THE EFFECT OF CRUMB RUBBER ADDITIVE INTO HOT MIX ASPHALT PERFORMANCE

Abstract

Many researches have been conducted in finding alternative materials in order to be used as a modifier in asphalt mixture for the purpose of improving its properties. This thesis presents a study of laboratory evaluation on the performance of hot-mixed asphalt (HMA) using crumb rubber as an additive. It is noted that crumb rubber was identified to have potency as a modifier in HMA due to the elastic behavior exposed by the rubber particles, especially in reducing the rutting potential. In this research, fine crumb rubber passing sieve no 200 obtained by ambient-temperature grinding process from discarded truck tires, was used to modify asphalt cement. The fine crumb rubber with different contents, i.e. 3%, 5% and 15%, was incorporated into the mixture by using wet process method. The samples of asphalt mixtures were prepared and tested by following Marshall design procedure. The results showed that the addition of crumb rubber in asphalt cement made the modified asphalt became less temperature-susceptible. The use of crumb rubber asphalt in asphalt mixture, especially for 3% crumb rubber content, could produce more and less comparable performance to mixture with virgin asphalt, in terms of load-deflection and volumetric properties. One drawback of the use of crumb rubber in the mixture is that it is required more asphalt content than that of mixture without crumb rubber. This is contributed by the nature of crumb rubber material that has high water or asphalt absorption.