Strength Of Concrete Research Articles

Enhancing Compressive Strength in M45 Grade Concrete: A Comparative Evaluation of Micro-silica and Alccofine as Partial Cement Replacements

This study investigates the compressive strength and durability of M45 grade concrete using Micro-silica and Alccofine as partial replacements for cement. Experimental results indicate that Alccofine-based concrete achieves 28-day compressive strengths of up to 60.6 MPa at 10% replacement, outperforming Micro-silica-based mixes by 55.2 MPa. Alccofine also enhances workability, with slump values peaking at 144 mm and 135 mm for Micro-silica. The optimal replacement level for both materials is 10% by cement volume, where Alccofine’s dual pozzolanic-cementitious reactivity improves microstructure densification, reducing permeability and enhancing durability. These findings position Alccofine as a superior additive for high-strength concrete applications, offering significant mechanical and durability advantages.

Systematic assessment of the technical performance, durability, cost, and environmental impact of sustainable concrete incorporating fly ash and ground granulated blast‐furnace slag

Abstract River sand (RS), the main fine aggregate used in the manufacturing of mortar and concrete, has been chronically and seriously limited in availability in recent years. Additionally, numerous unfavorable problems with cement manufacture and use have been documented thus far. Given the aforementioned, identifying viable, alternative sources is essential to promoting the construction industry's sustainable growth. This study was developed to systematically assess the effect of fly ash (FA) as a replacement for RS (20–60 vol.%) and ground granulated blast‐furnace slag (GGBFS) as a substitution for cement (30 wt.%) on technical performance, microstructure, cost, and environmental impact of concrete. The resulting concrete exhibited increased compressive and flexural strengths up to 56.2% and 60.1%, respectively. Importantly, the proposed mixtures also offer both cost advantages and environmental benefits by reducing the total cost, CO2 emission, and energy consumption per unit strength of concrete. These findings underscore the respective potential of FA and GGBFS as sustainable alternatives to RS and traditional cement. Incorporating these two industrial by‐products delivers improved mechanical properties and enhanced durability (in terms of resistivity, ultrasonic pulse velocity, porosity, chloride permeability, water absorption, and drying shrinkage), promotes sustainable development in the construction industry, reduces environmental pollution, and conserves natural resources.

Predicting the compressive strength of concrete incorporating waste powders exposed to elevated temperatures utilizing machine learning

The addition of powders from waste construction materials as partial cement substitute in concrete represents a significant step toward green concrete construction. High temperatures have a substantial influence on concrete strength, resulting in a reduction in mechanical properties. The prediction of the impacts of waste powders on concrete strength is an important topic in sustainable construction. Such models are needed to understand the complex interactions between waste materials’ powders and concrete strength. In this study, three machine learning approaches, extreme gradient boosting (XGBoost), random forest (RF), and M5P, were used for constructing the prediction model for the impact of elevated temperatures on the compressive strength of concrete modified by marble and granite construction waste powders as partial cement replacements in concrete. Dataset of 324 tested cubic specimens with four input variables, waste granite powder dose (GWP), waste marble powder (MWP), temperature (T), and duration (D) were chosen for developing the prediction models. The output was the concrete compressive strength (CS). MWP and GWP ranged between 0 and 9%, temperatures were ranged between 25 °C and 800 °C, and duration up to 2 h. Hyperparameters in the RF and XGB models were optimized using grid search. K-fold cross-validation and several statistical measures, including R2MAPE, RMSE, and MAE, were utilized to validate and check the accuracy of the proposed models. The developed models were evaluated against experimental data and previously established models. The XGB model demonstrated the highest R2 of 0.9989, alongside the lowest prediction errors: MAE of 0.1351 MPa, RMSE of 0.1842 MPa, and MAPE of 0.48%. The results showed that the XGB prediction model for the concrete compressive strength outperformed the other proposed models. The SHAP analysis, Individual Conditional Expectation (ICE), and Partial Dependence Plots (PDP) revealed that GWP and MWP positively influence the compressive strength, while the temperature exerts the most negative influence on predicting the compressive strength. Finally, a graphical user interface (GUI) for the compressive strength of concrete containing GWP and MWP subjected to elevated temperatures has been created, which may be of considerable assistance, guidance, and efficiency in research and construction industry contexts.

