Experimental Research on Optimum Combination of Reinforced Interlayer Bonding Materials between Base and Surface of Asphalt Pavement

Abstract

The interlayer bonding performance between the base and surface of pavement has a great influence on the integrity and durability of the whole pavement structure. To enhance the interlayer bonding effect of this heterogeneous structure, a reinforced interlayer bonding material with a combination of a permeable layer and a sealing layer was designed. A self-made shearing device and a pull-out device were used to carry out the interlayer shear strength and tensile strength tests on the composite specimen under different interlayer oil consumption and different temperature conditions, and the influences of various factors on the interlayer strength were analyzed. Finally, the optimum combination of the reinforced interlayer bonding materials between the base and surface of the asphalt pavement based on the regional ambient temperature characteristics was explored. The results show (1) at low and normal temperatures, the interlayer strength between the base and the surface layers increases with the increase in the tack coat rate, while the interlayer strength at high temperatures first increases and then decreases with the increase in the tack coat rate. When the prime coat rate is 0.6 L/m2, there is a characteristic cutoff point for the interlayer strength. (2) Compared with a single permeable layer material, the use of combination materials of “permeable layer + sealing layer” is beneficial to the improvement of the bonding performance between the base layer and the surface layer. (3) The combination materials of the prime coat and the tack coat should be selected reasonably according to the ambient temperature characteristics of the project area. For example, in areas without high temperatures in summer, choosing the PC-2–emulsified asphalt tack coat with an application rate of 0.6 L/m2+1.8 kg/m2 of asphalt mixed with fiber–rubber-modified asphalt gravel seals to enhance interlayer bonding performance; in areas with hot and high temperatures in summer, it is recommended to adjust the amount of rubber-modified asphalt in the aforementioned reinforced interlayer bonding measure to 0.9 kg/m2. The research results provide experimental support for the optimal design of reinforced interlayer bonding materials between the base and the surface of asphalt pavement based on regional ambient temperature.