Effects of day-night temperature fluctuations on top-down cracking development in road structures

Top-down cracking has become a significant issue in road structures. Temperature is a key factor in the occurrence of top-down cracking. However, there is a lack of research on how day-night temperature fluctuations impact the propagation of top-down cracking in road structures, leading to an incomplete understanding of its development. This study employs the extended finite element method, which is an innovative approach for crack analysis, to create a simulation model of road structure with top-down cracking, integrating thermal boundary theory. The model's accuracy is confirmed through comparison with previous studies. The research then examines the temperature distribution and various influential factors, including ambient temperature, material properties, and cracking characteristics, using the stress intensity factor as the main indicator. It shows that temperature differential and wind speed are key factors influencing the open and shear modes of top-down cracking. Additionally, the study explores the propagation path of top-down cracking in road structure under cyclic temperature loading. Top-down cracking propagates linearly downward within road structure, with displacement showing an increasing trend as the number of temperature cycles rises. The findings provide new insights into the thermally-induced mechanisms behind top-down cracking development in road structures.