Energy assessments of concrete incorporating waste tire rubber and waste brick powder: A comparative analysis of various concrete grades

Some non-conventional concrete mixes are a new generation of concrete characterised by reduced energy requirements during their production. Compared with conventional concrete, some non-conventional concrete mixes incorporating waste materials have reduced energy requirements due to their excellent abilities in constraining high energy requirement values of conventional concrete ingredients. Despite several studies on energy requirement of non-conventional concrete, the underlying reduction of energy requirement of concrete containing waste tire rubber (WTR) and waste brick powder (WBP) is not completely understood due to the absence of appropriate studies in this area. In this study, the energy requirements of control and non-conventional concrete mixes among various concrete grades (20 MPa, 25 MPa and 30 MPa) are developed in conjunction with the compressive strength results of concrete, to generate eco-concrete mixes with reduced energy requirements and considerable strength performances. The results indicate that inclusion of WTR and WBP in concrete reduces the energy consumption of concrete. It is shown that the choice of amounts of WTR and WBP in concrete should not only be based on the drive to reduce energy consumption, but also the motivation to avoid substantial reduction in concrete compressive strength. For all concrete grades, the reductions in compressive strength of 5P20T mixes (5 % WBP and 20 % WTR) need to be greater than 32.57 % compared with 0P0T mixes, to achieve concrete energy requirement reductions of less than 5.56 %. Moreover, the reductions in energy requirements of concrete for 5P10T mixes are nearly 5 % for all concrete grades, with reductions in compressive strength being in the range of 11.67 % – 16.87 %. The study establishes that 5P10T concrete mixes provide a route for reductions in energy requirement of concrete without substantial reductions in compressive strength. These results therefore imply the exciting possibility that the energy requirement of concrete can be tailored by controlling the replacement levels of conventional concrete ingredients.