Towards a high-performance asphalt concrete for extreme climatic conditions using asphaltenes and polyethylene terephthalate fibres

Abstract

Asphalt pavement experiences various deteriorations in different weather conditions due to the viscoelastic nature of asphalt binder. This study aims to develop a high-performance asphalt concrete (HPAC) for extreme temperature conditions by incorporating waste polyethylene terephthalate (PET) fibres and asphaltenes, a by-product from Alberta oil sands. First, performance of asphalt binder modified with asphaltenes is evaluated according to the Superpave performance grading (PG) system. Next, to improve low-temperature properties, HPAC mixtures modified with PET fibre at percentages of 0.05–0.30% are tested for compactibility to reflect field construction considerations. Then, performance tests including dynamic modulus; indirect tensile strength test at low temperatures; and Hamburg wheel-track at high temperature are conducted for an effective evaluation of the unmodified and modified mixtures that are prepared using a combination of the dry and wet mix methods. Results of binder PG tests reveal that with 12% asphaltenes, the modified binder is suitable for HPAC applications. The mixes with and without PET fibres exhibit similar compactibility and meet air void requirements of a maximum 6%, and incorporating PET fibres increases stiffness by up to 3.3%. Compared with the unmodified mixes, an optimum dosage of 0.15% PET fibre increases fracture energy by up to 27% at −10 °C and enhances tensile strength by up to 18% at 0 °C. The mixture with the optimum dosage also exhibits excellent rut resistance at 60 °C showing no signs of moisture damage sensitivity. As a result, it boasts a remarkable rutting resistance index that is five times higher than that of the control unmodified mix.