The Role of Water on C-S-H Gel Shear Strength Studied by Molecular Dynamics Simulations

The properties of the cement paste are defined to a high extend by those of the C-S-H gel, and irreversible deformations such as creep and shrinkage are not an exception. It is believed that molecular scale processes play an important role on the stress accumulation and relaxation, and molecular dynamics simulation a great tool to identify and quantify those mechanisms. In this work, we use NEMD simulation to investigate first the effect of the temperature and shear rate on the shear strength, Then, we study the stress development on a C-S-H interface with an increasing distance between adjacent particles. We discuss the results in terms of water, and we define a limiting distance, 1 nm, at which the shear strength is lost.