Rutting deformation of gap-graded hot-mix asphalt with added of waste tire rubber

Used tires are among the many types of wastes found in several countries. Such a waste actually can be reduced by transforming it into suitable material to be added to road pavement mixtures. This added material made from used tires is called Crumb Rubber (CR). In the present study, asphalt was obtained from semi-extracted asbuton as a binder aggregate with gap-graded specifications. The use of semi-extracted asbuton is aimed at replacing a part of the conventionally used oil asphalt to obtain a more economical asphalt mixture for asphalt pavement construction in Indonesia. Furthermore, gap-graded aggregates may improve the performances of surface layers. Tests were conducted to find the optimum asphalt content value through the Marshall test. This asphalt mixture was infused with CR in varying proportions of 0.48%, 0.96%, and 1.44%. The addition of CR as a certain percentage of gap-graded hot-mix asphalt can improve rutting deformation resistance. Tests with composition in crumb rubber were carried out using a wheel-tracking machine (WTM) to determine the depth of rutting deformation in a flexible pavement. The results of this test reveal the best composition of CR and aggregate based on the path deformation.