Research on the Influence Factors of Low-Temperature Crack Resistance of Semiflexible Pavement Materials Based on Freezing Test

To study the influence factors of low-temperature performance of semi-flexible pavement materials, a freezing test was conducted, and the cracking temperature was used as the evaluation index to study the influence of asphalt type (90 matrix asphalt, SBS-modified asphalt, TPS high-viscosity modified asphalt), cement-based grout material types (ordinary grout, rubber powder grout, emulsified asphalt grout), and skeleton void ratio (20%, 24%, 28%, 32%) on the low-temperature performance of semi-flexible pavement materials. Results indicate that the freezing test can effectively distinguish the low-temperature crack resistance improvement benefits of semi-flexible pavement materials with different asphalt, cement-based grouting materials, and skeleton void ratios. Cracking temperature can effectively evaluate the low-temperature performance of semi-flexible pavement materials. The substrate void ratio is in the range of 20%-32%, and the cracking temperature changes with the increase in the substrate void ratio, decreasing initially and then rising. When the void ratio is around 24%, the best low-temperature performance of semi-flexible materials is achieved. The improvement effect of the elasticity of grout on the low-temperature crack resistance of semi-flexible pavement materials is obvious; the improvement effect of emulsified asphalt grout on the low-temperature performance of semi-flexible pavement materials is better than that of rubber powder grout. After the modified asphalt is used in the substrate, the cracking temperature is reduced by 31.4%-38.3%, which is much greater than the effect of grouting. At the same time, the elasticity of the base asphalt is more effective than the viscosity increase in improving the low-temperature crack resistance of semi-flexible materials.