Concrete Performance Test Under Salt Freezing And Dynamic Parameters Analysis Of Continuous Beam Considering Its Influencing

Concrete salt freezing is actually the coupling effect of freeze thawing and salt erosion, due to the promoting effect of the two effects which will lead to damage caused by concrete freeze-thaw more serious than that by freeze thawing and salt erosion alone. In the cold area, spreading ice salt is often used to remove snow from the bridge area, which leads to the destruction of the concrete bridge. There are many factors that affect the frost resistance of concrete, and the mechanism of salt freezing damage is very complicated. At present, the study on the mechanism of concrete salt freezing damage has just started, and has not formed a theoretical system. Bridge dynamic parameters are often applied to bridge structural damage identification and condition assessment. How to calculate the dynamic parameters of the bridge structure concrete after being subjected to salt freezing is of great important.In this paper, the research on Concrete performance test under salt freezing and dynamic parameters analysis of continuous beam considering its influencing is carried out, and the main research work is as follows:1. The salt freezing diseases of 523 highway bridges and 170 common highway bridges in Jilin province were investigated, the mechanism of salt freezing damage of concrete bridges was discussed based on the investigation results.2. Because there are many factors that affect the frost resistance of concrete and the influence of these factors on the frost resistance of concrete is mutual coupling, this is not conducive to the effect of single factor on the salt resistance of concrete. The authors put forward the influence of some parameters on the frost resistance of concrete by using salt freezing test of cement mortar. On the basis of salt freezing test of cement mortar, the effect of chlorine salt solubility and mineral admixture on the salt resistance of concrete was discussed.3. The mass loss and relative dynamic elastic modulus of concrete specimens with 15% fly ash were tested, and this paper has the fitting analysis on the test data to obtain the effect of salt freezing on the basic calculation parameters of concrete bridge dynamic parameters. Based on the influence law and the basic principle of vibration of beam structures, the calculation method of dynamic parameters of continuous concrete beams after salt freezing damage was formed. Finally, the dynamic parameters calculation method is applied to the numerical simulation of a two span continuous beam, and the influence of the salt damage on the dynamic parameters of the continuous beam is discussed.