A Review of Compatibility Evaluation Methods and Improvement Measures Between Rubber Powder and Base Asphalt

The increasing number of waste rubber tires has attracted the attention of more and more researchers. Rubber asphalt has better performance compared with original asphalt. However, the compatibility between rubber powder and asphalt is poor because of the difference in physical and chemical properties and the improvement of high-temperature performance of asphalt by rubber powder is very limited. The compatibility between rubber powder and original asphalt plays a key role in the storage stability and rheological performance of rubber asphalt. This paper provides a comprehensive overview of rubber asphalt, factors influencing compatibility, compatibility evaluation methods, and improvement approaches. Desired compatibility results from the fact that rubber powder is cross-linked with molecules of original asphalt and evenly distributed in the original asphalt, forming a homogeneous system. Starting from the preparation process of rubber asphalt, the best preparation process was summarized. Then the activity of rubber powder is improved by physical and chemical methods, or other additives are added to finally promote the formation of a cross-linking network structure between rubber powder and original asphalt. Rheological method is the most widely used method in compatibility evaluation, but it is gradually accepted by researchers to evaluate the compatibility by observing the molecular morphology of rubber asphalt.