Advancing low-carbon concrete: performance assessment and optimization of glass powder, biomass fly ash, and shredded rubber in concrete mixtures

Abstract

The production of conventional concrete has a substantial negative impact on the environment, underscoring the need for effective strategies to lessen this impact. One promising approach is the partial replacement of cement and/or aggregates with waste materials, which enhances the sustainability of concrete. This method reduces the volume of waste sent to landfills while also conserving natural resources and lowering environmental risks. Among various waste materials, glass powder (GP) and biomass fly ash (BFA) have shown promise as partial cement replacements, while shredded rubber (SR) can be used as a substitute for fine and coarse aggregates. However, designing concrete with such materials poses challenges in achieving the required mechanical and durability performance standards. This study aims to develop optimal mix designs incorporating SR, BFA, and GP to meet environmental, durability, workability, and mechanical performance requirements. Durability was assessed using tests such as freeze–thaw resistance test, rapid chloride migration (RCMT), rapid chloride penetration (RCPT), and surface/bulk electrical resistivity. The Global Warming Potential (GWP) and predicted service life were also evaluated to assess environmental impacts. In addition, the mechanical behavior of the developed mixes was studied using compressive strength (CS), splitting tensile strength (STS), and modulus of rupture (MOR). Response Surface Methodology (RSM) was used to model and optimize the mix variables, followed by the development of a meta-model enhanced by Monte Carlo back analysis to improve prediction accuracy and identify the target mix design. Large-scale reinforced beams were cast to evaluate the structural performance of the optimized mixes. The results demonstrate that GP not only improves concrete properties but also mitigates the negative effects of BFA and SR. Overall, the optimized use of GP, BFA, and SR effectively reduces cement content and carbon emissions while satisfying structural, durability, environmental, workability, and mechanical criteria.