What kind of concrete cracks need to be treated, and which specification is it?

See the national standard "Code for Acceptance of Construction Quality of Concrete Structure Engineering" GB50204-2002 for the treatment of appearance defects of concrete structures.

Appearance defect of concrete structure and its treatment;

Exposed reinforcement means that the main reinforcement, auxiliary reinforcement or stirrup in concrete are partially exposed on the surface of structural members. The reasons for the reinforcement exposure are: too few or missing reinforcement pads, or displacement during vibration, which makes the reinforcement close to the template; The cross section of the structural member is small, the steel bar is too dense, and there are stones stuck on the steel bar, so the cement slurry can't fill around the steel bar.

Improper concrete mix proportion leads to segregation, and slurry is lacking or leaking near the formwork; The concrete protective layer is too small or the concrete at the protective layer leaks or vibrates falsely; The wooden formwork is not watered and wet, and it absorbs water, bonds or removes the formwork prematurely, resulting in the lack of edges and corners and the exposure of tendons.

When facing, the exposed rebar on the surface shall be brushed with concrete residue and rust, and then the exposed rebar shall be leveled with 1:2 or 1:2.5 cement mortar; When the exposed reinforcement is deep, the weak concrete and protruding particles should be chiseled away, washed clean, and compacted with fine stone concrete with higher strength grade than the original concrete, and the maintenance should be strengthened.

Extended data:

If there are cracks in the concrete of the building, the cracks below 0.3mm are generally self-healing cracks, so don't worry. What if there is more than 0.3mm? Today, Bian Xiao will teach you the treatment measures of concrete cracks and the common scheme specifications. It is very suitable for the treatment of concrete cracks in some small buildings.

Common concrete crack schemes generally include a series of compilation, such as an overview of crack location, compilation basis, construction preparation (technical preparation, labor organization preparation, recording and treatment process preparation), construction method (construction technology, construction preparation, construction method-crack treatment, installation of grouting pipe, plugging V-shaped groove with cement, preparing epoxy resin glue, pressure grouting, matters needing attention and quality inspection) and so on. According to different projects, the scheme is also different. Treatment measures are different for concrete cracks.

Surface treatment method

The application scope of surface coating and surface repair method is thin and shallow cracks that are difficult to fill with cement slurry, capillary cracks whose depth is not up to the surface of steel bars, watertight cracks, non-telescopic cracks and cracks that are no longer active. The method of surface repair (geomembrane or other waterproof sheets) cannot be used for seepage control and plugging of large-area cracks.

Filling method

Filling cracks in concrete directly with repairing materials is generally used to repair paid cracks, with simple operation and low cost. It is suitable for cracks with crack width less than 0.3mm, or cracks with shallow depth, or concrete cracks with fillers that are difficult to achieve ideal grouting effect. And simple treatment of small-scale cracks.

injection process

This method is a widely used method, which can be used to treat small cracks to large cracks, and the treatment effect is very good. Using the accompanying equipment, the mortar for repairing cracks is injected into the cracks at a pressure of 0.2mpa-0.4mpa to achieve the purpose of plugging. This method belongs to the traditional method and has a good effect. You can also use the elastic joint filler to inject the joint filler into the crack without electricity, which is very convenient and the effect is ideal.

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