Abstract:
In order to make studies of unfavorable effects of the freezing and thawing cycles upon the dynamic properties of the concrete, the laboratory tests, which suffered 40% of
fc loading history of the concrete specimens after 0, 10, 25, 35 and 50 cycles of the freezing and thawing (
fc defined as the uniaxial compressive strength of the ordinary concrete) were carried out by a 10 MN large multi-purpose static and dynamic triaxial apparatus at a strain rate of 10
-4/s. The uniaxial compressive strength of the concrete under the action of the cyclic freezing and thawing was obtained, and the damage evolution law and failure mechanism were analyzed. The testing results show that the uniaxial compressive strength of the concrete decreased with the increase in the number of the freeze-thaw cycles, and the peak stress along with the change of the freeze-thaw cycles was characterized by a quadratic curve relationship. And from the testing results it is found that the validated Weibull-Lognormal segment type damage constitutive model can be well used for fitting the uniaxial stress-strain curves of the concrete deteriorated by the freeze-thaw cycle damages after the loading histories. In addition, the number of the freeze-thaw cycles of the concrete is more, the degree of damage to the concrete is greater, and in the later stages of damage development, the damage path of the concrete with a large degree of freezing and thawing is greatly prolonged and tends to flattening until it is in the damage stage.