Modelling of nano-silica in cement paste

摘要

Recently published experimental evidence shows that nano-silica is a material that can be used to enhance the strength and durability characteristics of concrete. Engineered concrete at the nano-scale is achieved through the integration of nano-materials in suitable proportions and relevant mixing methods. Being a pozzolanic and reactive material along with nucleation effects and miniature particle size, nano-silica has been found to significantly improve the micro-structural characteristics of concrete making it denser and more uniform. The ongoing research work at the University of Melbourne is based on a novel modelling approach to further investigate the performance characteristics of nano-silica on cement paste at the micro-meter scale. The volumetric proportions of different phases present in concrete are computed considering hydration characteristics of cement and those of nano-silica. A Representative Volume Element (RVE) of the cement paste at micro scale is developed considering the hydrated gel as the matrix material while other phases present are integrated as randomly distributed spherical particles. Constitutive material models for these phases are assumed. The stress-strain relationship for the RVE is then generated using COMSOL Multiphysics software. The approach proposed in this paper is an initiation towards developing an acute and compressive model to predict the performance characteristics of nano-engineered concrete.