Investigation of asphalt binder containing various crumb rubbers and asphalts

Crumb rubbers (CRs) have been proposed for the pavement because it is a waste materials and crumb rubbers modified asphalt pavement shows excellent performance. The effects of the asphalt, crumb rubbers type and crumb rubbers contents on the properties of crumb rubbers modified asphalt binders were investigated. The penetration, softening point, viscosity, dynamic shear rheometer (DSR), bending beam rheometer (BBR) and fluorescent microscope test were carried out. Experimental results indicated that the penetration, ductility and phase angle of asphalt binder was decreased, and the softening point, elastic recovery, viscosity, complex modulus and rutting parameter of asphalt was increased when crumb rubbers was added into asphalt. Compared with the ambient grinding crumb rubber (B), modified asphalt binder with the cryogenic grinding crumb rubber (A) has better pavement performance. In addition, the properties of crumb rubbers modified asphalt (A2) with 80/100 are better than that of modified asphalt with (A1) 60/80 at high and low temperature. The high swelling rate of crumb rubbers is favorable to prepare successfully crumb rubbers modified asphalt binder. The micrograph of crumb rubbers modified asphalt binders indicated that the light weight fraction in asphalt promoted a swelling of crumb rubbers in the modified asphalt binder, and crumb rubbers with high swelling rate improved the crumb rubbers disperse in asphalt to form continuous and interlocked phase.