms of water resistance and pull-out strength, LC\u003csup\u003e3\u003c/sup\u003e-50 concrete outperforms OPC concrete. LC\u003csup\u003e3\u003c/sup\u003e-50's denser structure and improved bonding contribute to its higher pull-out strength and lower permeability. Lightweight aggregates also reduce permeability significantly in both types of concrete. Although OPC has higher sorptivity, LC\u003csup\u003e3\u003c/sup\u003e-50's advantages make it a promising choice for stronger and more durable construction, especially when combined with lightweight aggregates.\u003c/p\u003e \u003c/li\u003e \u003c/span\u003e \u003c/ol\u003e \u003c/p\u003e"},{"header":"Declarations","content":"\u003ch2\u003eAuthor Contribution\u003c/h2\u003e\u003cp\u003eSyed Fahad Hussain carried out the experimental investigation and drafted the manuscript under the guidance of Prof Dr Tehmina Ayub. Dr Tariq Jamil was the Principal Investigator who secured financial support from the Higher Education Commission of Pakistan, National Research Program for Universities (NRPU) Project no. 14074 entitled \u0026ldquo;Development of Cost-Effective Structural Concrete Formulation using Limestone Calcined Clay Based LC3 Cement Blend with Domestic Resources and its Application in a Pilot Project.\u0026rdquo; The authors are grateful for the valuable input from Prof. Dr. Karen Scrivener, Head of the Laboratory of Construction Materials, Swiss Federal Institute of Technology (EPFL) based in Lausanne, Switzerland.\u003c/p\u003e\u003ch2\u003eAcknowledgement\u003c/h2\u003e\u003cp\u003eThe authors are grateful and acknowledge the support from the Higher Education Commission of Pakistan, National Research Program for Universities (NRPU) Project no. 14074 entitled \u0026ldquo;Development of Cost-Effective Structural Concrete Formulation using Limestone Calcined Clay Based LC3 Cement Blend with Domestic Resources and its Application in a Pilot Project.\u0026rdquo; The authors are grateful for the valuable input from Prof. Dr. Karen Scrivener, Head of the Laboratory of Construction Materials, Swiss Federal Institute of Technology (EPFL) based in Lausanne, Switzerland.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eMahmood, W., A.-u.-R. Khan, and T. Ayub, \u003cem\u003eMechanical and durability properties of concrete containing recycled concrete aggregates.\u003c/em\u003e Iranian Journal of Science and Technology, Transactions of Civil Engineering, 2021: p. 1-20.\u003c/li\u003e\n\u003cli\u003eEnvironment, U., et al., \u003cem\u003eEco-efficient cements: Potential economically viable solutions for a low-CO2 cement-based materials industry.\u003c/em\u003e Cement and concrete Research, 2018. \u003cstrong\u003e114\u003c/strong\u003e: p. 2-26.\u003c/li\u003e\n\u003cli\u003eAyub, A., et al., \u003cem\u003eMechanical and Durability Properties of High-Strength Limestone Calcined Clay Cement (LC3) Concrete Containing Waste Glass Powder.\u003c/em\u003e Iranian Journal of Science and Technology, Transactions of Civil Engineering, 2023: p. 1-20.\u003c/li\u003e\n\u003cli\u003eImbabi, M.S., C. Carrigan, and S. McKenna, \u003cem\u003eTrends and developments in green cement and concrete technology.\u003c/em\u003e International Journal of Sustainable Built Environment, 2012. \u003cstrong\u003e1\u003c/strong\u003e(2): p. 194-216.\u003c/li\u003e\n\u003cli\u003eAlexander, M., A. Bentur, and S. Mindess, \u003cem\u003eDurability of concrete: design and construction\u003c/em\u003e. Vol. 20. 2017: CRC Press.\u003c/li\u003e\n\u003cli\u003eHussain, S.M.F., et al., \u003cem\u003eInitial search for low grade clay in Pakistan for producing LC3 ecofriendly cement.\u003c/em\u003e Low-carbon Materials and Green Construction, 2023. \u003cstrong\u003e1\u003c/strong\u003e(1): p. 15.\u003c/li\u003e\n\u003cli\u003eDavidovits, J., \u003cem\u003eGlobal warming impact on the cement and aggregates industries.\u003c/em\u003e World resource review, 1994. \u003cstrong\u003e6\u003c/strong\u003e(2): p. 263-278.\u003c/li\u003e\n\u003cli\u003eScrivener, K., \u003cem\u003eEco-efficient cements: No magic bullet needed.