Tensile strength of calcite/HMWM and silica/HMWM interfaces: A Molecular Dynamics analysis

The mechanical behavior of interfaces between high molecular weight methacrylate (HMWM) and concrete minerals (calcite and silica) is investigated from a Molecular Dynamics (MD) perspective. MD simulations of pullout tests shows that interfaces debond at the surface of contact between HMWM and the mineral substrate, and that the interfacial strength decreases in the presence of moisture, under low strain rate, or at high temperature. Silica/HMWM interfaces are stronger than the calcite/HMWM interfaces. Additionally, the work of separation is mostly done by van der Waals forces, in agreement with previous studies. We use published experimental data at low strain rate along with our MD results at high strain rate to calibrate Richeton's model and Johnson-Cook model. We show that, if more experimental results were available for validation, MD results could be extrapolated to predict the tensile modulus of HMWM at low strain rate and the HMWM/mineral interfacial strength for a broad range of temperatures and strain rates. The sensitivity analysis of the model confirms that HMWM should be applied on dry surfaces and in concrete exposed to lower temperatures. Additionally, MD results suggest that HMWM is more likely to last in concrete with high silica contents than in concrete with high calcite contents. (C) 2020 Elsevier Ltd. All rights reserved.