Use of fibres and surface treatment to improve the durability of concrete affected by sulphide mining

The aim of this research is to evaluate solutions to improve the durability of structural concrete used in sulphide mining. This type of environment is one of the most aggressive conditions in which a concrete structure can be placed, with pH values below 3 and high sulphate contents. These environments cause significant degradation of metallic and structural materials, resulting in mass loss and alteration of mechanical properties, a process that is accelerated by the intervention of acidophilic bacteria. In this work it is proposed to reinforce the concrete by incorporating polypropylene fibres and silica fume and to protect the specimens by applying two types of surface materials, one polyurethane base and the other asphalt base. Several laboratory tests were carried out to evaluate the fundamental mechanical properties and durability of concrete, including tensile and compressive strength tests In addition, Slake tests were carried out to analyse the degradation of different fragments, water permeability tests and pressure sandblasting tests to measure the behaviour of the concrete against abrasion. The results confirm an increase in the tensile strength of fibre-reinforced concrete of about 8%, while the use of both types of surface materials has been shown a zero water penetration depth, while at the same time significantly improves the performance against impact degradation and abrasion with a reduction in weight loss that obtained in the reference samples with Slake test which is reduced to only 0.45% with surface treatment with polyurethane, 1.01% with asphaltic treatment and 2.48% with fibres, and even no weight loss in the sandblasting tests on the samples treated with asphalt material.

Transforming plastic waste into durable concrete: a pathway to sustainable infrastructure

Plastics are petroleum-based products with significant environmental challenges due to disposal and degradation issues. This study focuses on the use of shredded (SrPCA) and crushed plastic coarse aggregate (CPCA) as partial replacements for natural coarse aggregate (NCA) in concrete to enhance environmental sustainability. Preliminary tests showed that SrPCA (292.50 kg/m3) and CPCA (779.50 kg/m3) are lightweight aggregates with water absorption values (SrPCA: 0.08%, CPCA: 0.15%) lower than NCA (0.63%). The Densities of plastic concrete ranged between 2359 and 2470 kg/m3, classifying them as normal-weight concrete. Moreover, the compressive strengths result (33.8–45.2 N/mm2) exceeded the designed grade of 30 N/mm2, while the flexural strengths (4.44–5.97 N/mm2) aligned with recommended values of 10–15% concrete compressive strength. The concrete water absorption results (1.91–3.25%) also met quality standards (< 5%). Therefore, the study suggests that replacing 10% of NCA with plastic aggregate can produce durable and high-quality concrete, promoting environmental sustainability.

Investigation of the Evolutionary Patterns of Pore Structures and Mechanical Properties During the Hydration Process of Basalt-Fiber-Reinforced Concrete

Recent studies primarily focus on how the fiber content and curing age influence the pore structure and strength of concrete. However, The interfacial bonding mechanism in basalt-fiber-reinforced concrete hydration remains unclear. The lack of a long-term performance-prediction model and insufficient research on multi-field coupling effects form key knowledge gaps, hindering the systematic optimal design and wider engineering applications of such materials. By integrating X-ray computed tomography (CT) with the watershed algorithm, this study proposes an innovative gray scale threshold method for pore quantification, enabling a quantitative analysis of pore structure evolution and its correlation with mechanical properties in basalt-fiber-reinforced concrete (BFRC) and normal concrete (NC). The results show the following: (1) Mechanical Enhancement: the incorporation of 0.2% basalt fiber by volume demonstrates significant enhancement in the mechanical performance index. At 28 days, BFRC exhibits compressive and splitting tensile strengths of 50.78 MPa and 4.07 MPa, surpassing NC by 19.88% and 43.3%, respectively. The early strength reduction in BFRC (13.13 MPa vs. 22.81 MPa for NC at 3 days) is attributed to fiber-induced interference through physical obstruction of cement particle hydration pathways, which diminishes as hydration progresses. (2) Porosity Reduction: BFRC demonstrates a 64.83% lower porosity (5.13%) than NC (11.66%) at 28 days, with microscopic analysis revealing a 77.5% proportion of harmless pores (&lt;1.104 × 107 μm3) in BFRC versus 67.6% in NC, driven by densified interfacial transition zones (ITZs). (3) Predictive Modeling: a two dimensional strength-porosity model and a three-dimensional age-dependent model are developed. The proposed multi-factor model demonstrates exceptional predictive capability (R2 = 0.9994), establishing a quantitative relationship between pore micro structure and mechanical performance. The innovative pore extraction method and mathematical modeling approach offer valuable insights into the micro-structural evolution mechanism of fiber concrete.

