Study On The Influence Factors And Characterization Of Salt Alkali Environment On The Safety Of Concrete Structure

Xinjiang is located in the west of China.The land salinization is serious and the area of salinization covers a wide area.There are many kinds of ions such as-Cl 、2-4SO 、-OH 、(10)Na 、(10)K etc.in the saline alkali environment,the concrete exposed to salt and alkali environment is easy to be eroded by the above-mentioned ions,the corrosion products make the concrete expand and crack,and the ions diffuse into the concrete through the cracks further,which aggravates the corrosion degree of the reinforcement,and finally forms a vicious corrosion cycle,which makes the reinforcement lose its bearing capacity completely,and seriously affects the safety of the concrete structure.In order to improve the safety factor of buildings,advanced physical and chemical means should be used to detect the concrete bearing capacity in the early stage of reducing,evaluate the "healthy state" of concrete structure,and estimate its remaining life.In the existing detection methods,the ultrasonic detection method can only be used to detect the position of the reinforcement in the structure,the chemical analysis method will cause damage to the concrete structure,the resistivity method will be affected by the reinforcement in the concrete,resulting in great errors in the detection results,and the detection results are not accurate.Therefore,this project starts from the study of the induced polarization effect inside the concrete,through the observation of the apparent polarizability of the concrete to effectively monitor the environment and temporal and spatial change rules of the internal medium corrosion and reinforcement corrosion of the concrete,so as to improve the accuracy of the concrete safety detection and monitoring.This paper mainly studies the influence factors and characterization of the salt alkali environment on the safety of concrete structure.First of all,according to the sampling results of Xinjiang saline alkali soil,the experiment of concrete saline alkali erosion is designed,and the concrete and reinforced concrete test blocks mixed with different saline alkali ions are constructed to imitate the local situation of concrete saline alkali erosion in Xinjiang.Secondly,aiming at the problem that it is difficult to apply half space or full space boundary value problems to analyze the internal electric field of concrete,the physical model test,image method and numerical simulation method are used to confirm each other,and the observation methods of electric field and polarizability of internal medium of concrete are studied.At the same time,the resistivity and polarizability of concrete and reinforced concrete specimens within 28 day curing period are measured by measuring the resistivity of rock specimens,and the corresponding relationship between the change of electrical parameters and ion,the change of electrical parameters andthe change of time are analyzed.Finally,the difference of electrical parameters between the test blocks is studied,the results show that it is feasible to use polarizability parameters to detect the corrosion of concrete by salt and alkali.