\u003c/em\u003e Glob. Cem. Mag, 2019: p. 10-14.\u003c/li\u003e\n\u003cli\u003eMarangu, J.M., \u003cem\u003ePhysico-chemical properties of Kenyan made calcined Clay-Limestone cement (LC3).\u003c/em\u003e Case Studies in Construction Materials, 2020. \u003cstrong\u003e12\u003c/strong\u003e: p. e00333.\u003c/li\u003e\n\u003cli\u003eMuleya, F., et al., \u003cem\u003ePARTIAL REPLACEMENT OF CEMENT WITH RICE HUSK ASH IN CONCRETE PRODUCTION: AN EXPLORATORY COST-BENEFIT ANALYSIS FOR LOW-INCOME COMMUNITIES.\u003c/em\u003e Engineering Management in Production \u0026amp; Services, 2021. \u003cstrong\u003e13\u003c/strong\u003e(3).\u003c/li\u003e\n\u003cli\u003eAkan, M.\u0026Ouml;.A., D.G. Dhavale, and J. Sarkis, \u003cem\u003eGreenhouse gas emissions in the construction industry: An analysis and evaluation of a concrete supply chain.\u003c/em\u003e Journal of Cleaner Production, 2017. \u003cstrong\u003e167\u003c/strong\u003e: p. 1195-1207.\u003c/li\u003e\n\u003cli\u003eScrivener, K., et al., \u003cem\u003eCalcined clay limestone cements (LC3).\u003c/em\u003e Cement and Concrete Research, 2018. \u003cstrong\u003e114\u003c/strong\u003e: p. 49-56.\u003c/li\u003e\n\u003cli\u003eSheikh, M.D., et al., \u003cem\u003eComparative Study on LC 3-50 with OPC Concrete Using Raw Materials from Pakistan.\u003c/em\u003e Advances in Materials Science and Engineering, 2023. \u003cstrong\u003e2023\u003c/strong\u003e.\u003c/li\u003e\n\u003cli\u003eScrivener, K., et al., \u003cem\u003eImpacting factors and properties of limestone calcined clay cements (LC3).\u003c/em\u003e Green Materials, 2018. \u003cstrong\u003e7\u003c/strong\u003e(1): p. 3-14.\u003c/li\u003e\n\u003cli\u003eLi, R. and H. Ye, \u003cem\u003eInfluence of alkalis on natural carbonation of limestone calcined clay cement pastes.\u003c/em\u003e Sustainability, 2021. \u003cstrong\u003e13\u003c/strong\u003e(22): p. 12833.\u003c/li\u003e\n\u003cli\u003eHuang, Z.-y., et al., \u003cem\u003eDevelopment of limestone calcined clay cement concrete in South China and its bond behavior with steel reinforcement.\u003c/em\u003e Journal of Zhejiang University-SCIENCE A, 2020. \u003cstrong\u003e21\u003c/strong\u003e(11): p. 892-907.\u003c/li\u003e\n\u003cli\u003eLu, J.-X., et al., \u003cem\u003eDevelopment of high performance lightweight concrete using ultra high performance cementitious composite and different lightweight aggregates.\u003c/em\u003e Cement and Concrete Composites, 2021. \u003cstrong\u003e124\u003c/strong\u003e: p. 104277.\u003c/li\u003e\n\u003cli\u003eMalik, M., S. Bhattacharyya, and S.V. Barai, \u003cem\u003eThermal and mechanical properties of concrete and its constituents at elevated temperatures: A review.\u003c/em\u003e Construction and Building Materials, 2021. \u003cstrong\u003e270\u003c/strong\u003e: p. 121398.\u003c/li\u003e\n\u003cli\u003eAlexander, M. and S. Mindess, \u003cem\u003eAggregates in concrete\u003c/em\u003e. 2005: CRC Press.\u003c/li\u003e\n\u003cli\u003eLo, T., W. Tang, and A. Nadeem, \u003cem\u003eComparison of carbonation of lightweight concrete with normal weight concrete at similar strength levels.\u003c/em\u003e Construction and Building Materials, 2008. \u003cstrong\u003e22\u003c/strong\u003e(8): p. 1648-1655.\u003c/li\u003e\n\u003cli\u003eTeo, D., et al., \u003cem\u003eLightweight concrete made from oil palm shell (OPS): Structural bond and durability properties.\u003c/em\u003e Building and environment, 2007. \u003cstrong\u003e42\u003c/strong\u003e(7): p. 2614-2621.\u003c/li\u003e\n\u003cli\u003eAlujas, A., et al., \u003cem\u003ePozzolanic reactivity of low grade kaolinitic clays: Influence of calcination temperature and impact of calcination products on OPC hydration.\u003c/em\u003e Applied Clay Science, 2015. \u003cstrong\u003e108\u003c/strong\u003e: p. 94-101.\u003c/li\u003e\n\u003cli\u003eDhandapani, Y., et al., \u003cem\u003eMechanical properties and durability performance of concretes with Limestone Calcined Clay Cement (LC3).\u003c/em\u003e Cement and Concrete Research, 2018. \u003cstrong\u003e107\u003c/strong\u003e: p. 136-151.