Statistical evaluation of fresh properties of self-compacting concrete incorporating construction and industrial waste: a sustainable approach.

This study investigates the fresh properties of self-compacting concrete (SCC) developed using recycled concrete aggregates (RCA) as coarse aggregate replacement and ground granulated blast-furnace slag (GGBS) as cement replacement. This study employs an integrated statistical framework to simultaneously analyze, interpret, and optimize multiple SCC fresh performance parameters. SCC mixes were prepared with 15% to 45% GGBS and 20% to 100% RCA, and their fresh properties were evaluated through slump flow, T500, J-ring, V-funnel, L-box, and U-box tests. Microstructural and chemical characterization of the raw materials was conducted using scanning electron microscopy (SEM) and X-ray fluorescence (XRF) to assess morphology and compositional compatibility before evaluating the fresh properties of SCC. Results showed that workability decreased with increasing RCA but improved with GGBS by up to 30% due to enhanced paste volume and reduced internal friction. Regression analyses revealed strong correlations between key fresh property parameters, such as slump flow and T500 (R2 = 0.971), J-ring and V-funnel (R2 = 0.880), and L-box and U-box (R2 = 0.947). A two-way ANOVA confirmed that GGBS and RCA have a statistically significant effect on fresh properties (p < 0.001). Furthermore, response surface methodology (RSM) to identify optimal mix proportions and principal component analysis (PCA) to explore the underlying structure of the test methods were also performed. The results indicate that a mix with 30% GGBS and 60% RCA provides optimal fresh properties, confirmed by PCA and regression analyses. These findings provide a practical framework for designing sustainable SCC mixtures using construction and industrial waste materials, enabling engineers to balance workability, passing ability, and sustainability requirements in real-world construction applications.