The effect of crumb rubber modifier on the resistance of asphalt mixes to plastic deformation

This research analyzed the response of bituminous mixes manufactured with rubber to plastic deformation. For this purpose, a set of asphalt mixes containing different percentages of crumb rubber modifier (CRM) added by the dry process as well as the wet process were tested. It also compared the performance of a CRM mix to that of a mix made with high-performance polymer-modified bitumen. The mixes were assessed with the wheel-tracking test and the cyclic triaxial test. Their bearing capacity was also evaluated by determining their stiffness modulus at different temperatures. The results obtained showed that for the dosages and percentages of crumb rubber used, the addition of wet-process and dry-process CRM to asphalt mixes with conventional bitumen increased their resistance to plastic deformation. In fact, the performance of some CRM mixes was superior to that of the mix with high-performance modified bitumen. It also increased their stiffness modulus and creep modulus values and improved their resistance to plastic deformations caused by vehicle traffic loads. (c) 2012 Elsevier Ltd. All rights reserved.