Innovative application of waste polyethylene terephthalate (PET) derived additive as an antistripping agent for asphalt mixture : Experimental investigation and molecular dynamics simulation

Moisture-induced damage represents one of the major challenges to the durability of asphalt pavement, which may lead to various premature distresses, such as cracking, ravelling and potholes. To reduce the moisture-induced damages, antistripping agents have been commonly used in asphalt mixtures. On the other hand, the fast-growing waste polyethylene terephthalate (PET) from the end-of-life plastic products poses a serious problem to the environment. How to recycle and reuse the waste PET is becoming a major concern. This study aims to develop a value-added recycling approach of reusing waste PET as an antistripping agent for asphalt mixture. To achieve this objective, waste PET was first collected and went through an aminolysis reaction to yield the amine-based PET additive, which was used to modify bitumen. The infrared spectrum of the PET additive was then characterized, followed by the evaluation of moisture susceptibility through the boiling test and indirect tensile strength (ITS) test. In addition, molecular dynamics (MD) simulation was conducted to analyze the effect of the PET additive on the density and the cohesive energy density (CED) of the binder, and the interface bonding between binder and aggregate at the molecular level. The results from both experiments and MD simulation consistently indicate that the waste PET derived additive can effectively increase the resistance to moisture-induced damage of asphalt mixture.