Laboratory study and performance evaluation of a new type of prime coat material used on cement treated base

- Comparison and selection for the optimum proportioning of prime coat material were conducted.
- The optimum composition of the new prime coat material were chosen.
- The failure surface of the new prime coat was analyzed after the interlayer pull-out test and shear test.

Through many pavement structure inspections, it is found that the interlayer bonding is not adequate. To solve this problem, this study attempt to develop a new type of high-performance prime coat material. Through viscosity tests, exudation-pressure test, high-temperature test and uniaxial penetration test, the penetrability and solidification effects of new prime coat material on the upper surface of the cement treated base(CTB) are evaluated. Based on the results, the optimum proportioning is determined. The improvements on interlayer bonding and pavement performance of the new prime coat material are also evaluated by accelerated loading test, interlayer pull-out test and shear test. The existing test results show that using a mixture of water soluble epoxy resin and emulsified asphalt mixture as the prime coat material of CTB can bring remarkable penetrability, surface consolidation and interlayer bonding effect. Compared with the existing normal emulsified asphalt prime coat material, the interlayer bonding performance of this new prime coat material is significantly improved and the effect of dumper's wheel load is relatively minor. Thus, the mixture of water soluble epoxy resin and emulsified asphalt can be used as a next-generation upgraded prime coat material of CTB.