Research On Durability And Grouting Effect Of Concrete Structure After Crack Repair In Corrosive Environment

Reinforced concrete structure is the most widely used structural form in people’s production and life,but the concrete material itself has low tensile strength,and cracks generally exist during normal use.In a corrosive environment,cracked concrete structures face severe durability degradation problems.The traditional crack grouting repair method can effectively seal cracks and is widely used in different engineering fields.However,the research on the recovery performance of the durability performance of reinforced concrete structures after grouting repair is lacking.At the same time,the depth of the grouting repair is the key to the effective protection of the steel bars in the structure,but the actual construction quality in the project is mostly controlled by experience,the grouting effect is uneven,and the secondary cracking occurs frequently after repair,and still has many processes and small scope The destructive testing method is used as the acceptance standard.Based on this,this paper conducts an experimental study on the uncertainty of durability of concrete structure cracks after grouting repair in a corrosive environment.At the same time,based on ultrasonic detection technology,the nondestructive testing method of grouting repair effect is explored,and the technology of existing grouting repair methods for optimization,the main research contents are as follows:(1)Make test pieces with different crack widths,and use different grouting materials to repair the cracks,simulate the deterioration process of concrete structure in real corrosion environment by electromigration chloride ion combined with dry and wet cycle test,and monitor the dry and wet cycle with electrochemical test method During the process,the electrochemical parameters of the steel bar were changed.According to the corrosion electrochemical theory,the corrosion behavior of the steel bar in the repaired concrete was evaluated.The durability of the grouting repair under different materials and crack widths was studied.The test results show that the long-term durability of the polyurethane chemical grouting process that only meets the requirements of water plugging in a corrosive environment cannot meet the requirements.The durability of the concrete structure after the epoxy resin chemical grouting process can be restored to the level of no cracks.The following chemical grouting process selection and durability evaluation are of guiding significance.(2)Based on the ultrasonic detection technology,the grouting effect of specimens with different crack widths is tested,and the ultrasonic first-wave amplitude,acoustic time value and other acoustic characteristics during the grouting repair process are analyzed to determine the coverage of the slurry by comparing the ultrasonic acoustic parameters.The slurry coverage on the actual fracture surface proved the relationship between the ultrasonic characteristic value and the grouting depth.The results show that the ultrasonic first-wave amplitude of the effective repair area after crack grouting is significantly improved compared with that before grouting,and the acoustic time value is reduced.The coverage of chemical grouting can be obtained by analyzing the ultrasonic eigenvalues,so as to detect and evaluate cracks.(3)Through analysis of the engineering drilling grouting process,the borehole spacing,drilling depth and slurry amount in the grouting process were selected to optimize the design of the optimized grouting test,and from the perspective of durability guarantee,explore the factors to repair the grouting Effect impact.The results show that shortening the borehole spacing and increasing the borehole depth help to improve the grouting effect.Among them,the borehole depth is the key factor of the grouting limit coverage depth value,and the corresponding process requirements are proposed based on the durability index requirements.