Use of Crumb Rubber as an Additive in Asphalt Concrete Mixture

As the rapidly growing number of vehicles in Indonesia, the waste of tire rubber becomes a major environmental concern. The use of crumb rubber, which is the recycled tire rubber, as an additive in hot mix asphalt mixture is considered as a sustainable construction method. The purpose of this study was to investigate the effect of adding crumb rubber to asphalt mixture using wet process. The laboratory hot mix asphalt design tests were done by Marshall Method procedure. In this study, two different crumb rubber contents (1% and 2% by weight of asphalt mixture) and two different crumb rubber sizes (#40 and #80) were investigated. A comparative study was done among the unmodified and modified asphalt concrete mixtures considering the Marshall Stability value and the volumetric properties. The results showed that crumb rubber is recommended as an additive in asphalt mixture, as all the test results are within the standard requirements. The addition of crumb rubber tended to increase the strength and quality of asphalt mixture. However, it should be more concern about durability of asphalt mixture because of the lower asphalt content in crumb rubber modified asphalt mixture.