Strength and Durability Characteristics of High Strength Concrete made with Scrap Tire Crumb Rubber

Abstract

The emphasis on environmental protection highlights the need to incorporate the 3R principle i.e., recycle, reuse, and reduce into the construction sector to prevent environmental degradation and make effective use of waste materials. Unrestrained human activities have led to the overexploitation of natural resources, damaging the surrounding ecosystems. It is crucial to decrease our reliance on natural resources by minimizing their use and focusing on recycling waste. The handling of waste materials encompasses a wide range of challenges, including but not limited to efficient collection and transportation, environmentally safe disposal or recycling methods, minimising health and environmental risks, implementing effective waste management policies and regulations etc. The end-of-life tires, referred to as ELTs, is one such waste material. The present study aims to use ELTs, in the form of crumb rubber in high strength concrete. The study evaluates the feasibility of incorporating crumb rubber as a partial sand replacement in high-strength concrete, with substitutions of up to 30%. Metakaolin content of 15% of weight of cement was chosen as supplementary cementitious material to achieve high strength and counter the mechanical strength losses due to presence of the crumb in the concrete mix. This content was chosen based on the initial trials performed, as 15% of metakaolin provided the highest compressive strength performance. Various tests were performed to evaluate fresh properties i.e. workability and density. Strength and durability properties were evaluated for up to a period of 365 days. Non-destructive tests i.e., ultrasonic pulse velocity and rebound hammer, were also performed to establish their relationship with compressive strength. The performance of rubberised high strength concrete under aggressive environment, which consisted of sulfate attack (sodium sulphate), chloride attack and acid attack (sulfuric acid) was also evaluated for up to a 365 days period. The microstructural examination was also