Multiscale simulation of mechanical properties and microstructure of CNT-reinforced cement-based composites

In the hydration process of a cementitious matrix, considerable interactive physical and chemical changes take place inside the material that affect both the composition and morphology of cement paste during its early stages. These changes are properly considered within a multiscale model that comprises length-scale integration and gives access to the effective properties via upscaling. In this paper, the kinetics laws of the induction period, nucleation, and growth-controlled and diffusion-controlled hydration are considered, and the evolutions of volume fractions of clinker phases and various hydration products with respect to the hydration degrees are simulated. Based on the microstructural evolution of cement hydration, the properties of cement paste are estimated with a combination of self-consistent and Mori-Tanaka schemes, and the mechanical properties of carbon nanotube-reinforced cement-based composites on the macroscale are then predicted with a meshless method on the basis of the moving least-squares approximation. Finally, the accuracy and efficiency of the proposed model are verified by comparisons with experiments and finite element model simulations. (C) 2017 Elsevier B.V. All rights reserved.