Investigation on Fracture Performance of Lightweight Epoxy Asphalt Concrete Based on Microstructure Characteristics

In order to investigate the fracture performance of lightweight epoxy asphalt concrete (LEAC) used in steel bridge deck pavement, experiments and numerical simulations were used to analyze the effect of lightweight aggregate (LWA) on fracture behavior of LEAC. The gradations of LEAC with different LWA contents were determined by the Marshall method, indirect tensile test with and without freeze-thaw processing were used to measure the indirect tensile strength and moisture stability of LEAC, and fracture properties were evaluated by three-point bending beam test at 15°C and −10°C. Also, internal structures of LEAC were scanned by X-ray CT device to develop three-dimensional finite element models (3D-FEM), and mechanical states of basalt aggregate, LWA, and epoxy asphalt mastic (EAM) were also studied. The results show that the LWA has an obvious influence on fracture properties of LEAC; LWA content 5% can significantly improve the fracture performance. EAM is the main bearing structure of LEAC; minimizing the impact on EAM can enhance the structural strength of LEAC. The mechanical state of internal structure can be calculated by 3D-FEM effectively, and the simulation results illustrate that the effect of LWA on stress distribution of EAM is obvious.