Mechanical and environmental performance of sugarcane Bagasse Ash from Khyber Pakhtunkhwa in sustainable concrete

In recent decades, the partial substitution of cement with sugarcane bagasse ash (SCBA) has received attention for construction applications because of its pozzolanic characteristics. However, regional-scale studies are encouraged to increase the use of SCBA at the industrial level. Limited literature is available on the effect of SCBA on concrete Alkali-silica reactivity (ASR), CO2 emissions and economic feasibility. In the current study, the influence of adding 0%, 5%, 10%, and 15% locally available SCBA from Khyber Pakhtunkhwa on the consistency, mechanical strength, ASR, N2 adsorption, mineralogy, microstructure, and elemental compositions of concrete was investigated. In addition, CO2 emissions and cost analysis were conducted for all the concrete mixes. Experimental findings revealed that consistency increased with the addition of SCBA percentages, whereas a delay in the setting time was recorded. The Compressive strength (CS) and split tensile strength for all SCBA-based mixtures increased with ageing, due to the finer particles and higher surface area of SCBA. Additionally, SCBA effectively reduces the expansion resulting from the alkali-silica reaction. The incorporation of SCBA significantly improved the microstructure with no sign of cracks, resulting in higher reactivity and the formation of additional CSH gel than the control mix. The findings confirmed that incorporating 10% of SCBA resulted in eco-friendly construction material with enhanced strength and cost savings. Furthermore, this study is beneficial to promote the use of locally available SCBA in concrete instead of disposal in landfills.

Impact of strain rate, free water, and aggregate fragmentation on the dynamic behavior of concrete in compression regime using a unique coupled DEM/CFD technique

This paper examines the simultaneous impact of strain rate, aggregate fragmentation, and free water on the dynamic behavior of concrete in mesoscale uniaxial compression conditions. A concrete specimen measuring 50 × 50 mm2 and having a low porosity of 5% was the subject of extensive two-dimensional (2D) dynamic investigations (that is, a research limitation). Its mesostructure was based on laboratory micro-CT images. Concrete’s fracture patterns, strength, brittleness, and fluid pressure distributions were all investigated. A mesoscopic pore-scale hydro-mechanical model based on a unique fully coupled DEM/CFD technique with breakable aggregate particles was utilized to study the behavior of partially or fully saturated concrete. A four-phase material comprising aggregate, mortar, ITZs, and macropores was used to replicate concrete. Groups of small spherical particles were used to simulate the fragmentation of aggregate particles with various shapes and sizes, allowing for intra-granular fracturing among them. A network of fluid channels was assumed in a continuous region between discrete elements. A two-phase laminar compressible fluid flow (air and water) in pores and cracks was suggested for wet concrete. The accurate volumes of pores and cracks were computed for tracking the liquid/gas content. Dynamic numerical compressive tests were performed with strain rates ranging between 1 1/s and 1000 1/s. Strain rate, aggregate fragmentation, and free water flow increased the dynamic compressive strength. Because of free water confinement in pores and cracks, the pore fluid pressures retarded a fracture process, enhancing the concrete dynamic strength.

Experimental evaluation of reinforced concrete columns produced with natural perlite aggregates under cyclic loading

Abstract A total of four reinforced concrete (RC) columns were tested to compare the structural capacities of RC columns produced by natural perlite aggregates and conventional concrete. The structural performance of the RC columns made from natural perlite aggregates was compared to conventional RC columns regarding the same concrete strength levels, sectional properties, and reinforcement layouts of conventional RC columns. The RC columns were tested under a combined constant axial load ratio of 30% with cyclic loading for two concrete strength levels, namely, 25 and 40 MPa. Load–displacement curves, energy absorption capacities, stiffness degradation, the moment‐curvature relationship, the plastic hinge mechanism, and the ductility index were experimentally obtained at two different concrete types along with the measured stress–strain properties of the conventional and perlite concrete. The test results showed that the construction of the RC columns using only perlite may become possible in the future by providing an adequate concrete stress–strain capacity, which will be improved. Additionally, the use of natural perlite aggregates can contribute to sustainable construction practices by reducing the reliance on conventional aggregates.