\u003c/li\u003e\n\u003cli\u003eSree, S.K., et al. \u003cem\u003eExperimental studies on mechanical and durability characteristics of lc3 concrete\u003c/em\u003e. in \u003cem\u003eIOP Conference Series: Materials Science and Engineering\u003c/em\u003e. 2021. IOP Publishing.\u003c/li\u003e\n\u003cli\u003eJavadi, A., et al., \u003cem\u003eWorking mechanisms and design principles of comb-like polycarboxylate ether superplasticizers in cement hydration: quantitative insights for a series of well-defined copolymers.\u003c/em\u003e ACS Sustainable Chemistry \u0026amp; Engineering, 2021. \u003cstrong\u003e9\u003c/strong\u003e(25): p. 8354-8371.\u003c/li\u003e\n\u003cli\u003eAstm, A., \u003cem\u003eStandard test method for relative density (specific gravity) and absorption of coarse aggregate.\u003c/em\u003e ASTM West Conshohocken, PA, 2015.\u003c/li\u003e\n\u003cli\u003eStandard, B., \u003cem\u003eBS 812-110: 1990 Testing Aggregates-Part 110: Methods for Determination of Aggregate Crushing Value (ACV).\u003c/em\u003e Bsi, Uk, 1990.\u003c/li\u003e\n\u003cli\u003eAashto, T., \u003cem\u003eStandard method of test for resistance to degradation of small-size coarse aggregate by abrasion and impact in the Los Angeles machine.\u003c/em\u003e American Association of State Highway and Transportation Officials, 2002.\u003c/li\u003e\n\u003cli\u003e, A.C., \u003cem\u003eReport on High-Strength Concrete (ACI 363R-10)\u003c/em\u003e. 2010: ACI.\u003c/li\u003e\n\u003cli\u003eC39/C39M-21, A., \u003cem\u003eStandard Test Method for Compressive Strength of Cylindrical Concrete Specimens\u003c/em\u003e. 2021, American Standard Test Method: West Conshohocken, Penn, USA.\u003c/li\u003e\n\u003cli\u003eConcrete, A.I.C.C.o. and C. Aggregates, \u003cem\u003eStandard test method for compressive strength of cylindrical concrete specimens\u003c/em\u003e. 2014: ASTM international.\u003c/li\u003e\n\u003cli\u003eStandard, A., \u003cem\u003eC496/c496m (2011) Standard Test Method for Splitting Tensile Strength of Cylindrical Concrete Specimens.\u003c/em\u003e Annual Book of ASTM Standards, 2004. \u003cstrong\u003e9\u003c/strong\u003e.\u003c/li\u003e\n\u003cli\u003eRichards, O., \u003cem\u003ePullout strength of concrete\u003c/em\u003e. 1977: ASTM International.\u003c/li\u003e\n\u003cli\u003eDhir, R., P. Hewlett, and Y. Chan, \u003cem\u003eNear-surface characteristics of concrete: prediction of carbonation resistance.\u003c/em\u003e Magazine of Concrete Research, 1989. \u003cstrong\u003e41\u003c/strong\u003e(148): p. 137-143.\u003c/li\u003e\n\u003cli\u003ePizzol, V.D., et al., \u003cem\u003eEffect of accelerated carbonation on the microstructure and physical properties of hybrid fiber-cement composites.\u003c/em\u003e Minerals Engineering, 2014. \u003cstrong\u003e59\u003c/strong\u003e: p. 101-106.\u003c/li\u003e\n\u003cli\u003eStandard, G., \u003cem\u003eDIN 1048\u0026ndash;\u0026ndash;test methods of concrete impermeability to water: Part 2.\u003c/em\u003e Deutscher Institute Fur Normung, Germany, 1978.\u003c/li\u003e\n\u003cli\u003eAstm, C., \u003cem\u003e1585-04. Standard test method for measurement of rate of absorption of water by hydraulic-cement concretes.\u003c/em\u003e ASTM International, 2004.\u003c/li\u003e\n\u003cli\u003eBu, Y., R. Spragg, and W. Weiss, \u003cem\u003eComparison of the pore volume in concrete as determined using ASTM C642 and vacuum saturation.\u003c/em\u003e Advances in Civil Engineering Materials, 2014. \u003cstrong\u003e3\u003c/strong\u003e(1): p. 308-315.\u003c/li\u003e\n\u003cli\u003eAli, M., M.S. Abdullah, and S.A. Saad, \u003cem\u003eEffect of calcium carbonate replacement on workability and mechanical strength of Portland cement concrete.\u003c/em\u003e Advanced materials research, 2015. \u003cstrong\u003e1115\u003c/strong\u003e: p. 137-141.\u003c/li\u003e\n\u003cli\u003eMahmood, W., A.-u.-R. Khan, and T. Ayub, \u003cem\u003eCarbonation resistance in ordinary Portland cement concrete with and without recycled coarse aggregate in natural and simulated environment.