MICROMECHANICAL MODELLING OF FRACTURE PROCESSES IN CEMENT COMPOSITES

摘要

Cement composites are the most popular and widely used construction material in the world.Understanding and predicting fracture processes in these materials is scientifically challenging but important for durability assessments and life extension decisions.A recently proposed microstructure-informed site-bond model with elastic-brittle spring bundles is developed further to predict the elastic properties and fracture process of cement paste.It accounts for microstructure characteristics obtained from high resolution X-ray computed microtomography (micro-CT).Volume fraction and size distribution of anhydrous cement grains are used to determine the model length scale and pore-less elasticity.Porosity and pore size distribution are used for tuning elastic and failure properties of individual bonds.The fracture process is simulated by consecutive removal of bonds subject to failure criterion.The stress-strain response and elastic properties of cement paste are obtained.The simulated Young's modulus and deformation response prior to peak stress agree very well with the experimental data.The proposed model provides an effective tool to simulate micro-cracks initiation, propagation, coalescence and localization.