Incorporating Ground Granulated Blast Furnace Slag &amp; Fly Ash in Concrete Production for Sustainable Construction: A Review

Portland cement is the primary source of CO₂ emissions in concrete production due to the energy required for the calcination of limestone, the release of CO₂ from fuel combustion during cement manufacturing, and the hydration process during setting. To mitigate the environmental challenges associated with cement production, the use of industrial waste as cementitious material can significantly reduce both the volume of waste generated and its disposal in landfills, thereby freeing up land for other purposes. Concrete has traditionally incorporated natural pozzolans, waste and recycled materials, and industrial byproducts as partial replacements for Portland cement. Among these, Ground Granulated Blast Furnace Slag (GGBFS) and Fly Ash (FA) are the most commonly used supplementary cementitious materials (SCMs), known for enhancing the mechanical strength, flow ability, and durability of concrete. SCMs improve the concrete matrix's resistance to chemical attacks, reduce permeability, and contribute to long-term strength development. This review highlights the scientific literature on the feasibility and effectiveness of using GGBFS and FA as sustainable alternatives to cement in mortar and concrete production. GGBFS is a byproduct of the iron-making process, while FA is a fine particulate material generated from coal-fired power plants. The paper presents a detailed discussion of their manufacturing processes, physical characteristics, and their impact when used as partial cement replacements. It also summarizes findings from previous studies regarding optimal replacement percentages, which vary depending on the source, mix design, and particle size distribution of the materials. Finally, this review proposes process improvement strategies to optimize the use of GGBFS and FA in future sustainable concrete applications.

Estimation of compressive strength of ultra-high performance lightweight concrete (UHPLC) using neural network.

High strength and lightweight are key trends in concrete development. Achieving a balance between these properties to produce high structural efficiency (strength-to-weight ratio) concrete is challenging due to the complex relationship between compressive strength and material components. In this study, two artificial neural network (ANN) models-the BP and Elman networks were used to predict the compressive strength of ultra-high-performance lightweight concrete (UHPLC), based on a robust database of 115 test datasets from previous studies. The investigated parameters included the cement grade (Grade 42.5 and Grade 52.5), cement content (352 kg/m3-938 kg/m3), silica fume content (0 kg/m3-350 kg/m3), fly ash content (0 kg/m3-220 kg/m3), microsphere content (0 kg/m3-624 kg/m3), lightweight sand types (pottery sand, expanded perlite sand, and expanded shale lightweight sand), lightweight sand content (0 kg/m3-769 kg/m3), sand type (quartz sand, river sand), sand content (0 kg/m3-1314 kg/m3), water (90 kg/m3-395 kg/m3), water reduce (0 kg/m3-42.8 kg/m3), steel fiber content (0 kg/m3-234 kg/m3). Correlation analysis and sensitive analysis indicated that lightweight sand content and sand content had the most significant effects on UHPLC compressive strength, followed by water content. Conversely, fly ash content and lightweight sand type had minimal impact. The developed ANN models for UHPLC compressive strength demonstrated high predictive accuracy for both training and testing datasets, which the RMSE of BP network and Elman network were 0.226 and 0.160, respectively, while R2 of both two developed models were more than 0.98. Additionally, UHPLC exhibited a higher compressive strength-to-density ratio than high-strength concrete, ultra-high-performance concrete, and even Q235 steel. Three strategies were proposed for creating ultra-high-performance lightweight composites: optimizing packing density and lowering the water-binder ratio, along with careful selection of lightweight aggregates.

Time-dependent behavior of variable cross-section continuous box girder strengthened with external prestressing and web thickening

The time-dependent behavior of variable cross-section continuous box girder after strengthening is crucial for engineering post-evaluation. Firstly, the validity of the combined strengthening method utilizing external prestressing and web thickening was verified. The time-dependent behavior of the structure after combined strengthening was investigated by using ABAQUS software. The study examined the impacts of primary parameters on the time-dependent behavior, including the new concrete compressive strength, relative humidity, initial stress, thickness of web reinforcement and length of web reinforcement. Deflection versus time curves were got based on the confirmed finite element (FE) model. The longitudinal stress distributions were analyzed at the critical time points. The analysis revealed that because of the creep and shrinkage in reinforced regions, the deflection of the mid-span section was basically stable after one year of reinforcement, and the deflection was reduced by 6.5%. Simultaneously, the maximum compressive stress reserve at mid-span section decreased from −2.58 to −2.28 MPa, with a decrease of 11.63%. Finally, a simplified calculation method for predicting the long-term longitudinal strain of structure after strengthening was proposed, and the long-term performance could be better predicted. There was only a maximum error of −0.92% between the FE and calculation results.

