Optimization of sustainable concrete incorporating coarse recycled aggregate using a customized single-factor response surface methodology (CSFRSM) approach

Abstract

This study systematically optimizes the coarse recycled aggregate (RA) content in concrete using a customized Single-Factor Response Surface Methodology (CSFRSM). It focuses exclusively on coarse recycled aggregate content as the sole variable to comprehensively evaluate its effects on compressive strength, flexural strength, splitting tensile strength, and workability. A Python-based correlation analysis was integrated to reveal interdependencies among concrete properties and enhance the optimization process. The results demonstrate that increasing RA content from 0 to 50% reduces compressive strength (41.35–28.41 MPa), flexural strength (5.26–4.10 MPa), and splitting tensile strength (3.58–3.36 MPa). The optimal mix was achieved at 27.5% RA replacement, yielding a slump value of 26.90 mm, flexural strength of 4.73 MPa, splitting tensile strength of 3.51 MPa, and compressive strengths of 25.85 MPa at 7 days and 35.10 MPa at 28 days. The findings highlight that CSFRSM provides a robust framework for optimizing concrete properties, supporting the advancement of sustainable construction practices.