Investigation on moisture susceptibility of asphalt mixtures containing ground tire rubber and de-vulcanized rubber

Abstract. The growing environmental threats of accumulating waste tires have raised the need to recycle and utilize them effectively, such as incorporating recycled crumb rubber in asphalt pavement mixtures. This paper aims to assess the incorporation of processed rubber from recycled tires on the moisture susceptibility of asphalt mixtures. For this purpose, two forms of recycled rubber were utilized; Ground Tire Rubber (GTR) and De-Vulcanized Rubber (DVR), with a constant content of 12.5% of bitumen by weight in a wet process. These modified binders were used to prepare asphalt mixture samples, which were then examined using the Indirect Tensile Strength test (ITS) in wet and dry conditions. In addition, the Tensile Strength Ratio (TSR), Marshall Stability, and flow were calculated. The results for all examined mixes were compared to the control mixture, namely the 60/70 pen Type 3 Marshal Mix. The results demonstrate that the measured TSR values, stability, flow, and volume of voids for all tested mixes were within acceptable limits. By meeting the objective of this study, it is well proven that the incorporation of recycled rubber was found to be effective in improving the moisture susceptibility of asphalt mixtures. Future studies are necessary to optimize the percentage of recycled rubber utilization, and to perform life cycle assessments of such mixtures.