Recycled Coarse Aggregate Research Articles

The effect of water absorption distribution of recycled coarse aggregate on the compressive strength distribution of high-performance concrete

High water absorption is a typical characteristic of recycled coarse aggregate and is often used to explain the loss of performance of concrete when replacing natural coarse aggregate with recycled coarse aggregate. Extensive attention has been paid to the mean value of the water absorption of recycled coarse aggregate, but not to the standard deviation. This paper aims to assess whether recycled coarse aggregates with the same mean water absorption but different standard deviations will perform equally in high-performance concrete (HPC). The resulting HPC mixtures exhibited very similar compressive strength. Even so, it was hypothesised that as the standard deviation of the water absorption of recycled coarse aggregate increases over a wide range, the compressive strength of HPC will first increase due to local variations in the water/cement ratio, then decrease due to the presence of weak particles, and finally remain constant due to the role of the surrounding new mortar.

A Study on the Flexural Performance of Para-aramid Fiber Reinforced Concrete Beams with Recycled Coarse Aggregates

This study aims to investigate the effectiveness of para-aramid fiber sheet in enhancing the flexural performance of reinforced concrete (RC) beams made with Environmental-Friendly Recycled Coarse Aggregates. The experimental program examines the effect of substitution ratio of recycled aggregates (0%, 30%, and 50%), type of para-aramid fiber sheet (KN 206 RFL and KN AA070-RFL), and the method of fiber sheet attachment (bottom and bottom-side). The test results show that the ultimate load-carrying capacity of RC beams reinforced with para-aramid fiber sheet attached to the bottom and side parts increased by 23.9% compared to the unreinforced specimens. The main findings of the study include the identification of the BU-type attachment method as the most effective method for enhancing the flexural performance of reinforced concrete beams. The comparison of the experimental results with analytical predictions showed that the nominal flexural strength obtained from the experimental study was lower than the analytical predictions, but the ductile capacity of the specimens indicated the effectiveness of para-aramid fiber sheet reinforcement in EFRCA RC beams for flexural strength. The study highlights the potential of using para-aramid fiber sheet in improving the flexural behavior of RC beams made with recycled aggregates, offering a sustainable solution for the construction industry.

An Evaluative Review of Recycled Waste Material Utilization in High-Performance Concrete

The disposal of waste materials and their adverse effects on the environment have become a worldwide concern, disturbing the fragile ecological equilibrium. With growing awareness of sustainability in the construction industry, it is of great importance to recycle waste materials for producing high-performance concrete (HPC). This aligns with the twelfth Sustainable Development Goal (SDG) of the United Nations, emphasizing responsible production and consumption, especially concerning the production of HPC using waste materials and energy-efficient methods. The review evaluates the purposeful utilization of recycled waste materials to improve the engineering characteristics of HPC, taking into consideration pertinent literature. It encompasses a comparative evaluation of strength development, water absorption, microstructures, and x-ray diffraction (XRD) analyses of HPC manufactured with different types of recycled waste materials. The key result of the review showed that using incinerated bottom ash (IBA) below 25% and incorporating 40% copper slag can enhance HPC’s mechanical performance. Additionally, recycled coarse aggregate (RCA) can replace up to 50% of conventional aggregate in self-compacting HPC with minimal impact on durability properties. In HPC cement substitution research, fly ash, silica fume, and metakaolin are prominent due to their availability, with fly ash showing remarkable durability when used as a 15% cement replacement. This thorough review offers valuable insights for optimizing the utilization of recycled waste materials in the development of environmentally friendly HPC. Doi: 10.28991/CEJ-2023-09-11-020 Full Text: PDF

Cyclic loading tests and seismic behaviors of steel-reinforced recycled aggregate concrete filled square steel tube composite columns

