Using semicircular bending test to study the influence factors of low temperature cracking resistance of asphalt mixture

Abstract

Low-temperature cracking (LTC) is one of the main types of asphalt pavement distress, which can be affected by various influencing factors. This paper carries out a systematic study on the influence of various factors on the crack resistance of asphalt mixtures using a semicircular bending test. The specific results are as follows: At low temperatures (0°C and below), cracks develop rapidly after the asphalt mixture reaches its peak force, and the asphalt mixture shows brittle damage. Basalt asphalt mixtures have significantly better LTC resistance than limestone. The smaller the maximum nominal size of the aggregate, the better the LTC resistance of the asphalt mixture. The LTC resistance of SBS-modified asphalt mixtures is significantly better than that of Pen.70 virgin asphalt mixtures. The cracking resistance of asphalt mixtures increases after water saturation under non-low-temperature conditions, while water saturation significantly reduces the LTC resistance of asphalt mixtures. The aging can significantly reduce the LTC resistance of asphalt mixtures. Based on the random forest method, it is concluded that temperature, asphalt binder type, and aging are the key factors affecting LTC, the normalized importance score is 39.59 %, 21.91 %, and 11.8 %, respectively. Developing modified asphalt binders with low-temperature sensitivity, aging resistance, high toughness, and high adhesion is the key technology to improve the LTC resistance of asphalt mixture from the material itself.