Relationship between crossover modulus and asphalt chemistry to oxidation process based on the RHEO+ method

Abstract

Fatigue damage is related to low-temperature conditions. Under this assumption, a question arises: why does fatigue occur at temperatures at which it should not and what methods should be used to study this phenomenon? Additionally, it is well known that oxidation causes asphalt to become brittle. Therefore, oxidation is usually associated with fatigue. As asphalt oxidizes, it changes its chemical composition affecting its rheology, the polarity increases, causing more rigid molecular structures to appear that directly affects its elastic response in turn. Consequently, the aim of this study is to propose a tool that relates chemistry and rheology. The method RHEO-PLUS (RHEO+) offers the possibility of correlating the viscoelastic mechanical properties measured in the rheometer, with the changes in the chemical composition of the oxidised asphalt. Based on RHEO+ it is possible to recognise whether the binder is in optimal conditions, aged (by loss of volatile fraction), or oxidised.