Mechanical properties of interface between C–S–H and silicon dioxide: Molecular dynamics simulations

Interfacial transition zones (ITZs) between cement paste and aggregates is of great significance for the mechanical characteristics of cementitious materials. The interface between calcium silicate hydrate (C–S–H) and silicon dioxide (SiO2) was simplified as ITZs at the nanoscale, and numerical modeling of the interface was presented based on molecular dynamics simulations in this study. Uniaxial tensile tests with diverse ITZ thicknesses and strain rates were conducted to study the mechanical characteristics of the C–S–H–SiO2 systems. The simulations demonstrate that the thickness of the ITZ has a negative effect on the mechanical characteristics of the system. On the other hand, the mechanical characteristics of the system decrease resulting from the increasing thickness of the ITZ. From the point of view of the atomic scale, the current study contributes to understanding the influencing mechanism of ITZ thickness and strain rate on the mechanical characteristics of composite C–S–H–SiO2 systems.