EVALUATING THE PERFORMANCE OF ASPHALT RIENFORCEMENT LAYER COMPRISING POLYPROPYLENE GRANULES

Despite the widespread use of hot mix asphalt (HMA) Overlay as one of the most important methods of pavement maintenance, rehabilitation and development of roads, also the ease and speed of implementation and low costs, there are many disadvantages and problems that accompany the use, which is mostly due to reflection of the defects of layers the old pavement on which the asphalt reinforcement layer is based. Therefore, this study aims to prepare an asphalt mixture with a high performance and good specifications as overlay layer, which can resist the problems and defects that are exposed to it and increase its service life. Polypropylene granules of 19 mm particles size were used as an additive to the asphalt binder (AC 60-70), with percentages 1, 2, 3, 4, 5 and 7% of the optimum asphalt content weight. The volumetric and mechanical characteristics of mixture with this addition were evaluated by using Marshall stability and indirect tensile testing (ITS). The study showed that the use of 4% of the polypropylene granules of optimum asphalt weight gave optimal performance compared to the unmodified mix. The optimum performance of the asphalt concrete overlay during its design life, especially at high temperatures, was improved by improving the physical and mechanical properties of the asphalt mixture and by increasing its resistance to stresses is 32%.