Effects of long-term aging on asphalt mixes containing SBS and PP-polymer

Abstract

The bulk of researches on styrene-butadiene-styrene (SBS) and polypropylene (PP) polymers for use in asphalt mixes are focused on the performance properties of these mixes without considering aging effects. SBS and PP are abounding and cheapest (on the order of 3.0–4.0 USD/kg) compared with commonly modifiers. In this research, the influence of long-term aging at 85 ± 3 °C for 120 ± 0.5 h on SBS and PP-mixes properties in terms of: stability, rigidity, resilient modulus, indirect tensile strength at 25 and 60 °C, tensile strength ratio, and rutting were determined and compared. Further pavement life and responses in terms of: fatigue strain, rutting strain, surface deflection, and percentage increase in pavement life were assessed using multi-layer elastic analysis software (BISAR). The test results of SBS-mixes showed higher resilient modulus and resistance to moisture damage, with lower stability and resistance to rutting than PP-mixes. BISAR analyses show that SBS-mixes were higher fatigue life than PP-mixes. Generally, results showed that long-term aging improves the performance of SBS and PP mixes.