Crumb rubber modified bitumen and quarry dust in flexible pavements

Abstract

In urban region, the crumb rubber materials is causing alarming environmental issues and can be utilized as a partial replacement of bitumen with waste crumb rubber materials to reduce the construction cost of top layer of flexible pavements. The comparison of pure bitumen and modified bitumen using waste crumb rubber is studied experimentally and discussed about the resistance against fatigue cracks, rutting cracks, strength of bitumen road and durability of modified bitumen at both high temperatures and low temperatures using “Marshall Stability Analysis”. The quarry dust, which is another waste generating from the quarries, is used as fine aggregate and filler. 15% of 20mm, 25% of 12.5mm, and 15% of 6 mm as coarse aggregate and 45% of quarry dust as fine aggregate and filler material is used. Waste crumb rubber materials are added to pure bitumen using wet process with percentage of 5%, 10%, 15% and 20% crumb rubber with size of 0.300mm to 0.150mm. Laboratory results indicated the crumb rubber can incur high elastic behavior, low penetration and high softening point compared to pure bitumen. Also high stability and flow values of modified bitumen compared to pure bitumen concrete mix at both low and high temperatures.