Deformation Analysis of 50 m-Deep Cylindrical Retaining Shaft in Composite Strata

Cylindrical retaining structures are widely adopted in intercity railway tunnel engineering due to their exceptional load-bearing performance, no need for internal support, and efficient utilization of concrete compressive strength. Measured deformation data not only comprehensively reflect the influence of construction and hydrogeological conditions but also directly and clearly indicate the safety and stability status of structure. Therefore, based on two geometrically similar cylindrical shield tunnel shafts in Shenzhen, the surface deformation, structure deformation, and changes in groundwater outside the shafts during excavation were analyzed, and the deformation characteristics under the soil–rock composite stratum were summarized. Results indicate that the uneven distribution of surface surcharge and groundwater level are key factors causing differential deformations. The maximum horizontal deformation of the shafts wall is less than 0.05% of the current excavation depth (H), occurring primarily in two zones: from H − 20 m to H + 20 m and in the shallow 0–10 m range. Vertical deformations at the wall top are mostly within ±0.2% H. Localized groundwater leakage in joints may lead to groundwater redistribution and seepage-induced fine particle migration, exacerbating uneven deformations. Timely grouting when leakage occurs and selecting joints with superior waterproof sealing performance are essential measures to ensure effective sealing. Compared with general polygonal foundation pits, cylindrical retaining structures can achieve low environmental disturbances while possessing high structural stability.

Towards Selecting an Optimal Bonding Test Method for Rebar–Concrete: Comparison Between Pull-Out Test and Full-Beam Test

There are many methods for evaluating the bond behavior between rebar and concrete. For certain experimental purposes, selecting the ideal method for testing the rebar–concrete bonding properties is often a controversial problem. The most representative single-end pull-out test method and the full-beam test method were applied in this work to conduct bonding tests between rebar and concrete. Considering the influence of the concrete strength, bonding length, stirrup, and rebar slotting, these two testing strategies are compared and analyzed in terms of the specimen failure mode, bonding strength, bond–slip curve, and rebar stress distribution. Suggestions are offered regarding the selection of an appropriate method for evaluating the bond behavior between rebar and concrete based on an comparative analysis of the two tested approaches. The results presented herein provide a basis for the preparation of relevant test method standards.

Analysis of Mechanical Properties of Steel and Glass Fibre Concrete Compared to Standard Concrete: An Experimental Approach

This work investigates the use of steel and glass fibre as a to improve concrete mechanical qualities and to discovered that the use of fibre boosts concrete strength, particularly during early curing. Concrete constructions often fail due to cracks, which shorten their lifespan nowadays, additional chemicals or additives are utilized, such as steel and glass fibre. Concrete life is a major issue in the construction industry, with cracks causing issues the investigation of substitute reinforcing fibers to improve the mechanical qualities of concrete has been spurred by the rising demand for environmentally friendly building materials. In comparison to normal concrete, this experiment examines the performance of steel fiber-reinforced concrete (SFRC), glass fiber-reinforced concrete (GFRC), and a combination of steel and glass fiber concrete. Compressive, tensile, and flexural strengths were assessed through experimental investigation and glass fibers were added as an environmentally friendly substitute by 4% and 8% while steel fibers—known for their excellent tensile qualities—were also added at rates of 4%, and 8% by partial replacement of cement. According to the results, SFRC has better mechanical qualities and greatly increases tensile and flexural strengths. GFRC, on the other hand, showed promise as a long-lasting and reasonably priced reinforcement by exhibiting a moderate improvement in performance. This experimental data on the mechanical performance of steel and glass fibre-reinforced concrete under compression, tensile split, and flexure tests.

Determination of Material Properties for the Nonlinear Seismic Analysis of Reinforced Concrete Structures with ACI-318 and TS 500 Codes

ABSTRACT In this study, the effectiveness of two design codes is investigated by using experimental test results of two types of RC structures based on the nonlinear seismic responses. The Displacement-based Fiber Element Approach is used for numerical solutions. The material properties are established according to ACI-318 and TS 500 for concrete. The material properties of the cases which provide the best approximation to the experimental results are determined. The effectiveness of the equations suggested in the design codes to determine the elastic modulus and the tensile strength of concrete is investigated for the determined case.

