The Effect of Reclaim Tire Rubber as Additive in Minimizing Reflective Cracking

Abstract

The rehabilitation of cracked pavement by overlaying, without any improvement, is rarely a durable solution, as the cracks rapidly propagate through the new asphalt layer. Cracks reflection through the road structure is one of the main causes of premature pavement deterioration which shortens the service life of overlays. The prime objective of this research is find the suitable remedies for this problem, by optimizing overlay asphalt mix design after considering the properties of various available material types, amounts and exposure conditions, Which include: two grades and five contents of asphalt cement, two aggregate maximum sizes and one type with different contents of asphalt modifier additives with reclaim tire rubber. A total of 160 Marshall Specimens were prepared and tested by Marshall, Indirect tensile and Creep tests at different temperature. To simulate the overlay performance under a rolling tire, 18 compacted asphalt concrete beam samples are tested using a modified wheel tracking apparatus. It can be concluded that mixes with optimum content of asphalt cement grade (40-50), 12.5 mm aggregate maximum size and 3% of reclaim tire rubber (by wt. of asphalt) give the maximum resistance to reflection cracking.