Study On The Relationship Between The Lab And Natural Conditions Of Hydraulic Structure Concrete Freezing And Thawing

In the cold regions of China, the damage of hydraulic structures is affected by freeze-thaw cycles. According to the operating environment of the hydraulic structure, there are some differences in the Structure freeze thaw environment. At present, rapid freezing and thawing test and CDF are primary methods to design the frost resistance. But the freezing and thawing cycles of concrete in laboratory are not directly related to that in practical engineering. Therefore, it is important to establish the relationship between freezing and thawing cycles of concrete structure and test specimen.Through sampling and testing, we establish the relationship between freezing and thawing cycles of concrete structure and test specimen to solve the damage of hydraulic structures is affected by freeze-thaw cycles.First, the Song Tun reservoir to take the experience of 37 years of freezing and thawing concrete specimens. The test pieces were carried on the dynamic modulus and ultrasonic testing.Secondly, determine the concrete mix ratio, the preparation of the intensity of C20 and C25, the amount of fly ash was 0%, 20%, 0% and 3% silica fume concrete specimens respectively; rapid freeze-thaw and CDF. The test results show that: in addition to C20 concrete, 310 times of rapid freezing and thawing cycles, the relative mass loss rate of concrete specimen is lower than 5%, the relative dynamic modulus is above 60%, the ultrasonic velocity is above 85%. After 28 cycles of CDF, quality loss per square meter is less than 700g/m2, and the ultrasonic relative dynamic modulus is above 88%, meet the specification value.Finally, MATLAB software is used to analyze the dynamic elastic modulus and ultrasonic wave velocity test data. The relationship between the number of freeze-thaw cycles and the ultrasonic wave velocity is established. The relationship between the results of the model is different from that of other people. It can predict the number of cycles of concrete in the actual engineering environment, and then predict the life of concrete structures by using the freezing and thawing cycle parameters.