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The paper deals with a pilot study focused on the freeze-thaw (F-T) resistance of concrete. A non-traditional approach to the evaluation of the F-T resistance of concrete based on the determination of the fracture parameters is presented in the paper. Three types of specimens were used in the experimental program – prisms with edge and Chevron notch, and cylinders with the Chevron notch. Three sets of specimens of each shape were tested in total. The reference set was stored in the water until the time of testing. Another two sets of specimens were subjected to 50 and 100 freeze-thaw tests, respectively. One F-T cycle consisted of 4 hours freezing in the air at temperature -18 °C and 2 hours thawing in the water at temperature +20 °C. Based on the results, it can be stated that the values of fracture energy are proportional to the area of the ligament. This finding was observed for all tested sets – non-frost and frost attacked. The values of modulus of elasticity and fracture toughness are influenced more by the geometry and also by the changes of the specimens’ stiffness due to the exposition to the F-T cycles.

In this work, a homogenization-based approach considering elastoplastic behavior and fracture process is proposed in order to investigate the micromechanical behavior of ductile porous materials. The material microstructure is represented by a representative volume element composed of elastic inclusions or porous placed inside the matrix. For modeling the interface zone, a contact finite element is developed as well as a cohesive fracture model in order to capture the effects of phase debonding, interface crack closure or opening, and the cracking process inside the matrix. Besides, the matrix behavior is governed by the Von Mises elastoplastic model with linear strain hardening. Some numerical examples are analyzed in order to showthat the proposed modeling is a suitable tool for the identification of constitutive responses of composite microstructures. [ABSTRACT FROM AUTHOR]