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Water reduces the stability and safety of paving material, and this has been extensively studied in traditional asphalt pavement. However, the influence of water on emerging cold-mixed epoxy asphalt (CEA) has not yet been acknowledged. In addition, the microstructure composed of epoxy resin (ER) and asphalt determines the performance of the CEA binder, and the influence of water entering this structure should be focused on. Here, CEA interfacial water models were established based on experimental and molecular dynamics (MD) simulations. The distribution and motion of the interfacial water and their influence on the energy, compatibility, and mechanical properties of CEA were explored. The results showed that CEA had desirable water stability when the water content was less than 5%. Water moved and was rearranged at the interface of the CEA and tended to move toward the ER. The water diffusion coefficient increased proportionally to the quadratic of the water content, and the structure of the CEA changed from an ordered short-range arrangement to a disordered one. Water reduced the interaction between the ER and asphalt by a maximum of 41.7% but had little effect on the compatibility of the CEA. Water plasticized CEA because the glass transition temperature of the CEA decreased, and less than 3% of water decreased the modulus of the CEA by a maximum of 27.0%. Simultaneously, water also destroyed the isotropy of the properties of the CEA. The gyration radius of the CEA dropped to approximately half of the value without water. This study is positive for promoting the performance improvement of CEA and provides a framework for studying CEA modeling and evaluation with MD simulations. [ABSTRACT FROM AUTHOR]

Cold-mixed epoxy asphalt (CEA) is an emerging energy-saving and environment-friendly material for steel bridge decks, overload roads, and airfield pavement. Occasionally, CEA suffers from impact with high strain rates, which will be extremely detrimental to the pavement's safety and stability. Since little research deals with this dynamic mechanical behavior, this study aims to clarify the dynamic mechanical performance of CEA mixtures (CEAM) under high strain rates. First, this study evaluated the quasi-static strength evolution by Marshall stability tests. The Marshall stability of CEAM more than quadrupled within the first 20 h and 1.6 times up again when exposed at 60°C, while its flow value showed the opposite trend. Then, the dynamic mechanical behavior under different high strain rates and temperatures was investigated by split Hopkinson pressure bar tests. Results showed that the peak strain rate (146–316 s−1) was 1.7–2.0 times greater than the average strain rate (84–162 s−1). The strain–stress curves became steep as the temperature and the pressure ascended. Under the same test conditions, the peak stress and the peak dynamic modulus of CEAM were 1.7 times larger than that of cement concrete. CEAM absorbed more energy below 25°C than 60°C. All the CEAM had binder failure, and the crushed specimens had aggregates broken. The constitutive model of CEAM was established based on the statistical damage theory and the modified Weibull distribution function. Besides, multiparametric regression analysis proved a demarcation point during the impact. [ABSTRACT FROM AUTHOR]