Swelling process of rubber in asphalt and its effect on the structure and properties of rubber and asphalt

This paper deals with the mechanism of waste crumb rubber modified asphalt through simulating the swelling of rubber in asphalt using SBR sheet instead of waste rubber powder. Four groups analysis (SARA – saturates, aromatics, resins and asphaltines), XPS (X-ray Photoelectron Spectroscopy) and DSC (Differential Scanning Calorimeter) were used to characterize the structure and properties of asphalt and rubber in swelling experiment. The results reveal that the swelling of rubber in asphalt moved from a fast-growing process then level off to the equilibrium, and rubber absorbed only the light components in asphalt. The amount of asphalt components affects the properties of asphalt. During the swelling process, the amount of light constituents decreased accompanied by an increased softening point and decreased ductility and penetration.

▸ Swelling process of rubber increases rapidly in beginning then reaches equilibrium. ▸ Swelling index and the equilibrium swelling increase with increasing temperature. ▸ Only light components in asphalt can be absorbed, while heavy components cannot. ▸ Network structure of rubber is destroyed with swelling time increases. ▸ Light components show positive effect on low temperature properties of asphalt.