DEVELOPMENT OF A PREMIUM COLD MIX ASPHALT

Abstract

Cold mix asphalt produced using conventional emulsion and limestone filler has three main disadvantages, namely low early strength due to high amount of water within the mix, long curing time ranging from 2-24 months and high air voids content. In this study, the effect of a novel technology for producing high-quality cold mix asphalt using modified bitumen emulsion has been investigated in terms of indirect tensile stiffness modulus. the effect of a novel technology for homogenizing a bitumen emulsion on its viscosity, particle size and particle size distribution has been investigated. Ultrasound technology has been used to reduce the viscosity and the size of the bitumen droplets. Different samples of cationic bitumen emulsion (C50B4) have been prepared with different treatment durations (0, 5, 7, 10, 12.5, 15, 30, 45 and 60) min. The results have shown a reduction in the viscosity of the bitumen emulsion at treatment times from 5-15 min. The viscosity has been decreased by 28% after 10 min treatment for the emulsion compared to the untreated sample. This reduction indicated a uniform droplet size distribution. In addition, the particle size measurements revealed that the 7 min treatment showed a significant reduction in the D 50 , which was 84.5%, D 10 , was 85.89%, and D 90 was 90.28% compared to the untreated bitumen emulsion. The results reported contains a comparison between the viscosity of the emulsions, and the indirect tensile stiffness modulus of a control conventional cold mix asphalt and the new high quality cold mix asphalt with low viscosity. Interestingly, the reduction of the 28% in the viscosity of the new emulsion causes an improvement of the indirect tensile stiffness modulus to 216%, which indicates an outstanding achievement.