Generation and propagation of reflective cracking and thermal cracking of asphalt pavement in cold regions of China

In order to resist heavy traffic loads and reduce the risk of surface damage, rutting and settlements over time, cement-treated materials are often utilized in pavement construction in China. However, these materials exhibit drying and thermal shrinkage, resulting in cracking in the cement-treated materials. These cracking may further result in reflective cracking of the asphalt material during service. Thermal cracking is another type of cracking in the cold region of China. All these cracking generate with the micro-cracks inside the materials under tensile stress and develop with the effects of traffic and environmental loadings. As the initiated micro-cracks are invisible, it is rather difficult to predict where and when the macro-cracks will appear. In this study, the distributed optical fibre sensors were separately embedded in the cement-treated base layer, the bottom layer, and the middle layer. Then the strain distribution along with the distributed optical fibre sensors was measured every 6 months since the winter of 2018. We have found something useful for further interpretation and analysis about how the reflective cracking and thermal cracking in asphalt pavement generate and propagate.