Analysis of hygral induced crack growth in multiphase materials

In this paper a numerical model for simulating crack growth processes caused by moisture movement in a porous multiphase material like concrete is proposed. In the model, the material is schematized as a regular triangular network of beam elements. The meso-material structure of the material is projected on top of the lattice and different properties are assigned to the different phases. In the hygral analysis the lattice elements are considered conductive pipes. In the mechanical analysis, the lattice elements are beams which are characterised by a modulus of elasticity, Poisson's ratio, tensile strength and fracture energy. In contrast to the previously developed lattice model by Schlangen & Van Mier 1992, a softening relationship was used in the fracture analysis. Examples of shrinkage cracking in normal concrete containing dense natural aggregates and in lightweight concrete containing low modulus impermeable aggregate particles are given. Moreover, a comparison between a continuum based hygrall mechanical approach and the lattice type model is presented. The model seems a useful tool for estimating the effect of hygral shrinkage cracking on the mechanical properties of concrete.Stevin laboratoryCivil Engineering and Geoscience