Multi-Index Evaluation for Anticracking Performance of Epoxy Porous Asphalt Mixtures Based on Overlay Test

Porous asphalt pavement have been widely employed for various functions. However, due to its large voids and small contact area between particles, the reflective cracks results from semirigid base layer shrinkage cracking and buttom-up fatigue cracking are easy to occur, under long-term multifield coupling influenced by load, temperature, water, light and other factors of natural conditions. Therefore, improving asphalt crack resistance is a key issue. Using an overlay test with a high-viscosity porous asphalt mixture (HPA-13) as a control object, a multi-index evaluation was performed to test the anticracking performance of an epoxy porous asphalt mixture (EPA-13) under different temperatures and aging conditions. Results showed that epoxy asphalt binders can considerably improve the anticracking performance of porous asphalt mixtures; under the standard condition of 25°C, the number of loading cycles (N) of EPA-13 was 7.5 times higher than that of HPA-13. However, EPA-13 was greatly affected by low temperature and aging conditions; in particular, under the low temperature condition of 10°C, N decreased by 93.5%. In the multi-index evaluation of crack resistance, the gray correlation degree of each evaluation index followed the order of the allowable failure times with (J) > cumulative fracture energy (G) > displacement at the maximum load of the first cycle (LF) > fracture energy of the first cycle (GF) > average fracture energy (G*) > maximum load of the first cycle (F). It is recommended to use N, J, and G to evaluate the crack resistance of porous asphalt mixtures.