Eco-friendly high-strength concrete engineered by micro crumb rubber from recycled tires and plastics for railway components

Crumb rubber concrete (CRC) is one of the new construction materials, which has been developed as a by-product from wasted rubber tires and plastics. Most previous research focuses on applications of low-strength CRC that cannot linearly predict the high-strength counterpart. This paper thus presents a study into engineering characteristics of higher-strength CRC and its benefits to the environment, as well as to investigate the ability of micro crumb rubbers to enhance CRC’s mechanical properties. The results revealed that replacing fine aggregate with micro rubber particles caused the reduction in mechanical properties of concrete. However, due to the effect of micro size of rubber content and silica fume, the compressive strength of CRC achieved over 55 MPa, which will significantly benefit advanced construction of compliant structural systems. The tensile strength of CRC was higher than plain concrete by approximately 8.74% (splitting tensile strength) and 17.46% (flexural strength), but it was still lower than that of silica fume concrete. Moreover, CRCs also provided the ability to resist the crack of the concrete. It is found that suitable amount of rubber particles should not be more than 10%wt for novel and sustainable high-strength CRC in railway applications. The outcome of this study will help improve the database for materials in civil constructions. The adoption of sustainable high-strength CRC in railway practices will significantly minimise wastes from used rubber tires and plastics, thus paving a robust pathway for environmental impact to societies.