Numerical study on drying shrinkage of concrete affected by aggregate size

Abstract

This paper describes new insights on the influence of aggregate size on drying shrinkage of concrete through numerical simulation. Using a two-dimensional finite element method, it is demonstrated that it is impossible to reproduce the impact of aggregate size on concrete drying shrinkage by simply considering crack opening in the mortar matrix. From this result, it is deduced that the effect of aggregate size on concrete shrinkage is influenced by aggregate surface area. The application of a constitutive law that considers the characteristics of ITZ to coarse aggregate elements successfully reproduced the damage and shrinkage strain of concretes with different aggregate sizes. A certain range of virtual ITZ pore thickness in the model was found to allow simulation of the real phenomenon. It is concluded that ITZ characteristics should be taken into account when considering aggregate behavior in drying concrete.