Asphalt pavement heat insulation bonding layer material: Mechanical, bonding properties and heat preservation efficacy

To enhance the usage performance of asphalt pavement under extreme climate temperatures, the heat insulation performance of asphalt pavement bonding layer was endowed, and the mechanical properties, bonding performance, and durability of heat insulation bonding layer materials (HIBLM) were revealed. A method for evaluating the heat preservation effect was designed, and the heat preservation performance of HIBLM was compared and evaluated. The results show that compared with hollow glass beads (HGB)-HIBLM and expanded perlite (EP)-HIBLM, the mechanical properties of floating beads (FB)-HIBLM are outstanding, and the 7 d tensile strength can be increased by 6%–12%. The bonding strength of FB-HIBLM and EP-HIBLM is the best, which can increase by 23%–28% compared to HGB-HIBLM. After 30 d temperature change cycles or 15 d immersion in water, the mechanical and interlayer bonding properties of HGB-HIBLM, FB-HIBLM, and EP-HIBLM decrease less than those of ordinary emulsified asphalt (OEA), showing excellent durability. In the 100 min cooling test, the average cooling rate of the lower surface of the HIBLM decreased by 17%–18%. At 85–100 min, the maximum heat preservation temperature differences of HGB-HIBLM, FB-HIBLM, and EP-HIBLM are 4.8 °C, 4.7 °C and 4.7 °C, respectively, and the heat preservation values are 2.5 °C, 2.3 °C and 2.2 °C, respectively.