LAUSR

Warm Mix Asphalt (WMA) is an innovative technology that aims at decreasing the mixing and compaction temperature of asphalt mixtures as compared to the conventional Hot Mix Asphalt (HMA) thereby reducing harmful emissions and fuel consumption. The rubberized asphalt mixtures are found to have better physical and strength properties, but they are compacted at a higher temperature than that of conventional mixes. In this study Cashew Nut Shell Liquid (CNSL), an organic additive, was added from 0.5% to 3 % by weight of the binder at an increment of 0.5 % to modify the bitumen. The optimum content of CNSL to reduce the viscosity was found to be 2% and the viscosity reduction was 44.4 % at 140°C The modified NRMB (Natural Rubber Modified Bitumen) was used to prepare Dense Bituminous Macadam (DBM) and a comparison of volumetric, stability and rutting characteristics of both Natural Rubber modified Hot Mix Asphalt (RHMA) and Natural Rubber modified Warm Mix Asphalt with CNSL additive (RWMA) was made. Storage stability results indicated that there was no phase separation between rubberized bitumen and additive at high temperature and will act as uniform blend at high temperatures. Dynamic Shear Rheometer test results showed that the addition of CNSL to rubberized bitumen increased the values of G*/sinδ and could improve the resistance of asphalt binder against rutting. Stability value of RWMA was 11.5 % higher than that of RHMA and rutting depth was 10.1 % less than that of RHMA. The fatigue strength results obtained from Repeated Load Testing showed that the number of cycles to failure at 20% stress level was 9.04 % more for RWMA than RHMA. All volumetric properties of both RHMA and RWMA were within the limits specified by Ministry of Road Transport and highways (MoRTH) 2013. The statistical analysis authenticates the experimental findings. ANOVA analysis for Marshall Quotient revealed that RWMA had improved compaction characteristics than RHMA and the result for rutting and fatigue strength showed that the additive CSNL and temperature had significant effect on rutting resistance and fatigue life.