Influence of Crumbed Para Rubber Modifier in Aggregate Blend on Deformation Resistance Properties of Hot Mix Asphalt

Abstract

This research presents the influence of crumbed para rubber which is added into a portion of aggregate in hot mix asphalt (HMA) during the batch mixing process or called “Dry Process”. The dry process has an advantage on its simplicity of quality inspection and less modification in the hot mix plant production process. This study has investigated the effects of adding crumbed para rubber particles on the engineering properties related to permanent deformation resistance of asphalt concrete. In this study, the asphalt mixture is prepared via Marshall Mix design, which contained with limestone and asphalt cement of Pen 60/70 at 5.4% by total weight. Crumbed para rubber at 2% by total volume was added in asphalt mixture via two methods, dispersive mixing method and layer method. The specimens that prepared from each method were compacted to cylinder shape according to the requirement of testing standard using Gyratory compactor. The specimens were tested to find the indirect tensile strength values according to ASTM D 6931-12, resilient modulus values according to ASTM D 4123-82 and dynamic creep test according to AS 2891.12.1_1995. The results showed that adding crumbed para rubber in aggregate increasing the engineering properties of asphalt concrete such as the strength, the elastic recovery, the deformation resistance and the longer service life. The dispersive mixing method is the most effective method and introduces many advantages than other methods such as less complexity in mixture production and road construction, in the other hand, this method contains more content of para rubber to modification than “Wet-Para modified AC.” From the results, Mixtures from dispersive mixing method shows a better performance in deformation resistance for 3 times than conventional mixture