To investigate the seismic performance of steel-reinforced recycled aggregate concrete (RAC) filled square steel tube composite columns, the cyclic load tests were conducted for nine columns. The effects of steel ratio of profile steel, width thickness ratio of square steel tube, the replacement rate of recycled coarse aggregate (RCA) and axial compression ratio on the seismic performance of composite columns were investigated in detail. The failure characteristics, hysteretic curves, performance indexes and stress-strain distribution of columns were analyzed in detail. The results show that an obvious plastic hinge is generated at the column base and present a compression-bending failure mode. The hysteretic curves of columns present a full shuttle shape, showing that the columns have good energy dissipation capacity and ductility. The use of RCA has little impact on the seismic performance of composite columns. In particular, the bearing capacity of columns with fully RCA is only 1.57% lower than that of ordinary concrete columns. With the increase of profile steel ratio or the decrease of width thickness ratio of square steel tube, the ductility and energy dissipation capacity of columns obviously improve. Increasing the axial compression ratio is conducive to improving the bearing capacity of columns to some extent, but not conducive to improving the energy dissipation and deformation capacity of columns. Based on the failure mechanism of composite columns, combined with AISC specification, the modified formula on the horizontal bearing capacity of steel-reinforced RAC filled square steel tube composite columns is proposed, which is well verified by the test results.

HIGH QUALITY ECONOMICAL CONCRETE WITH VARYING COMPOSITIONS OF RECYCLED AGGREGATE AS A SUBSTITUTION OF COARSE AGGREGATE

The high level of infrastructure development at present forces old buildings to undergo repairs or even demolition to make way for new buildings that are more suitable and representative. The resulting demolition waste is usually discarded, becoming solid waste. The solution to the above problem is recycling the concrete waste as an alternative aggregate to replace some or all of the natural aggregates in the concrete mixture. Concrete with recycled aggregates is made with several composition variations of replacement to natural coarse aggregates, which is 0%, 25%, 35%, 45%, and 50%. The concrete will be tested for compressive strength at 28 days from the concrete mixture preparation. The research results showed that the highest compressive strength was found in the variation with a 25% replacement of natural coarse aggregates, which was 50.1 MPa, and the optimum compressive strength value is obtained at the variation of 23.51% recycled coarse aggregate substitution. Keywords: Recycled Aggregate; Innovation; Eco-Green Concrete; Concrete Compressive Strength; Sikament NN.

Influence of mixed recycled coarse aggregate on the engineering properties of recycled aggregate concrete

Influence of mixed recycled coarse aggregate on the engineering properties of recycled aggregate concrete

Effect of carbonated recycled coarse aggregates on the mechanical properties of 3D printed recycled concrete

A modification method of carbonation combined with presoaking in nano-SiO2 solution was employed to enhance the recycled coarse aggregates (RCA). The water absorption, apparent density and crushing index of RCA before and after carbonation were tested. The water absorption, compressive strength, flexural strength and splitting tensile strength of 3D printed recycled aggregate concrete (3DPRAC) with different RCA replacement rates were further investigated. Microscopic tests including X-ray diffraction and scanning electron microscopy were performed to analyze the changes in phase composition and microstructure of RCA, while X-ray computed tomography was utilized to explore the pore defect evolution of 3DPRAC. The results demonstrated the method of carbonation combined with presoaking in nano-SiO2 solution significantly improved the physical characteristics of RCA and densified the microstructure of 3DPRAC. With an increase in RCA replacement rate, there was a decrease in the mechanical properties in all directions. At the RCA replacement rate of 100 %, the compressive strength, flexural strength and splitting tensile strength increased by a maximum of 24.71 % in the X direction, 12.95 % in the Y direction and 18.27 % in the Z direction after RCA carbonation, respectively. The pore defects of 3DPRAC were effectively optimized by the inclusion of carbonated RCA. The modification mechanism was explained based on the enhanced performance of RCA and pore defect evolution.

Axial Compression Behavior of Composite Sandwich Panel with Mixed Recycled Coarse Aggregate Concrete

The coarse aggregate produced from the construction and demolished waste of masonry structure is called mixed recycled coarse aggregate (MRA), which is mainly composed of concrete recycled coarse aggregate (CRA) and brick recycled coarse aggregate (BRA). The paper presents the results of an experimental and numerical study of concrete composite sandwich panel made with MRA. The composite sandwich panel with MRA (CSPMRA) were tested under axial compression to investigate the influence of concrete mix proportion, thickness of insulation board and added edge frame on the load-displacement curve, load-strain curve, vertical displacement, ultimate bearing capacity and failure mode of CSPMRA. Results of the experimental and finite element analysis (FEA) were compared with the results based on Chinese code, ACI design equation and other empirical equations developed by researchers which might be applicable to predict the ultimate load of sandwich panels. A semi-empirical equation was proposed to better fit the experimental and the FEA results.

