Experimental study on failure law of subgrade concrete with different damage base

The load-bearing damages of roads lead to road structure damages and engineering accidents. Field sampling of subgrade concrete was conducted as concrete constitutes the main road structure. Thus, the study of the failure law of subgrade concrete at different degrees of damage is of great importance as it ensures the safe operation of the road. The synchronous, acoustic emission (AE) monitoring test method of compressive loads was used to study the failure law of subgrade concrete after damage. The results indicate the following: (1) Based on the proposed damage base D', the damage states of concrete can be classified as serious or minor damages. The greater the damage base, the more serious would be the damage. (2) The strengths of slightly damaged specimens are higher than those of severely damaged specimens, and the elastic plasticity is better. The mechanical properties of severely damaged subgrade concrete are poor. (3) The AE count durations of severely damaged specimens are longer than those of lightly damaged specimen, the number of AE events is greater, the surface spalling is more evident, and the cracks develop more fully. The damage base is positively correlated with the dissipation energy density of concrete. The research results provide a theoretical basis for the quantitative division of road damage areas, monitoring and early warning.