A microstructure-based model for quantifying irreversible yield stress evolution in cement-based pastes during hydration

Investigating workability loss in cement-based pastes during hydration, primarily marked by an irreversible yield stress increase, is crucial for cement-based materials application and development. This paper presents a model for quantifying the irreversible yield stress evolution by incorporating microstructural changes involving physical, chemical, and physicochemical effects. By systematically integrating solid volume and cement interparticle forces, including van der Waals forces and ionic correlation forces from C -S -H bridges, the model is formulated and then validated against experimental results. The relative contribution of interparticle forces and solid volume, as well as polycarboxylate (PCE) superplasticizers impact on yield stress is explored. The results indicate the model effectively captures microstructural changes and predicts the yield stress increase predominantly driven by interparticle forces. Notably, the PCE superplasticizer dosage significantly reduces yield stress, potentially to 0 Pa at saturation plateau. This study provides a comprehensive, quantitative understanding of irreversible yield stress evolution in cement-based paste.