Contribution of Crumb Rubber in the Aging Process of Asphalt Concrete

Implementation of sustainable solutions in the road construction industry is considered as one of the major research topics worldwide. The impact of aging process on the properties of asphalt cement and asphalt concrete was investigated using both of short and long-term aging. Scrap tire rubber was introduced into asphalt cement to modify its physical and rheological properties. Two percentages of crumb rubber (8 and 16) percent by weight of asphalt cement have been tried to modify the properties of asphalt cement, and to investigate its contribution in the aging process. Such modified asphalt was implemented in the construction of asphalt concrete. Marshal, Resilient Modulus, and tensile properties of rubber-modified asphalt concrete were tested and compared with different aging periods and with that of reference mix. The results show that aging for 7 hours of asphalt cement, make the asphalt stiffer, that lead to decreased penetration by an average value of (47.24%), ductility (49.6%) and increased softening point (10.75%) and creep stiffness (79.25%). It was concluded that 8% of crumb rubber is able to overcome the negative impact of short and long term aging on overall asphalt cement and asphalt concrete properties, and improves the rutting resistance at 1000 repetition by (32.4 % and 57.3%) for short and long term aging respectively.