Long term behaviour of cement concrete containing discarded tire rubber

Disposal of waste tire rubber has become one of the major environmental issues in the world. Every year millions of tires are discarded, thrown away or buried all over the world, representing a very serious threat to the ecology. It was estimated that, almost 1000 million tires end their service life every year and more than 50% are discarded without any treatment. One of the possible solutions for the use of waste tire rubber is to incorporate into cement concrete, to replace some of the natural aggregates. This paper presents the results of an experimental research to analyse the suitability of waste tire rubber as a partial substitute for natural fine aggregates in cement concrete. For the first time, three sizes of crumb rubber were mixed in definite percentages and replaced for fine aggregates from 0% to 20% in multiples of 2.5%. Tests were done to determine the mechanical properties, water absorption, resistance to sulphate attack, carbonation and porosity of these concrete samples. It was observed that the values of compressive strength, flexural tensile strength, pull-off strength and sulphate attack of rubberized concrete were lower than that of control mix; but up to a certain percentage, they gave better resistance to water absorption, and carbonation. It was concluded that there is a promising future for the use of discarded tire rubber as a partial substitute for fine aggregates in concrete, which can result in huge environmental and sustainability benefits.