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.2022 The Author(s). Published by Elsevier B.V.

Automated summary

Interfacial transition zones (ITZs) between cement paste and aggregates play a significant role in the mechanical characteristics of cementitious materials. This study focuses on the ITZ between calcium silicate hydrate (C-S-H) and silicon dioxide (SiO2) at the nanoscale and presents numerical modeling of the interface using molecular dynamics simulations. Uniaxial tensile tests were conducted to investigate the mechanical characteristics of the C-S-H-SiO2 systems with different ITZ thicknesses and strain rates. The simulations reveal that the thickness of the ITZ negatively affects the mechanical characteristics of the system. Additionally, increasing the ITZ thickness leads to a decrease in the mechanical characteristics of the system. This study contributes to a better understanding of the influencing mechanism of ITZ thickness and strain rate on the mechanical characteristics of composite C-S-H-SiO2 systems.