Molecular dynamics simulation study on dynamic mechanical properties of C-S-H with diverse Ca/Si ratios

Ca/Si ratios and strain rates significantly affect the properties of calcium silicate hydrate (C-S-H), which dominates the mechanical characteristics of concrete composites. Consequently, it is necessary to reveal the influence of Ca/Si ratios and strain rates on the mechanical characteristics of C-S-H. In this paper, considering the scope of the Ca/Si ratio of C-S-H, model constructions with diverse Ca/Si ratios (Ca/Si = 1.24, 1.41, 1.64, 1.80) were performed. Various strain rates with values of 0.1 ps−1, 0.01 ps−1, and 0.001 ps−1 in the x, y and z directions were designed in uniaxial tensile tests by molecular dynamics simulations. The simulations demonstrate that the Young`s moduli and peak stresses of C-S-H increase with rising strain rates and decrease resulting from the increasing Ca/Si ratios. This research uncovers the influence of diverse Ca/Si ratios and various strain rates on C-S-H from molecular insight. This research improves the understanding of the influence mechanism of Ca/Si ratio and strain rate on the mechanical properties of C-S-H.