Creep of Bulk C--S--H: Insights from Molecular Dynamics Simulations

TL;DR

This study uses molecular dynamics simulations to investigate the long-term creep behavior of calcium-silicate-hydrate (C--S--H), revealing a logarithmic strain increase and a stress-independent creep modulus consistent with experimental data.

Contribution

Introduces a novel molecular dynamics method to simulate and analyze the visco-elastic creep behavior of C--S--H at long timescales.

Findings

C--S--H exhibits logarithmic shear strain increase under stress.

Creep modulus is independent of applied shear stress.

Simulation results agree with nanoindentation measurements.

Abstract

Understanding the physical origin of creep in calcium--silicate--hydrate (C--S--H) is of primary importance, both for fundamental and practical interest. Here, we present a new method, based on molecular dynamics simulation, allowing us to simulate the long-term visco-elastic deformations of C--S--H. Under a given shear stress, C--S--H features a gradually increasing shear strain, which follows a logarithmic law. The computed creep modulus is found to be independent of the shear stress applied and is in excellent agreement with nanoindentation measurements, as extrapolated to zero porosity.