Micromechanical modeling of concrete response under static loading - Part 1: Model development and validation

A new micromechanical model has been developed that considers tensile crack ing as the only fracture criterion at the microlevel. The model utilizes th e finite element method as a numerical tool where the truss element is used as the basic element in the finite element mesh. The internal structure of concrete is considered as a three-phase material, viz. matrix, aggregate, and interfaces between the matrix and the aggregate phases. The model consi ders the randomness of the aggregate phase, as well as the probabilistic na ture of the properties of the three phases. The constitutive relations of t he elements for all phases at the microlevel are described according to the smeared cracking concept that is based on the fictitious crack model. The proposed model is able to predict the complete mechanical response associat ed with different loading stages, localization of deformation, and the effe ct of size on nominal strength. Model predictions are in agreement with doc umented experimental work.