Investigation on Recycling Application of Waste Rubber Tyres in Concrete

Abstract

Rational and sustainable disposing and recycling of waste rubber tyres (WRT) has become a challenge with their numbers increasing and accumulating. According to statistics, the cumulative annual generation of WRT is about 1.5 billion; they cannot be degraded and are difficult to recycle. WRT was generally buried in the landfills, stacked in open storage, or used as fuel; which not only pollutes the environment but also wastes resources. The application of waste rubber powder in concrete not only improves the ductility of concrete but provides a new solution to the problem of waste rubber pollution. However, the workability and mechanical properties of concrete are greatly affected due to the poor compatibility between rubber particles and the cement matrix. To improve these weaknesses, a novel method to modify WRP by combining the organic and inorganic mixed slurry coating and filling effect was proposed in this study. The particle size distribution of rubber particles before and after modification, the effect of rubber particles on hydration heat and rheology of cement mortar, and interfacial bonding between rubber particles and cement matrix were explored. The compressive strength and splitting tensile strength of concrete with WRP and modified WRP (MRA) were determined. The results demonstrate this modification method was very effective, and the structure and properties of WRP were significantly improved. Under the same volume replacement percentage, the compressive strength and splitting tensile of concrete increased by 70.0% and 46.1%, respectively. The cavitation phenomenon between rubber particle and cement matrix disappeared, and the interface bonding was significantly improved.