Performance of concrete containing pristine graphene-treated recycled concrete aggregates

Upcycling recycled coarse aggregates (RCAs) in concrete is a promising way to decrease the environmental effect of construction and demolition waste and improve concrete sustainability. Pretreatment of RCAs helps to enhance the quality of the resulting concrete and results in an increased level of confidence for material suppliers to systematically use RCAs to replace virgin aggregates for concrete production. This study demonstrates the utilization of pristine graphene for pretreating RCAs with the aim of effectively alleviating the loss of mechanical and durability performance of concretes when compared to virgin aggregate concretes. The RCAs were presoaked in water solution containing graphene concentration ranging from 0 to 0.5 %. Then, 50 % of natural coarse aggregates were replaced with the RCAs for concrete production. Different properties of concrete including slump, axial compression, splitting tension, water absorption and drying shrinkage were measured. In addition, microanalysis of the aggregates was performed by x-ray diffraction analysis (XRD) and scanning electron microscopy (SEM). Based on results, treating the RCAs with 0.2 wt% pristine graphene results in increased workability (13 %), compressive strength (21 %) and tensile strength (12 %) and decreased water absorption (22 %) and drying shrinkage (20 %) of the RCA concrete. Increasing the concentration of the graphene beyond 0.2 wt% is found to decrease the workability and strength properties and increase the water absorption and drying shrinkage. This is attributed to the agglomeration of the graphene at high concentrations, leading to non-uniform filling effects and ineffective microcrack and void filling. It is also found that 0.2 wt% is the optimum pristine graphene concentration, which can lead to an RCA concrete with similar mechanical and durability properties to the conventional concrete.

Performance of recycled aggregate concrete (RAC)-filled steel tubular (FST) members and K-joints under lateral impact

A series of tests are conducted on 26 recycle aggregate concrete (RAC)-filled steel tubular (FST) members and 25 RAC-FST K-joints on a drop hammer rig. Salient parameters considered in the experimental program include the axial load ratio, the replacement ratio of recycled coarse aggregate (RCA), the height of the hammer and the application of combined corrosion and sustained loading, et al. The shrinkage and creep deformation of core RAC is measured for 185 days, and the influence of key parameters on the structural performance of both RAC-FST members and K-joints are analyzed. A finite element (FE) model is established and verified against the test results. Considering the effects of combined chloride corrosion and sustained loading, the FE model is successively employed to investigate the behaviour of RAC-FST members and K-joints under lateral impact, including the failure mode, the time history relationships of impact load and deflection, the distribution of internal force and stress, et al. The axial compression performance of the member and the chords of K-joints after being subjected to combined loading is evaluated. On the basis of the parametric analysis, simplified models considering the effects of chloride corrosion and sustained loading are obtained to calculate the dynamic flexural capacity of the RAC-FST members and the chords of RAC-FST K-joints under impact loads.

The Structural Behavior of Reinforced Concrete Beams Made with Locally Produced Recycled Aggregate in the UAE

In this study, the feasibility of utilizing locally produced coarse recycled aggregate (RA) from demolition waste in the UAE for structural applications was investigated. A comprehensive literature review on the subject showed that the shear and flexural responses of reinforced beams utilizing aggregate from concrete demolition waste are greatly dependent on the aggregate replacement ratio and the quality of the recycled aggregate. The experimental program in this study consisted of three phases. Phase I focused on the evaluation of the physical and mechanical characteristics of the RA, Phase II addressed the mix design and fresh and hard properties of the concrete, and Phase III dealt with the flexural and shear behavior of structural members. The research involved twelve 150 mm × 300 mm reinforced concrete beams with a length of 1500 mm or 2000 mm that were made with 0% (control), 50%, or 100% recycled coarse aggregate, replacing natural coarse aggregate (NA). Two target concrete compressive strengths, 25 and 35 MPa, were considered in the investigation. The results showed that the recycled aggregates had lower crushing and LA abrasion values by 40% and 18–28%, respectively, whereas the absorption capacity was 40–300% higher compared to the natural aggregate. In addition, the mechanical properties of the concrete made with different replacement ratios (R%) of RA were either similar or slightly less than those of the control mix. The shear beam tests with fc′ = 25 MPa showed that the 50%- and 100%-replacement-ratio beams demonstrated closely matched normalized shear strength values that exceeded their corresponding NA beam by 12.5%, while the shear beam tests with fc′ = 35 MPa showed that the NA beam exhibited normalized shear strength surpassing the 50% RA and 100% RA beams by 12.5% and 17.5%, respectively. In the flexural beam tests, the flexural strength exhibited minimal disparities for the beams that shared the same RA% but differed in their compressive strength targets, and overall, the variation in the RA% had a marginal impact on the flexural strength of the beams. Further, an increase in the RA% corresponded to an increase in the shear ductility index, which was in contrast with the findings on the flexural ductility index. Furthermore, predictions of flexural strength using the ACI318-19 code and shear strength using the strut-and-tie model yielded comparable results to the experimental ones.

