A nanoscale numerical model of calcium silicate hydrate

This manuscript presents a numerical model of the low-density and high-density calcium–silicate–hydrate (C–S–H) gel phases in cement paste. Generated using an autocatalytic growth algorithm, C–S–H is introduced as an assemblage of discrete granular particles at nanoscale with realistic particle-level properties, such as elastic modulus, friction, and cohesion. Using the discrete element method, nanoindentation simulations are performed on each phase, demonstrating that its mechanical contact properties compare well to the results from nanoindentation experiments in the literature. By creating an additional loosely packed phase of C–S–H and maintaining constant particle-level material properties, the results further show that the indentation modulus, as a function of the volumetric packing fraction of the C–S–H gel phase, compares well to a linear self-consistent scaling relation while the hardness most closely fits a nonlinear self-consistent scaling relation.

► We numerically model calcium silicate hydrate gel in cement paste.
► The model consists of discrete cohesive-frictional nanoscale particles.
► Bulk properties determined by indendation simulations compare well with experimental results.
► The indentation modulus versus volumetric packing density demonstrates a linear self-consistent scaling relation.
► The hardness compares well to a non-linear self-consistent scaling relation.