A nano-model for micromechanics-based elasticity prediction of hardened cement paste

Abstract

Micromechanics-based elasticity prediction of cement paste has been studied for nearly a decade. Existing models are all based on previous knowledge of the microstructure of cement paste and usually ignore the morphological effect of the inclusions. This paper develops an equivalent-individual inclusions model for elasticity prediction of hardened cement paste with consideration of the microstructural variation given a low water-to-cement ratio condition and the non-spherical morphology of the inclusions. High-density calcium silicate hydrate, ultra-high-density calcium silicate hydrate and cement clinker are together modelled as the equivalent inclusion, while calcium hydroxide and capillary pores are modelled as individual inclusions embedded in the low-density calcium silicate hydrate matrix. The equivalent inclusion and calcium hydroxide are presented as spheroids with different aspect ratios. The elasticity values of hardened cement paste are then obtained through a five-step calculation flowchart based on the Mori–Tanaka scheme. Finally, predictions of the equivalent-individual inclusions model are compared with experimental data and the validity of the model is verified. The paper concludes that, when the water to cement ratio is in the range of 0·25–0·6, the equivalent-individual inclusions model can predict the elasticity of hardened cement paste with an average error smaller than 4%.