Quantitative evaluation of elastic modulus of concrete with nanoidentation and homogenization method

This paper aims to evaluate the elastic modulus of concrete with nanoidentation technique and homogenization method. In this paper, concrete is divided into two parts: coarse pore and matrix. It is assumed that matrix is composed of five phases: stone aggregate, ITZ-1 (interfacial transition zone around stone aggregate), sand, ITZ-2 (interfacial transition zone around sand) and paste. Based on the Ca/Si ratio change in interface region, the thicknesses of interfacial transition zone around stone and sand were determined, respectively. The elastic moduli of stone, ITZ-1, sand, ITZ-2 and paste were determined by nanoidentation technique. The volume fraction of each phase was determined by Lu & Torquato model. The elastic modulus of matrix was calculated by Self-Consistent Method. Then, combining with the porosity of coarse pore determined by hardened concrete pore structure analyzer, the elastic modulus of concrete could be obtained by Mori-Tanaka method. Through comparison, it is found that the error between the theoretical calculation value and the macroscopic test value is within 10%. Therefore, the effectiveness of theoretical prediction model proposed in this paper was verified. (C) 2019 Elsevier Ltd. All rights reserved.