@article {525, title = {A reaction model for cement solidification: Evolving the C{\textendash}S{\textendash}H packing density at the micrometer-scale}, journal = {Journal of the Mechanics and Physics of Solids}, volume = {118}, year = {2018}, month = {Sep-2018}, pages = {58 - 73}, abstract = {
Cement paste is a multiphase material of complex chemistry, of which 60\% by volume is typically composed of calcium\–silicate\–hydrates (C\–S\–H), the phase that lends the material its strength and stiffness. Moreover, it has been shown that the C\–S\–H phase is a dispersion of nanometer-sized particles that are characterized by an attractive\–repulsive potential and densify in course of the hydration reaction. Herein, we model the nucleation and growth of the nanoparticles as a continuous density field subject to a reaction equation. Using this phase-field approach, we aim to reduce the parameter space present in similar hydration models and create a vehicle to upscale mechanical information from the nanometer-scale to the micrometer-scale. Despite the apparent simplification of the physics at play, we readily reproduce the cement paste reaction kinetics and microtexture\—functions of temperature, coarseness of the calcium\–silicate source particles, and initial water-to-cement ratio\—, and vet them against experimental observations. Presenting results for two-dimensional simulations, we achieve excellent agreement with measurements of hydration heat curves, pore-chord-length and solid-chord-length density functions, distributions of low- and high-density C\–S\–H products, and elasticity.