Analyzing the Cause of Asphalt Pavement Rut Damage of Heng-Zao Freeway

Asphalt mixture is a viscous-elastic-plastic material, its performance changes with the conditions of the environment temperature and traffic loading. Although lots of measures have been taken from design to construction to control asphalt pavement early damages, such as selecting raw material and asphalt cementation material, mixture gradation, mixture mechanics capability, construction technology, and testing standards. But most freeways in China have still suffered early damages. In south regions, rut and water damages are the main problem because of the rainy climate and high environment temperature. According to the investigations of the existing traffic of Heng-Zao freeway in Hunan province and the axle-load condition, rut depth, on-site core samples, extracting test, thickness, field sampling and indoor rut test, the paper firstly analyzes the present condition, evaluates the pavement performance and construction technology, then analyzes the gradation type, finally summarizes all the possible causes of serious rut of the freeway. These can provide the references for the pavement design and construction in south regions.