Effects of emulsified asphalt on the rheological behaviors of magnesium phosphate cement

The traditional method for repairing asphalt pavement relies on hot-mix asphalt. Owing to its high energy consumption, this method proves inadequate in meeting the growing demands of low-carbon and environmental protection. Further, the utilization of cold-patching material is limited due to its slow strength development and poor long-term durability. Therefore, in this study, an organic–inorganic composite system that is based on the addition of emulsified asphalt and magnesium phosphate cement (MPC-EA) for filling asphalt pavement cracks was developed. Since the rheological properties of the slurry play a crucial role in determining its suitability for injection into the area to be reinforced and the effectiveness of crack repair, the effect of EA content on rheological properties was investigated. Specifically, the rheological properties of the slurry were analyzed at 260 s, and the rise in hydration temperature during this period was monitored to better understand the hydration process. The addition of EA drastically influenced the shear thickening of the original MPC system, and the rheological parameters changed with an increase in the EA content (10%–40%). The rheological loss mechanism of the composite system was elucidated by studying the hydration temperature and rheological parameters of the MPC-EA composite system. Further, an early rheological model of the composite system was established to understand the interaction mechanism of the MPC-EA composite system, and a constitutive equation of MPC-EA that considers the influence of EA content was devised. This study provides valuable information that can facilitate the field application of novel repair materials for pavement crack repair.