Journal of the American Ceramic Society 2018-04-10

Creep and Relaxation of Cement Paste Caused by Stress‐induced Dissolution of Hydrated Solid Components

Xiaodan Li; Zachary C. Grasley; Jeffrey W. Bullard; Pan Feng

Index: 10.1111/jace.15587

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Abstract

The creep and relaxation of cement paste caused by dissolving solid hydration products is evaluated in this work. According to the second law of thermodynamics, dissolution or precipitation of solid constituents may be altered by the change of stress/strain fields inside cement paste via alteration of the stress power or strain energy. Thus, it is hypothesized that stress‐induced dissolution can affect the overall creep/relaxation behavior of cement composites. A novel, fully coupled thermodynamic, mechanical, and microstructural model (TM2) that uses the finite element method was developed to predict the time‐evolving properties of cement paste under prescribed strains and to test the hypothesis. In the model, the strain energy was incorporated to accurately predict the effect of stress and strain fields on cement microstructure change. From the simulation results, depending on the stress/strain levels and the choice of the domain (over which the thermodynamic equilibrium is enforced), stress‐induced dissolution of solid constituents can lead to significant creep/relaxation.