Prediction Of The Elastic Moduli Of Cement-Based Materials

It is well known that, due to the effect of the aggregate surface on the distribution of cement particles, a special structure, called the interfacial transition zone (ITZ), is formed between the aggregates and cement paste of concrete. Due to the ITZ, concrete can be considered as a three-phase composite material, consisting of aggregates, cement matrix and ITZ. As such, the macroscopic properties of concrete are dependent on the volume fractions, elastic moduli, and interaction of the three phases to a great extent. Therefore, the study of the elastic modulus of hardened cement paste and the effect of inhomogeneity of ITZ on the elastic modulus of concrete is of important theoretical and practical significance to further understanding the macroscopic physicomechanical behavior of concrete.A method is presented in this paper for predicting the elastic moduli of hardened cement paste and concrete with inhomogeneous ITZ. Based on the exact solution for the elastic modulus of two-phase composite materials, a multi-level simulation method is presented for predicting the elastic modulus of hardened cement paste. The validity of the proposed method is preliminarily verified with the experimental results obtained from the literature. An analytical method is presented for predicting the elastic modulus of concrete with inhomogeneous ITZ. By comparing with the experimental results collected from the literature, the validity of the proposed method is verified. Based on further numerical analyses, the effects of the maximum aggregate diameter, the water/cement ratio, the maximum cement diameter, and the aggregate gradation on the elastic modulus of concrete are discussed in a quantitative manner.