Effect of concrete mesostructure on its elastic modulus

At a mesoscopic level, concrete can be considered to be a three-phase composite material, composed of aggregate, interfacial transition zone (ITZ) and cement paste. As such, the mechanical behavior of concrete, such as elastic modulus, fracture energy and strength, is dependent on the proportions, mechanical properties and interaction of these three phases. The intention of the present paper is to study the effect of concrete mesostructure on its elastic modulus. By combining the mesostructural simulation method with the technique of Monte Carlo integral, a numerical algorithm for ITZ volume fraction is developed. Based on the algorithm, the effect of the ITZ thickness, largest aggregate diameter and aggregate gradation on ITZ volume fraction is discussed. Then, the finite element method is adopted to obtain the numerical solution of the elastic modulus of concrete. A comparison of the elastic modulus of concrete between the numerical and experimental results is drawn to demonstrate the effectiveness of the numerical method presented in this paper. Finally, a parametric study is conducted to investigate the effect of the largest aggregate diameters aggregate gradation, and characteristics of ITZ on the elastic modulus of concrete.