Selection and Performance Evaluation on Tack Coat Oil Used in Ultra Thin Wearing Course

The ultra thin wearing course is a kind of preventive maintenance technology with excellent performance, and many advantages have been found including high wear resistance surface, low traffic noise, improved skid resistance, good waterproof performance and so on. In this paper, grinding tests were carried out to study the performance of four types of emulsified asphalt which were chosen to be used in step-constructed ultra thin wearing course. Based on the results of grinding tests, three types of emulsified asphalt were selected, and their bond properties were studied using direct shear tests. Test results show that low-grade emulsified asphalt possesses better bond properties and can be used to effectively prevent the damage of tack coat caused by construction vehicles. Thus low-grade emulsified asphalt is the preferred material to be used in step-constructed ultra thin wearing course.