Predict high and low temperature true grade of reclaimed asphalt pavement binder using the enhanced mortar testing approach

Accurate characterisation of reclaimed asphalt pavement (RAP) binder is an important prerequisite to successfully use RAP in new pavements. The conventional characterisation method is performed on the extracted and recovered RAP binders using harmful chemical solvents. A previous study proposed an enhanced mortar testing method that eliminates the use of chemical solvent by establishing a relationship between binder and mortar properties. As a follow-up, the objective of this study was to examine whether the enhanced mortar method is applicable at both high and low temperatures. The enhanced mortar method was evaluated using six RAP sources with distinct binder characteristics by comparing high and low temperature true grades measured from recovered RAP binders. Satisfactory results substantiate that the mortar methods can be used as an alternative to the solvent method, which lays a solid foundation for pursuing environmental and economic benefits associated with proper RAP usage.