Low-Temperature Crack Resistance of Basalt Fiber-Reinforced Phase-Change Asphalt Mixture Based on Digital-Image Correlation Technology

DaoLu Tiaowen Cailiao (DTC) phase-change materials are important materials for improving the temperature adaptation of asphalt pavements. In order to improve the low-temperature crack resistance of asphalt pavements after adding DTC phase-change materials, basalt fiber-reinforced DTC phase-change asphalt mixtures with different basalt fiber dosages were prepared, and their mechanical properties, horizontal strain, and crack characteristics were analyzed using semicircular bending tests combined with digital-image correlation technology. The study showed that the basalt fiber increased the fracture strength of the phase-change asphalt mixture, delayed its damage time, improved its deformation capacity, reduced the crack development rate and damage degree of the interface, and enhanced its low-temperature crack resistance. The enhancement of low-temperature crack resistance of phase-change asphalt mixtures increased and then decreased, and the best effect was achieved when the dosage of basalt fiber was 3‰, which delayed the damage time of phase-change asphalt mixtures by 42.53 s, slowed down the crack expansion rate by 54.23%, and reduced the fractal dimension (D) and damage factor (Df) by 4.32% and 29.83%, respectively. In conclusion, basalt fibers can enhance the low-temperature crack resistance of phase-change asphalt mixtures, and the optimal dosage of basalt fiber is 3‰. Also, both D and Df showed a positive correlation pattern with KIC, but Df was more closely related to KIC, which shows that the new index Df based on the image analysis method and MATLAB software is reliable.