The pre-crack method was used to simulate the cracked concrete in the actual engineering. The damage degradation process and mechanical properties of the concrete with cracks under freeze-thaw cycles were studied. Through the observation of surface change, uniaxial compression and elastic modulus test of concrete specimens with and without pre-crack to study the freeze-thaw cycles effected on the elastic modulus, axial compressive strength, stress-strain relationship of specimens with and without pre-crack, the relationship between peak stress and peak strain as a function of freeze-thaw cycles was obtained. Combined with the damage mechanics, the effects of pre-formed cracks on the frost resistance of concrete were analyzed. The results showed that, after freezing and thawing, the crack-free specimens appeared flaking of surface and corner cutted. The phenomenon of radial propagation of pre-cracks and lateral initiation of transverse cracks appeared in pre-crack specimens. The loss rate of strength and modulus of elasticity of precast cracked concrete specimens were faster. The formulas for calculating peak stress and freeze-thaw cycles of pre-crack specimens were obtained. The cracks caused the concrete damage rate to be greater than that of the specimens without pre-crack.
WITTMANN F H, WANG P, ZHANG P, et al. Capillary Absorption and Chloride Penetration into Neat and Water Repellent SHCC Under Imposed Strain[C]//2nd Int. RILEM Conf. on Strain Hardening Cementitious Composites, Rio de Janeiro. 2011(1):165-172.
CHENG Y, ZHANG Y, JIAO Y, et al. Quantitative Analysis of Concrete Property Under Effects of Crack, Freeze-Thaw and Carbonation[J]. Construction and Building Materials, 2016(129):106-115.
WARDEH G, GHORBEL E. Prediction of Fracture Parameters and Strain-Softening Behavior of Concrete:Effect of Frost Action[J]. Materials&Structures, 2015,48(1-2):123-138.