Effect of warm-mixing wax's molecular weights on microstructure, rheological and mechanical properties of asphalt composites

The application of wax-based warm-mixing agents in pavement construction can effectively decrease the compaction temperatures of asphalt, leading to a reduction in greenhouse and harmful gas emissions. At present, many commercial waxes with different molecular weights are available on the market, but, wax with a high molecular weight can negatively impact the duration of the asphalt pavement. The effects of various warm -mixing agents on the structure and characteristics of asphalt composites were thoroughly investigated to quantify the molecular weights of wax. The obtained results suggested that the wax with an optimal molecular weight range of 1300 g/mol to 1500 g/mol had a significant viscosity-reducing effect and effectively increased resistance of asphalt composites against deformation and rutting at high temperatures; although the high -temperature features of asphalt composites were harmed by wax with low molecular weights (400-700 g/ mol), it could further improve the low-temperature features of asphalt composites, particularly the resistance to low-temperature cracking. This work offers a useful method for balancing the high-and low-temperature properties of asphalt pavement by tuning waxes' molecular weights.