Investigation on the epoxy/polyurethane modified asphalt binder cured with bio-based curing agent: Properties and optimization

As a renewable resource, the use of bio-based curing agents for asphalt binder preparation can help reduce the consumption of non-renewable resources and promote the sustainable development of construction facilities. In this study, an attempt was made to use a bio-based epoxy curing agent, namely, malepimaric anhydride (MPA), for the preparation of epoxy (EP)/polyurethane (PU) modified asphalt binders. The mechanical properties, curing characteristics, viscosity, thermal storage stability, and micromorphology of the EP/MPA/PU (EMPU)-modified asphalt binder were investigated based on tests. The curing conditions were determined, and the mixing parameters were optimized. Besides, the rheological properties and cost were compared and analyzed. The results revealed that the optimum curing conditions for the EMPU-modified asphalt binder were 135 °C/2h + 150 °C/2h. When the modifier content was 50 wt%, a stable cross-linked network structure was formed inside the binder. The EMPU-modified asphalt binder exhibited excellent mechanical properties and thermal storage stability, and the construction reserve time satisfied industry requirements. The EMPU-modified asphalt binder exhibited excellent high- and low-temperature rheological properties. Moreover, it demonstrated a more balanced performance than EP- and PU-modified asphalt binders. The EMPU-modified asphalt binder had economic and environmental advantages and can be considered a candidate material for the steel bridge deck pavement. A further investigation of its properties and mechanisms will be conducted in future research.