Representing the cost reduction of concrete containing clay brick powder and waste tyre rubber from the performance reference

Abstract

Under the effects of waste materials, non-conventional concrete mixes usually exhibit reduced costs, because of the use of waste materials compared with conventional concrete materials. On the other hand, the criteria for reducing the concrete cost should simultaneously incorporate the concrete performance. However, balancing the cost and performance of concrete incorporating waste tyre rubber (WTR) and clay brick powder (CBP) is still unclear. This study establishes a simple yet representative correlation between concrete cost and performance to illustrate the applications of modified concrete mixes containing CBP and WTR for sustainable construction. The study uses experimental works of compressive, split tensile and flexural strengths to assess the performance of concrete containing CBP and WTR. This information is exploited to determine concrete mixes capable of reducing cost at considerable concrete performance. The results highlight that the contributions of CBP and WTR to reductions of concrete cost cannot be neglected, particularly when high contents of these waste materials are used. Considerable relationships between costs and mechanical properties are validated using several examples, including the coefficients of determination of more than 0.65. While the inclusion of WTR addresses the issue of cost reduction in concrete, it falls short in improving the performance of concrete. It is demonstrated that the 5P0T concrete mix (5 % CBP and 0 % WTR) offers reasonable concrete performance and plausible cost reduction for use in sustainable construction. Moreover, the results provide theoretical and technical support on the contents of CBP and WTR that can achieve cost-performance balance. Therefore, the correlations between the cost and performance of the concrete presented here can be crucial in generating new non-conventional concrete mixes for sustainable construction.