Performance Evaluation of Different Particle Sizes of Crumb Rubber to Modify Bitumen for Flexible Pavement

Abstract

There are so much of waste tyres in Nigeria and disposal is not done properly. The wastes are usually burnt in the open space leading to environmental pollution. It is a very cheap commodity that can be used to modify bitumen in order to minimize the damage of pavement caused by increase in service traffic density, axle loading. The main aim of this study is to investigate the experimental performance of the bitumen modified with 10% by weight of crumb rubber varying its sizes. Marshall Stability Method was adopted for the mix design. Laboratory tests were performed on the modified bitumen using various sizes of crumb rubber and they were analysed. Four different categories of size of crumb rubber will be used, which are coarse (1 mm - 600 μm); medium size (600 μm - 300 μm); fine (300 μm150 μm); and superfine (150 μm - 75 μm). It was found that utilisation of waste tyres in highway construction can also reduce the frequency and cost of maintenance, this is very important for countries such as Nigeria with poor maintenance culture, the use of crumb rubber prolongs pavement life, driving comfort, the rheology of Crumb Rubber Modified Bitumen depends on crumb rubber quantity, particle size, type, bitumen composition, the mixing time, temperature, source and also the mixing process, either dry process or wet process. The researcher concludes that the best size of crumb rubber particle size for bitumen modification to obtain best results is the fine (0.3μm – 0.15μm).