Mechanical Properties of Steel-Polyvinyl Alcohol Fiber Recycled Coarse Aggregate Self-Compacting Concrete: Orthogonal Testing

Mechanical Properties of Steel-Polyvinyl Alcohol Fiber Recycled Coarse Aggregate Self-Compacting Concrete: Orthogonal Testing

One-part eco-friendly alkali-activated concrete – An innovative sustainable alternative

The primary objective of this study is to develop an eco-friendly one-part alkali-activated concrete (OPAAC) by incorporating a combination of fly ash (FA), ground granulated blast furnace slag (GGBS), and micro silica (MS). In this investigation, the proportion of MS is maintained at 20% of FA, while the maximum replacement of FA with GGBS is set to 60%, varying in 20% intervals (i.e., 0%, 20%, 40%, and 60%). Further, the natural aggregates (NA) are substituted with recycled coarse aggregates (RCAs), ferrochrome slag aggregates (FCSAs), or a combination of both. The influence of GGBS and alternative aggregates (RCAs, FCSAs) on the mechanical properties of OPAAC is thoroughly examined. To provide a comprehensive assessment, the properties of OPAAC are compared against Ordinary Portland Cement (OPC) concrete (CC) of equivalent grades. Additionally, microstructural and mineralogical investigations are conducted to determine the formation of distinct hydration products, utilizing scanning electron microscopy (SEM) and X-ray diffractometry (XRD) techniques. In OPAAC containing FA, the primary hydration products identified are alkaline alumino silicate hydrates (CASH and NASH). As the GGBS content increases, calcium silicate hydrate (CSH) becomes the predominant hydration product. Furthermore, in order to assess the sustainability of OPAAC, an analysis of embodied CO2 emissions is performed, and the results are compared with CC and alkali-activated concrete. Notably, OPAAC comprising 40% FA replaced with GGBS, 50% RCAs, and 50% FCSAs demonstrates the most favourable mechanical properties and exhibits lower CO2 emissions.

Study on axial compressive behavior and stress–strain relationship of fiber-reinforced alkali-slag recycled concrete

Fiber-reinforced alkali-slag recycled concrete, a novel green building material with high-efficiency solid-waste utilization, can effectively utilize waste slag and recover coarse aggregates. However, no relevant research has been conducted on the mechanical properties under axial compression. Therefore, this study investigated the influence of fiber type, fiber content, and recycled coarse aggregate content on the axial compression mechanical properties of fiber-reinforced alkali-slag recycled concrete. The results show that an appropriate amount of steel, basalt, and polypropylene fibers can effectively improve the axial compressive strength, peak compressive strain, and elastic modulus of alkali-activated slag recycled concrete. The axial compressive strength, peak compressive strain, and elasticity can be enhanced by 10.6–31.9%, 26.0–29.3%, and 1.4–69.1%, respectively. Basalt fibers had the worst effect, while steel fibers had the best effect. A small proportion of recycled coarse aggregate can slightly increase the axial compressive strength and peak compressive strain while significantly reducing the elastic modulus. An axial compression stress–strain model of the fiber-reinforced alkali-slag recycled concrete was established. These results provide basic theoretical support for the comprehensive and effective exploitation of waste slag and building waste.

