Rheological and microstructural properties of foamed epoxy asphalt

Epoxy asphalt has been extensively used in the bridge deck pavement. The main concerns during the construction process of epoxy asphalt are including high construction temperature, high viscosity to deal with and limited construction time which finally affects the service performance of the pavement. In this study, foamed epoxy asphalt is proposed to solve these construction challenges. The foamed epoxy asphalt samples were prepared by foaming machine at different foaming water content in the laboratory. The viscosity-temperature performance, failure temperature, ZSV@60 °C, temperature sensitivity and storage stability were evaluated by rotational viscometer, temperature sweep, frequency sweep and storage tests. Fluorescence microscope and Infrared spectroscopy were utilized to characterize the morphology and chemical reaction change of non-foamed and foamed epoxy asphalt with different foaming water content. The results show that the addition of foaming water could improve the workability of foamed epoxy asphalt binder mixtures and prolong the allowable reserved time of construction process. Compared to non-foamed epoxy asphalt, foamed epoxy asphalt compromise failure temperature and viscosity@60 °C and improve the temperature sensitivity and storage stability. With the increase of foaming water content, the failure temperature, viscosity@60 °C and storage stability of foamed epoxy asphalt decrease at some extent, while the temperature sensitivity of foamed epoxy asphalt increases. According to the change of microstructure, the foaming water is beneficial to enhance the epoxy resin dispersion in the asphalt and promote the chemical reaction between epoxy resins and curing agent, which could improve the pavement performance of epoxy asphalt.