Qingdao crack repairThree methods
Grooving to repair cracks
Grooving repair is a common method of crack plugging, and it is suitable for repairing cracks with a width greater than 0.5mm. Generally use epoxy resin: 10, polysulfide rubber: 3, cement: 12.5, sand: 28. First, mix the dried and sieved sand and cement evenly by hand, and then mix the epoxy polysulfide rubber in proportion. Then mix the well-mixed sand and cement, and then continue manual mixing. Finally, use a small amount of acetone (acetone about 0.4kg) to dilute the mixed mortar to a medium consistency. The mixed modified epoxy mortar should be put into the concrete chisel groove in time, cleaned and dried with a rubber cylinder, and then pre-embedded. From mortar mixing to pre-embedded concrete joints, the entire construction process of a group of mortars takes about 30 minutes to complete. Mortar curing after embedding refers to embedding the mortar in the tank and covering it with felt and sack within 2 hours after treatment. Water conservation begins after the initial setting. It should be noted that after chiseling the groove, it must be rinsed with clean water, and the next step can be carried out after it is fully dried. This can strengthen the effective bond between late concrete and early concrete. Slotting method is widely used in repairing, basically suitable for stress-free cracks, and the treatment effect is better.
Surface repair is the most common and convenient method. The Guankang Road Bridge is mainly suitable for the treatment of shallow cracks on the surface. The cracks are stable and have no effect on the structural bearing capacity. The usual treatment measures are to apply grout or epoxy cement on the surface of the crack, or paint, asphalt and other anticorrosive materials on the surface of the concrete. Sometimes in order to prevent the concrete from being affected by various effects, while protecting the cracks, it is possible to further develop the cracks, and then stick glass fiber cloth on the surface of the cracks and other measures. Surface repair is widely used in practice, but there are also many defects. First, this method may conceal the growth of some unknown cracks and cannot track their changes; second, this treatment method cannot penetrate into the cracks and may leave hidden dangers. So when using this seemingly simple method, it must be scientifically proven.
Structural reinforcement method
When cracks affect the mechanical properties of concrete structures, it is necessary to consider reinforcement methods to deal with concrete structures from a mechanical point of view. The main methods of structural reinforcement are: increasing the cross-sectional area of the concrete structure, wrapping section steel at the corners of the component, prestressing reinforcement, pasting steel plates, adding support points and spraying concrete reinforcement. Structural reinforcement methods involve changes in the shape of the structure and the force mode. Therefore, in the application, you should first communicate with the design and supervision to find out the reason, put forward a solution after stress calculation, and implement it after comprehensive demonstration.