Using Crumb of Tires in Hot Asphalt Mixture as a Part of Aggregate

Abstract

Scrap tires are a major part of the global solid waste management problem. In recent years, the problem of waste tires has become very acute that there is an urgent need to find an optimal and efficient way to use scrap tires in asphalt mixtures. The previous studies showed that the utilization of crumb of tires has more effect on asphalt mixture performance, which is represented increasing in the Marshall Stability and increasing crumb of tires causes increasing in Marshall Flow and increasing in air voids content additionally more than original mixes. This paper used crumb of tires in asphalt mixture as a part of aggregate. Three sizes of the grade of crumb tires were used in asphalt mixture No. 4 (4.75 mm), No. 8 (2.36) mm and No. 50 (300µmm). Three percentages of asphalt binder (4, 5 and 6) by weight with three percentages of crumb tires (2, 4 and 8) % by weight also were used with aggregates for preparing asphalt mixture specimens. Asphalt mixture specimens were conducted according to Marshall Methods. Thirty-six specimens were equipped for evaluating Marshall Properties (Marshall Stability and flow, air voids percentage, bulk density, maximum bulk density, and Marshall Stiffness). Indirect Tensile Strength test (ITS) has been applied to obtain the cracking resistance of asphalt mixture using twenty-four specimens, which contains crumb tires. The results showed that the applying of the crumb tires has a significant performance of asphalt mixture by increasing the Marshall stability, flow, air voids, and decreasing bulk density and indirect tensile strength compared to the original mixtures.