Utilization of pozzolanic material to improve the mechanical properties of crumb rubber concrete as rigid pavement - A review

Abstract

Over the last few decades, waste tires have piled to an explicitly large number, posing a serious environmental threat in the worldwide. By reusing waste tires in concrete mixes in the form of crumb rubber, it was reported that crumb rubber improved concrete energy absorption, delayed the deformation time, and prevented sudden failure, which could enhance the rigid pavement performance. However, crumb rubber tends to reduce concrete strength primarily because of a lack of bonding between the smooth rubber surfaces and cement paste, resulting in a tiny gap in the concrete ITZ. The decrease in strength caused by crumb rubber can be solved by utilizing pozzolanic materials such as nano-silica, fly ash, and rice husk ash as additive materials or partial replacement of cement to improve the concrete pore structure through pozzolanic reaction and to enhance the adhesion between crumb rubber and cement. It was shown that pozzolanic materials, as mentioned above, managed to improve the strength of crumb rubber concrete with nano-silica showed the best effectiveness compared to fly ash and rice husk ash in creating high-strength crumb rubber concrete for application as a rigid pavement material.