\u003c/em\u003e Sustainability, 2021. \u003cstrong\u003e14\u003c/strong\u003e(1): p. 437.\u003c/li\u003e\n\u003cli\u003eMerah, A. and B. Krobba, \u003cem\u003eEffect of the carbonatation and the type of cement (CEM I, CEM II) on the ductility and the compressive strength of concrete.\u003c/em\u003e Construction and Building Materials, 2017. \u003cstrong\u003e148\u003c/strong\u003e: p. 874-886.\u003c/li\u003e\n\u003cli\u003eKim, J.-K., et al., \u003cem\u003eEffect of carbonation on the rebound number and compressive strength of concrete.\u003c/em\u003e Cement and Concrete Composites, 2009. \u003cstrong\u003e31\u003c/strong\u003e(2): p. 139-144.\u003c/li\u003e\n\u003cli\u003eZajac, M., et al., \u003cem\u003eCO2 mineralization methods in cement and concrete industry.\u003c/em\u003e Energies, 2022. \u003cstrong\u003e15\u003c/strong\u003e(10): p. 3597.\u003c/li\u003e\n\u003cli\u003eDhandapani, Y. and M. Santhanam, \u003cem\u003eAssessment of pore structure evolution in the limestone calcined clay cementitious system and its implications for performance.\u003c/em\u003e Cement and Concrete Composites, 2017. \u003cstrong\u003e84\u003c/strong\u003e: p. 36-47.\u003c/li\u003e\n\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":"iranian-journal-of-science-and-technology-transactions-of-civil-engineering","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"istc","sideBox":"Learn more about [Iranian Journal of Science and Technology, Transactions of Civil Engineering](http://link.springer.com/journal/40996)","snPcode":"40996","submissionUrl":"https://submission.nature.com/new-submission/40996/3","title":"Iranian Journal of Science and Technology, Transactions of Civil Engineering","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false},"keywords":"","lastPublishedDoi":"10.21203/rs.3.rs-5658989/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-5658989/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eThis study investigates the durability properties of OPC and LC\u003csup\u003e3\u003c/sup\u003e-50 concretes containing shale as lightweight coarse aggregates acquired from the Balochistan Province of Pakistan for structural concrete in comparison to natural coarse aggregates. The physical properties of shale aggregates were initially assessed by performing crushing value, absorption, Impact value tests and specific gravity. In this study, two replacements for lightweight aggregate (0% and 100%) were investigated in OPC and LC\u003csup\u003e3\u003c/sup\u003e-50 concretes, which showed that the use of 100% lightweight in OPC and LC\u003csup\u003e3\u003c/sup\u003e-50-based concretes reduced compressive strength and splitting tensile strength by 60\u0026ndash;65% and 25\u0026ndash;30% in comparison to natural coarse aggregates without exposure to CO\u003csub\u003e2\u003c/sub\u003e. The reduction in the compressive and splitting tensile strengths due to CO\u003csub\u003e2\u003c/sub\u003e exposure was more OPC than LC\u003csup\u003e3\u003c/sup\u003e-50 concrete due to dense microstructure, which is also evident by the permeability results. The effect of CO\u003csub\u003e2\u003c/sub\u003e in reducing compressive and splitting tensile strengths at later ages (i.e. 270 and 365 days) becomes less than 90 and 180 days. The pull-out strength of OPC and LC\u003csup\u003e3\u003c/sup\u003e-50 concretes is almost similar at 7 and 28 days; however, the 28-day pull-out strength was observed to be 3 times higher than 7 days. Similarly, the permeability of LC\u003csup\u003e3\u003c/sup\u003e-50 concrete is better than OPC. Therefore, it can be concluded that LC\u003csup\u003e3\u003c/sup\u003e-50 in concrete improves durability and can be suitably used with 100% lightweight.\u003c/p\u003e","manuscriptTitle":"Durability Performance of Opc and Lc 3 -50 Concrete Containing Lightweight Aggregates","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2024-12-19 15:56:51","doi":"10.21203/rs.3.rs-5658989/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision 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