EFFORTS TO IMPROVEMENT THE STRUCTURE OF COLD JOINT TO EXTEND THE LIFE OF ASPHALT PAVEMENT

<p> As the service life increases on the expressway, a larger number of repair work sites are required to work on not only a binder course but also an upper base course. Based on this situation, we conducted a nationwide field survey. As a result, it was clarified that the asphalt pavement was damaged such as fatigue cracks and permanent deformation, and that the weakening of the lower base course and the interlayer debonding. To extend the service life of asphalt pavement, it is important and the simplest method to increase the adhesive strength of interlayer. However, a method that can appropriately evaluate these methods has not yet been established. Therefore, we developed a new testing apparatus and method simulating the real damage phenomenon in fields. Regarding the vertical cold joints, different characteristics were confirmed depending on the material. On the other hand, for the interlayer of asphalt pavement, we used this test that reproduced the breakage of adhesion due to water seen on the actual road and evaluated several types of tack coats. In this report, we report on the technical standardization of the application of materials with excellent adhesiveness and water-stopping properties for the vertical cold joint. In addition, we clarified the problem that any of the tack coats currently applied can not maintain the necessary bonding property in summer condition.</p>