Concrete surface

Concrete surface repair

time:2018-12-06 source:维特编辑部browse:192

混凝土表面修补

Concrete surface repair

Concrete surface repair construction materials provisions
Concrete surface repair materials can adopt interface treatment materials and repair mortar, repair mortar compressive strength, tensile strength, flexural strength should not be lower than the base concrete.

Concrete surface protection materials should be selected according to the actual needs of the project, inorganic materials, organic polymer materials and composite materials can be used, and should meet the following requirements:
1. Under the action of environmental media erosion, the protective material shall not swell, dissolve, embrittlement or crack;
2. The protection materials should meet the requirements of durability protection of the structure. According to different environmental conditions and durability damage types, they should have the properties of carbonization resistance, permeability resistance, chloride ion resistance and sulfate corrosion resistance, and protection of steel bars.
3. The protective surface layer used for anti-wear shall not be worn away from the structure surface during its service life;
4. The protective surface layer shall be firmly bonded to the concrete surface and shall not crack, empty drum or flake during its service life.
The concrete surface repair construction shall conform to the following provisions:
1. Procedures for surface repair of concrete structures can be divided into base treatment, interface treatment, mortar repair construction and maintenance.
2. Base treatment: the area to be repaired shall be marked, and an incision with a depth of no less than 10mm shall be cut along the edge of the repaired area.
Remove the contaminated or damaged concrete in the surface area, the depth should not be less than 10mm;
The concrete at the edge of the restoration area shall be gouged, the concrete and exposed steel surface shall be thoroughly cleaned, the parts subject to chemical corrosion shall be washed with high-pressure water, and the corrosion shall be thoroughly removed.
3. Interface treatment: before repairing mortar construction, the exposed steel bars should be fixed and rust resistance treatment should be carried out. After drying, clean water should be used to thoroughly moisten the concrete base surface, and then spray or brush the interface treatment materials.
4. Repair mortar construction: according to the stress state of components, construction parts and site conditions, the method of daub, mechanical spraying and mold casting can be used for construction.
5. Maintenance: maintenance should be carried out after repairing mortar construction.

Concrete surface protection construction shall conform to the following provisions:
1. Before surface protection, surface treatment should be carried out to remove floating dust, oil stains or other chemical pollutants. For the deteriorated concrete surface layer, it is advisable to polish and remove it before washing with water.
To the surface that should not be washed with water, can blow with high pressure air sweep.
2. Concrete surface protection materials shall be prepared or modulated according to their proportion requirements.
3. When water-repellent impregnation is carried out on the concrete surface with permeable protective coating, spraying or brush coating method should be adopted for construction, and the concrete surface and interior should be fully dried during construction.
When using other organic materials, the bottom layer should be dry.
4. When using inorganic or composite materials for concrete surface protection, it is advisable to apply the construction, and should comply with the following provisions:
· in the construction of inorganic mortar material surface layer, the concrete base shall be fully wetted and shall not be empty or fall off.
When constructing the surface layer of composite materials, the concrete surface and interior shall be fully dried, and shall not bulge or flake.
When the concrete surface construction as a whole, the separation joints should be staggered joints.
When the thickness of the protective surface layer of the concrete facade or the top surface is greater than 10mm, layered construction is recommended.
The thickness of each layer of plaster should be 5mm ~ 10mm, and the construction of the next layer can only be carried out after the first layer is dry.
· spray (water or curing agent) should be applied when the surface is dry upon completion of construction.
Curing or covering plastic film and sack.
Wet curing period in case of cold or rain, should be covered, curing temperature should not be lower than 5 ℃.

Methods of concrete surface repair construction:
1. Coating method: when a large number of surface cracks appear on the concrete surface, manual or mechanical spraying method is adopted to coat the repair material on the concrete surface to play a role of surface sealing.
The thickness of the film is between 0.3 mm and 2.5mm, and the thickness of the film is strong enough to adapt to the change of cracks.
Choose repair material should be considered when using conditions (indoor and outdoor, environmental temperature and humidity changes, medium corrosion situation) and fracture activity, etc., for example, requirements of wear-resisting floor can choose epoxy asphalt coating, polyurethane coating of cool, get together ammoniac cool asphalt coating such as rigid coating, unstable fracture repair can choose cool polyurethane elastomers, rubber type acrylic cool coatings such as elastic coatings.
2. Increase the overall surface layer: when the number of cracks on the concrete surface is large and the distribution surface is wide, the method of adding a layer of cement mortar or fine stone concrete to the overall surface layer is often adopted.
In most cases, the overall surface layer should be equipped with two-way wire mesh.
When conditions are available, it is advisable to use the jet construction of cement mortar or concrete overall surface layer.
3. Epoxy plaster: this method can be used to treat the cracks with small amount and no concentration and width of >0. LMM.
4. Epoxy paste glass mesh cloth: generally use epoxy resin glue or epoxy tar glue, paste 1-2 layers of glass mesh cloth.
5. Surface suture: drill holes or grooves on both sides of cracks, put u-shaped steel bars or metal plates into holes or grooves, and use epoxy resin mortar and other non-shrink mortar to inject holes or grooves for anchoring, so as to achieve the purpose of suturing cracks.


Key words: bridge support replacement concrete surface repair concrete surface repair
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