Investigating effect of temperature, aging and crumb rubber on the fracture characteristics of asphalt mixtures

Nowadays, the issue of waste rubber is a serious problem, each rubber which is thrown away is a threat for the health of community and environment. From the other point of view, the better pavement performance has led engineers toward the methods to modify asphalt and binder characteristics. Modified asphalt binder mainly improves factors such as rutting, cracking, fatigue, frictional resistance and stickiness of materials. Cracking in asphalt pavements generally take place at two medium and low temperatures. Cracking in asphalt mixtures occurs due to the growth of fine cracks, their joining together and finally larger cracks are formed. The material properties of the mixtures effect on their cracking potential. The purpose of this study was to evaluate the effect of temperature, aging and Crumb rubber on the failure properties of asphalt mixtures at medium and low temperatures. For this purpose, asphalt binder containing ۱۰% to ۱۵% crumb rubber with two sizes, fine and coarse, were made in a wet process. Asphalt mixtures with gap and dense gradation were designed using asphalt binder produced by Superpave method. To evaluate the failure characteristics of asphalt mixtures at medium and low temperatures (۲۵°C and -۱۲°C), a three-point flexural load test of a semicircular Bending sample (SCB) was used. Based on this, the failure characteristics of asphalt mixtures in two cases with short-term and long-term aging were evaluated. The results of the fracture test showed that the mixtures produced with the addition of crumb rubber have a high fracture toughness than the control mixture (without the addition of crumb rubber). Also, increasing the percentage of crumb rubber increased the fracture toughness of the mixture.

کلیدواژه ها:

Crumb Rubber Asphalt ، Temperature ، Aging ، Semicircular Bending (SCB)