Orthogonal experimental design for compressive strength of recycled coarse aggregate concrete with silica fume-slag-fly ash hybrid micro-powders

Recycled Coarse Aggregate Concrete (RAC) is a type of concrete that uses recycled coarse aggregate (RCA) instead of natural coarse aggregate (NCA), which helps to reduce the negative environmental impact of construction waste. In order to improve the low compressive strength of RAC and solve the problem of shortage of natural aggregates, this paper develops a high-performance concrete called recycled coarse aggregate concrete with silica fume-slag-fly ash hybrid micro-powders (HMRAC) by replacing part of the cement with a mixture of micronized silica fume (SF), slag (SG) and fly ash (FA) and using RCA of 50% mass instead of NCA. The optimum combination parameters and prediction model for the compressive strength of HMRAC were also proposed by orthogonal experimental design. A constant water-cement ratio of 0.45 and a 50% mass replacement of natural coarse aggregate (NCA) by recycled coarse aggregate (RCA) were adopted in the experiment, and the mass replacement ratios of silica fume (SF), slag (SG), and fly ash (FA) for ordinary Portland cement (OPC) were used as the test variables. In total, 16 combinations were tested, including a control group where 50% of the NCA mass was replaced by RCA. First, we investigated the degree and significance of the effect of the mass substitution ratio of SF, SG, and FA on the compressive strength of HMRAC using analysis of variance (ANOVA) and extreme difference analysis. Then, we determined the optimal combination ratio of SF, SG, and FA. Secondly, multiple regression analysis was used to propose a multiple regression model for predicting the compressive strength of HMRAC. Finally, we computed and analyzed the carbon emissions of HMRAC. The results indicated that the mass substitution rates of FA and SG had a greater effect on the compressive strength, and the mass substitution rate of SF had a lesser effect on the compressive strength. The interaction of SF, SG, and FA can significantly enhance the compressive strength of RAC. The optimal compressive strength performance of HMRAC was observed when the proportions were as follows: SF constituted 10%, SG made up 15%, and FA accounted for 5%. The regression model has reasonable accuracy and a small standard deviation of residuals. It can effectively predict the compressive strength value of HMRAC, aligning well with the experimental results. It exhibits a superior carbon reduction rate of 21.90%, compared to conventional concrete.

Analysis on rheological and workability properties of steel-polypropylene fibers reinforced self-compacting concrete with recycled coarse and fine aggregates

Rheological and workability properties are important for the design of steel-polypropylene fibers reinforced recycled aggregates self-compacting concrete (SPFRA-SCC). In this work, the rheological and workability behavior of SPFRA-SCC was investigated to provide guideline for structural application. The SPFRA-SCC mixtures were prepared with various combined replacement contents of recycled coarse aggregate (RCA) and recycled fine aggregate (RFA). Meanwhile, the influences of steel-polypropylene fibers (milling steel fiber and polypropylene fiber) with different combined volume fractions, silica fume and fly ash on the rheological and workability properties of SPFRA-SCC were also studied. Modified-Bingham and Herschel-Bulkley models were employed to describe the rheological behavior of SPFRA-SCC. Based on the experimental results, the multi-output least-squares support vector regressor (MLS-SVR) method was adapted to predict the rheological parameters of SPFRA-SCC. Test results showed that RCA, RFA, and hybrid steel-polypropylene fibers had a negative effect on the workability and rheological properties of SPFRA-SCC, while appropriate content of silica fume and fly ash could ameliorate the rheological and workability parameters. Both Modified-Bingham and Herschel-Bulkley models could characterize the shear thickening behavior of SPFRA-SCC, and MLS-SVR method could be well applicable to predicate a close estimation of rheological parameters based on the experimental results.

Study on Mechanical Properties and Erosion Resistance of Self-Compacting Concrete with Different Replacement Rates of Recycled Coarse Aggregates under Dry and Wet Cycles

Concrete that self-compacts is frequently utilized in engineering construction. Recycled coarse aggregate self-compacting concrete (RCASCC) is made by partially substituting recycled coarse aggregates (RCA) for natural coarse aggregates in order to conserve construction resources. This study examines the impact of linked sulfate erosion, dry and wet cycles, and RCA replacement rates of 0%, 25%, 50%, 75%, and 100% on the mechanical properties and durability of RCASCC. By using the mass loss rate, relative dynamic elastic modulus, corrosion resistance factor, X-ray diffraction (XRD), scanning electron microscope (SEM), and atomic force microscope (AFM) analyses, as well as other macroscopic and microscopic methods, it is possible to examine the deterioration patterns of RCASCC under dry and wet cycles. The results demonstrate that the addition of RCA has a notable impact on concrete’s resistance to sulfate attack during both dry and wet cycles. The erosion products steadily rise, the interfacial transition zone (ITZ) becomes rougher, and the sulfate resistance falls as the replacement rate of RCA rises. According to the findings of SiO2, AFt, and CaCO3, the examination of corrosion products from XRD and microstructure from SEM and EDS is carried out. The old mortar that has adhered to the surface of RCA, as shown by the AFM analysis of ITZ and the SEM analysis of RCA, can significantly affect the roughness of ITZ inside RCASCC.

