Integrating Physicochemical and Geochemical Aspects for Development of a Multi-scale Modelling Framework to Performance Assessment of Cementitious Materials

Abstract

A robust and reliable model has been required to take into account the fundamental physicochemical and geochemical reactions resulting due to detrimental effects during the service-life of concrete structures. A multi-scale model developed by Concrete Laboratory at the University of Tokyo is extended in this study by coupling geochemical code PHREEQC with the model. The newly developed multi-scale modelling framework capable of addressing physiochemical and geochemical processes in cementitious materials such as hydration of cement particles, pore structure formation, multi-species transport, activity effect, ionic interaction with cement hydrates, etc. In addition, it provides a better understanding of the underlying mechanisms, which govern the degradation of cementitious materials. The model predictions for composition of cement hydrates and porosity are quantitatively compared with experimental results obtained in the literature. The capability of the model in evaluating the performance of cementitious materials in various aggressive environments is addressed. The simulation results predict the spatial and time variation of solid phases, pore water compositions, pore structure properties, etc. Thus the developed multi-scale framework can potentially be applied to assess long-term durability of concrete infrastructures.