• Inclusion of WTR and WBP is proposed to reduce concrete energy requirement • Inclusion of WBP and WTR promotes sustainable construction • Response surface methodology shows distinct energy requirement reduction of concrete incorporating WBP and WTR. • WBP is more sensitive to energy requirement than WTR. The energy requirement reduction in concrete using waste materials, viewed as a strategy for sustainable construction, requires evaluation among many concrete grades. Waste materials such as waste brick powder (WBP) and waste tyre rubber (WTR) have been receiving an increasing interest due to their abilities to satisfy both sustainability and performance requirements simultaneously. However, the specific impact of these materials on energy demand across different concrete strength classes remains underexplored. This study evaluates the energy requirement reductions of classes 50, 55 and 60 concrete mixes containing WBP and WTR. Response surface methodology was also employed to understand the relationships between input variables (WBP and WTR) and desired outcome (energy requirement). The results highlight that using WTR and WBP in concrete significantly reduces the energy requirements of high-strength concrete mixes. Remarkably, the inclusion of 5% WBP causes higher energy requirement reductions (>4.5% reductions) in contrast with 20% WTR (<0.82% reductions). The response surface methodology results show that WBP inclusion in concrete is more sensitive to energy requirement compared with WTR. However, their combined influence on energy requirements depends on their contents and their basic unit values among the various concrete classes. Moreover, the current results strongly suggest that smaller replacement levels of WTR and WBP are key factors towards sustainable construction and considerable concrete performance even though the research does not include detailed experimental works on concrete properties. This research provides new insights into the developing non-conventional concrete mixes using WTR and WBP for sustainable construction.
Sinkhonde et al. (Thu,) studied this question.