Improving asphalt concrete mixtures resistance to rapid freeze-thaw effect using HIPS polymer

Abstract

Two methods of High Impact Polystyrene polymer (HIPS) addition to the asphalt concrete mixtures (AC) were used to evaluate the effect of freeze-thaw (FT) cycles on the performance of unmodified and modified AC by HIPS; supplementary and additional HIPS polymer as asphalt aggregates. Various polymer contents were used to modify the AC in both methods namely 0% (control), 5%, 10%, 15%, and 20%. Marshall stability, flow, bulk density, Indirect Tensile Strength (ITS) tests were performed on control and modified samples. Non-destructive test was evaluated by Ultrasonic Pulse Velocity. In the first method, replacing mineral filler by HIPS polymer in AC by 10% lead to the increase of density by 1%, stability by 113%, retained stability by 52%, and ITS by 56% compared to control specimen, these results show a reduction in the damage caused by 8 weeks of FT cycles by 14% for modified AC compared to unmodified AC. However, modifying AC by the second method did not provide promising results, the velocity within the specimen has dropped by 20.9% at 10% HIPS additive before FT effect compared to control. The results of the first method revealed the feasibility of improving AC by HIPS polymer to resist effective FT cycles.