Stone Matrix Asphalt Using Aggregates Modified with Waste Plastics

Stone matrix asphalt (SMA) is a gap-graded asphalt mixture performing better than conventional dense-graded mixtures. It contains a high concentration of coarse aggregates (forming stone-on-stone contact between them) and high asphalt content. The coarse aggregate skeleton results in better load distribution and the high asphalt content adds durability to the mixture. Due to the high mastic (filler and asphalt) content, there is possibility of drain down during various stages in construction. SMA mix should be prepared with a suitable stabilizing additive to prevent the drain down of mastic material from the mixture. In this study, SMA mixtures are prepared in a Super pave Gyratory Compactor (SGC) with shredded waste plastics, which are mixed with aggregates prior to the addition of Viscosity Graded (VG) - 30 asphalt. Mixtures are prepared with asphalt contents of 5.0 to 7.0 per cent (by weight of aggregates) and stabilizer contents of 0, 4, 8, 12 and 16 per cent (by weight of asphalt). Volumetric and Marshall properties, tensile strength, and moisture susceptibility characteristics are determined. From the laboratory studies, it is observed that addition of waste plastics in shredded form can be used instead of stabilizers by controlling the drain down and enhancing the performance.