Design And Preparation Of Repair Structure For Concrete Surface Powdering Disease In Severe Cold Area

Concrete is the most popular building material all around the world and plays a important role in modern construction.However,concrete has its inherent disadvantages.For example,the structure disease of concrete caused by durability problem is the major problem for application of concrete materials and eventually leads to the failure of concrete structure.Through the research on the repair work of concrete in Shengyang,this paper has reached the following conclusions.(1)The disease degree and the appearance characteristics of the concrete were analyzed by site survey.Through the study of mechanical properties and freeze-thaw durability of core-drilling sample,the disease mechanism of the concrete were analyzed.And by SEM analysis,it was determined that the main mechanism of concrete disease is freeze-thaw damage.(2)A multi-gradient composite repair structure was designed for the disease concrete.The repair structure is mainly composed of repair material layer and composite material layer.The structure can reinforce the concrete and prevent entrance of the external aggressive medium.The repaired structure is proved to have good repair function and durability.(3)Based on the design of the repair structure,the preparation technology was discussed.The repair structure has the good durability and good compatibility with disease concrete.(4)Through the study of the bond strength between repair material to composite material and repair material to disease concrete,the construction technology of the repair structure was discussed.It was found that the treatment of fiber material with pre-impregnated slurry can significantly increase the bond strength between repair materials to composite material.Good interface treatment and suitable interface agent can enhance the bond behavior between repair materials to concrete.