Behavioural interface-bonding and chemical characterization of silane and wax based additives on latex modified asphalt binders

Abstract

This research aims to evaluate the behavioural interface-bonding response of modified asphalt binders towards different types of additives. In this study, 6% natural rubber latex (NRL) was added into a conventional asphalt binder (PEN 60/70) with the subsequent addition of 0.1% silane additive and 0.3% Gripper (wax based) additive, based on the weight of the asphalt binder. The chemical functional groups and the effects of oxidation on the specimens were determined from attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy. The contact angle and surface free energy of the asphalt binders were measured using a goniometer device and analysed using the DROP image Advanced Software. Results from this study showed that the rubberised asphalt binders, with or without additive incorporation, possessed improved resistance to oxidation due to increases in CH and OH functional group concentrations, as well as improved wettability rate. In addition, the NRL modified asphalt binder with additive incorporation exhibited outstanding performance compared with PEN 60/70 and NRL modified asphalt binder without additive. Both additive incorporations showcased comparable performances, but with the Gripper additive incorporation having a better performance at different ageing conditions. Overall, the additive addition as surfactant showcased the potentiality to improve the interfacial bonding behaviour of NRL modified asphalt binders with aggregate, hence improving resistance to permanent deformation and fatigue cracking.