Laboratory Approach for the Selection of Compatible Epoxy-Modified Asphalt Binders

Existing research studies have shown that the performance of asphalt binders can be improved significantly through modification with epoxy materials as thermosetting polymers. Thermosetting polymers are produced by blending two liquid components containing a resin and a curing agent that react chemically to form a strong three-dimensional structure. Because variations in the asphalt binder composition strongly affect an asphalt binder's chemical reactivity, the compatibility of epoxy-modified asphalt (EMA) binders is influenced by the characteristics of base asphalt binder, epoxy resin, and curing agent, as well as the molecular interaction between these components. This study aimed to develop a practical yet effective laboratory approach to investigate the compatibility between two epoxy materials from different sources and four base asphalt binders with different chemical compositions. The experiment consisted of analyzing the SARA (saturates, aromatics, resins, and asphaltenes) fractions of the base asphalt binders, investigating the compatibility between the epoxy materials and the base asphalt binders by a modified storage stability test and Soxhlet asphalt extraction, and evaluating the morphology of EMA binders by fluorescence microscopy. Based on the research results, a laboratory protocol consisting of a modified storage stability test and Soxhlet asphalt extraction is suggested to discriminate the compatibility of EMA binders with an epoxy dosage rate of up to 25%.