A numerical investigation of the effect of the interfacial zone in concrete mixtures under uniaxial compression the case of the dilute limit

A two-dimensional numerical investigation concerning the effects of the interfacial transition zone (ITZ) on the mechanical behavior of concrete is presented in this paper. The ITZ lies between the cement paste and the aggregates. Considering elastic two-dimensional models of the cement paste, the aggregate material and the ITZ, which is modeled as a thin band around each grain of aggregate, the response of the composite material was calculated using the finite element method. A parametric analysis was conducted for different model geometries as well as varying model parameters for the dilute limit, i.e. when the aggregate volume fraction is very small. Results indicate that the maximum tensile stresses which could lead to the development of microcracks, as well as larger displacements, tend to develop mainly in the ITZ. The distribution of stresses and displacements along appropriate sections of these models are also presented.