Study on Strengthening Mechanism of Epoxy Resin/Rubber Concrete Interface by Molecular Dynamics Simulation

Rubber concrete has high environmental and economic benefits. However, the difference in the physical and chemical properties of the interface causes a weak interface between rubber and concrete, which limits the use of rubber concrete to a certain extent. Based on the macroexperiment of epoxy resin (EP) modified rubber concrete, from the nanoscale level, three interface models of Rh (natural rubber)/C-S-H, EP/C-S-H, and Rh/EP/C-S-H were constructed by molecular dynamics simulation to explore the interaction between epoxy resin and rubber cement-based interface and reveal its microreinforcement mechanism. The results of interaction energy, radial distribution function, and mean square displacement show that the addition of EP not only improves the interface interaction energy between Rh and C-S-H but also provides a large number of hydrogen bond donors and receptors, promotes the diffusion of Ca, and increases the adhesion between Rh and cement matrix. The results of the analysis of mechanical properties show that the elastic modulus of the rubber concrete interface model is improved and the interface properties are improved after adding EP.