Numerical simulation on residual axial compression bearing capacity of square in square CFDST columns after lateral impact

Square in square concrete-filled double-skin steel tube (CFDST) columns are widely preferred on account of their convenient nodal structural form and efficient construction process. In order to investigate the axial compression behavior of the columns after lateral impact, a precise numerical model for the post-impact axial compression of square in square CFDST columns was established using the finite element package, and was validated by existing experiments and studies. The residual axial compression bearing capacity of the columns after lateral impact has been analyzed. The typical vertical load–axial displacement curve, the failure mode and stress distribution of the columns have been studied. The parametric analysis has been also carried out to explore the influence of key parameters. Lastly, based on the parametric analysis, a simplified formula has been proposed to estimate the residual axial compression bearing capacity of the columns. The results show that under lateral impact, the columns generally exhibit a flexural failure mode. Local indentation occurs at the impact location, and buckling also appears at the bottom of the fixed support section. The coefficient of residual axial compression bearing capacity decreases with the increase of impact energy, slenderness ratio, and concrete strength, and increases significantly with the increase of steel strength.

Investigating the correlation between ultrasonic pulse velocity and compressive strength in polyurethane foam concrete

Using waste polyurethane foam as a partial replacement for natural coarse aggregates in concrete provides an eco-friendly solution by reducing waste and conserving natural resources. However, the strength behavior of polyurethane foam concrete differs from conventional concrete. To ensure effective design and quality control in the field, the viability of non-destructive testing methods for finding out the in situ mechanical properties of polyurethane foam concrete must be evaluated. This study establishes a correlation between compressive strength and ultrasonic pulse velocity (UPV) test to predict the compressive strength of polyurethane foam concrete using UPV test results. An experimental study was conducted on concrete specimens with varying percentages of polyurethane foam replacing natural coarse aggregate, ranging from 10 to 60% in 10% increments. The control concrete mix was 100% natural coarse aggregate without polyurethane foam. The properties of the specimens were evaluated after curing for 7, 14, and 28 days. It also examines polyurethane foam concrete workability, density, and microstructural properties. The findings show that the UPV and compressive strength of polyurethane foam concrete were lower than those of the control mix concrete for all replacement levels and curing ages. The empirical relationships between compressive strength and UPV were found to be exponential, with high correlation values ranging from 0.9012 to 0.9998. The predicted values and the experimentally measured results were compared in order to confirm the accuracy of the empirical equations for compressive strength prediction.

Optimized machine learning models for predicting ultra-high-performance concrete compressive strength: a hyperopt-based approach

Optimized machine learning models for predicting ultra-high-performance concrete compressive strength: a hyperopt-based approach

Experimental investigation on mechanical, durability, and microstructural sugarcane bagasse fiber reinforced concrete with partial replacement of cement by corn waste ash

The expensive cost of cement and environmental pollution resulted in its production can be decreased by using partially cement replacing materials like corn waste ash (CWA). CWA (a blend of Corncob ash and Cornhusks ash) have been found to contribute to the better improvement of concrete properties such as high strength, durability, thermal conductivity and insulating properties. In addition, concrete cracks and issues of strength can solved using fibrous materials. Sugarcane bagasse fiber (SCBF) also has a great effect on microstructure of concrete mix since it allows a homogeneous distribution of the cement paste. In this study, the effect of CWA and SCBF on concrete strength, durability and microstructure was investigated. Concrete composite with 1% SCBF gains strength within the acceptable strength limit, which is required to attain 65% of the strength gained at 28 days. An optimum of 1% SCBF was used to reinforce concrete. The split tensile strength of SCBF reinforced concrete increased with CWA blend increment up to CWA of 7.5% cement replacement, then it decreased. The compressive strength of SCBF reinforced concrete decreased with CWA blend increment. The least water absorption and the highest resistance to chemical attack (H2SO4 and NaOH) of SCBF-reinforced concrete were observed with a CWA of 7.5% blend. However, for further addition of CWA, water absorption and weight loss due to chemical attack increases. After 28 days of % sulfuric acid curing, the optimum compressive strength was found with a CWA of 2.5% blend. The microstructure of SCBF reinforced with CWA of 2.5% blend shows very compacted with negligible pores and cracks due to the filler effect of CWA and its pozzolanic reaction.