Multiple-inclusion model for the transport properties of porous composites considering coupled effects of pores and interphase around spheroidal particles

Abstract

Understanding of the effects of particle geometries, pores and interphase characteristics on transport properties of porous composites is very crucial to the smart design of porous composites and the improvement of their durability. In this work, the authors devise a multiple-inclusion micromechanical model to predict the effective transport properties of multiphase porous composites, where spheroidal inclusions of diverse types are randomly dispersed in a homogeneous matrix. The multiple-inclusion model is then applied to estimate the effective diffusivity of four-phase porous composites containing impermeable particles, pores, highly permeable interphase and matrix. Specifically, the microstructural characteristics of pores, interphase and particles, and their physical properties are incorporated into the evaluation of the effective diffusivity of porous composites. It is shown that the present model leads the prediction of diffusivity of porous composites to reasonable accuracy by comparing with extensive experimental data. Moreover, utilizing the proposed model, we investigate the dependence of effective diffusivity of porous composites on the shape, volume fraction and size distribution of impermeable particles, the interphase thickness and volume fraction, and the porosity characterized by the hydration degree of cement and the water-cement ratio. The results reveal that the geometrical and physical properties of these components play a significant role in determining the diffusivity of porous composites. The multiple-inclusion model provides a powerful and convenient predictive toolkit for multiphase composite design and evaluation.