Empirical rutting models of recycled mixtures containing CRM

Recycling of Reclaimed Asphalt Pavement (RAP) is now a normal practice because it saves aggregate resources and reduces environmental pollutants. The performance properties of asphalt mixture containing RAP could be improved by adding additives such as crumb rubber modifier (CRM). This study was conducted to investigate the contribution of CRM to the reduction of the rut depth in asphalt mixtures containing RAP through the establishment of rutting models. Lab tests including ten Superpave mix designs and rutting tests using Asphalt Pavement Analyzer (APA) were performed. Two types CRM, four percentages of rubber, and three percentages of RAP were used in this study. Results from the study include: (1) a logarithmic function fitted well with the curves showed the relationships between the rut depth and the repetitive loading time, (2) several good rutting models, which indicated that the CRM and the RAP were effective to reduce the rut depth, were determined between the rut depth with the percentages and types of CRM, and with percentages of RAP. Copyright ASCE 2006.