Microbial Technique to Treat Recycled Aggregates from Construction Waste for its Effective reutilization in Concrete

<p>Excessive consumption of natural resources for concrete production results in the diminution of conventional resources, leading to the scarcity of construction materials. Perhaps, the dumping of construction wastes increases the municipal wastes ensuing in disposal problems. The dumped construction wastes act as a hazard and disturb the integrity of the environment. Nevertheless, the requirement for aggregates in the construction sector increases, hastily alarming the researchers in their search of sustainable alternative materials. The recycling of construction waste to produce recycled coarse aggregate (RCA) as a suitable alternative to natural coarse aggregates (NCA) conserves natural resources and promotes sustainability in construction. However, the quality of recycled coarse aggregate was inferior compared to natural coarse aggregates due to the adherence of mortar. This paper investigates the sustainable use of Bacillus subtilis with different concentrations to enhance the quality of RCA. The concrete mixes manufactured with optimized BRCA were tested for their mechanical and durability properties. It could be observed that the strength of BRAC was enhanced by 12.63% relative to NAC, and the durability properties such as water absorption, chloride penetration and carbonation of BRAC were reduced by 18.53%, 16.52% and 20% relative to RAC. Microstructural studies through SEM and XRD revealed the deposition of CaCO3 on the micro-pores of RCA, and that improves the properties of the concrete.</p>

Effects of Recycled Concrete on Structural Behavior of Composite Beams with Y-Rib Shear Connectors

This study inspects the structural behavior of composite steel concrete beams connected together by Y-Rib shear connectors using recycled concrete. The main method involves using stud shear connectors with normal concrete. By comparing the structural performance of Y-Rib shear connectors with conventional stud shear connectors, the study aims to determine the benefit of using this type of connector with recycled concrete. Improved results in terms of maximum load-bearing capacity before failure and maintaining structural integrity until failure would indicate a viable solution to the sliding issue seen in traditional composite beams. Regardless of challenges in acquiring traditional shear connectors, the study also explores an alternative: 20mm diameter reinforcing bars. Although this falls outside the primary research scope, the main focus remains on the behavior of composite beams connected by Y-shaped shear connectors with recycled concrete. The investigation encompasses 18 shear connector types, divided into two groups: 9 models with normal coarse aggregate concrete (35.17 MPa) and 9 models with recycled coarse aggregate concrete (33.48 MPa) to determine the benefit of recycled aggregate concrete usage.

Machine learning approach for investigating compressive strength of self-compacting concrete containing supplementary cementitious materials and recycled aggregate

Supplementary cementitious materials (SCMs) and recycled coarse aggregate (RCA) have the potential for sustainable development and resource utilization and have been widely applied in self-compacting concrete (SCC). However, traditional experiment approaches for predicting its compressive strength suffer from inefficiency, time-consuming, and high cost. To address these issues, machine learning (ML) models are employed, evaluated, and compared in this paper. First, a database of 337 samples with 10 features is collected and established. Then, the 12 ML models, including SVM, KNN, DT, RF, ANN, GBoost, XGBoost, AdaBoost, CatBoost, LightGBM, HistGBM, and GEP are applied for modeling to predict the compressive strength. Finally, both feature importance, individual conditional expectation, and partial dependence plot are utilized to assess the importance and the effect of each and coupled parameters. The results show that the CatBoost and LightGBM models generally possess superior performance in various aspects, including higher R2 values, lower RMSE, MSE, and MAE values, as well as smaller errors. Among the Boosting models, except for the AdaBoost model, satisfactory predictive ability is observed. The ANN and RF models also demonstrate relatively good performance, and the SVM, DT, KNN, and GEP models present relatively poorer performance. Curing age and W/CMs exhibit the most pivotal features on model prediction. Furthermore, RCA replacement ratio plays a more prominent role than CA, and SCMs contribute somewhat to the compressive strength of concrete, but not as much compared to cement. Also, it is important to acknowledge the significant contribution of SP. This study offers a systematic evaluation of the prediction of compressive strength in SCC containing SCMs and RCA, making a notable contribution to both the existing literature and practical applications.