A Numerical Method For Predicting The Elastic Modulus Of Lightweight Aggregate Concrete

Lightweight aggregate concrete is a kind of concrete made with lightweight aggregate and cement and has widely been used in various engineering structures.As an important parameter for evaluating the stiffness of concrete structures,the elastic modulus has been the focus of research of scholars at home and abroad.The investigation into the quantitative relationship between the macro scopical elastic modulus and the mesostructure of lightweight aggregate concrete through numerical methods is of higher theoretical significance and application value for further understanding the mechanical properties of lightweight aggregate concrete.This paper presents a fast Fourier transform method for predicting the elastic modulus of lightweight aggregate concrete.Light aggregates are modeled as ellipses and polygons,the periodic boundary conditions are introduced,and the mesostructure of lightweight aggregate concrete is reconstructed in a square simulation element.With grid division and selection of equal-distance pixels,the fast Fourier transform method is used to analyze the elastic modulus of two-dimensional nonhomogeneous materials.The reconstructed mesostructure of lightweight aggregate concrete with elliptical and polygonal lightweight aggregates is combined with the fast Fourier transform method to compute the elastic modulus of lightweight aggregate concrete.Compared with the experimental results obtained from the literature,it is confirmed that the numerical method is of higher accuracy.Based on the principles of the Monte-Carlo numerical integration,the interfacial transition zone area fraction in lightweight aggregate concrete with polygonal aggregates is calculated and the main influential factors are analyzed quantitatively.At the same time,based on the numerical results,the main factors that affect the elastic modulus of lightweight aggregate concrete are analyzed in a quantitative manner.