Hydrating Cement Particle Interaction Model for Yield Stress Analysis

This study overviews existing methods for analyzing cement paste yield stress, and presents a new approach based on micro-structural computation. The proposed model explicitly considers cement particle interactions, both the colloidal and the nucleated gel ones. A new algorithm is proposed based on flocculating of poly-dispersed hard spheres in a simulation box, followed by nucleation of mono-sized nano-gel particles. The obtained virtual microstructures are than used as an input for a mechanical approach, which is conceptualized for simulating sliding kinematics needed to initiate the flow of the percolated solid network, i.e. to reach the paste yield stress. The microstructural modeling tool provides insights on how the localized gel is bridging the cement particles, responsible for the yield stress properties of bulk cement paste. Thus, it provides a promising new approach for quantifying the evolution of the bridging strength with nucleation (shear rest) time, enabling parametrization of the mechanical yield stress computation at micro-structural scale.