N-Phase micromechanical framework for the conductivity and elastic modulus of particulate composites: Design to microencapsulated phase change materials (MPCMs)-cementitious composites

Abstract

The smart design of microencapsulated phase change materials (MPCMs) in cementitious composites requires an explicit understanding of effects of soft microcapsule particles, stiff aggregates and their surrounding weak interfaces on the physico-mechanical properties of particulate composites. This paper devises a n-phase micromechanical framework to predict the effective thermal conductivity and elastic modulus of multicomponent particulate composites that consist in stiff and soft anisotropic-shaped inclusions, their surrounding weak interfaces and matrix. In this micromechanical model, the volume fraction of weak interfaces treated as the interphase model is quantified and incorporated into the n-phase differential effective medium model. It is found that the structural configuration of interfaces has a significant effect on the effective physico-mechanical properties of particulate composites. The micromechanical model leads to predictions of the effective conductivity and elastic modulus of multicomponent particulate composites to a good accuracy by comparing with available experimental data for regular concrete, quartz mortar and MPCMs-cementitious composites. By utilizing the micromechanical model, the authors further develop a theoretical design rule for the robust overall performance of MPCMs-cementitious composites with the better thermal resistance and elastic modulus. These results can also be used to design other multiphase particulate composites and porous media with the cherry-pit structure.