Abstract: the main structure to achieve self waterproof, must use self waterproof concrete. It can improve the compactness and impermeability of concrete by adjusting the mix proportion or adding admixtures.
1、 According to different leakage parts and types, the waterproof materials should be selected and used correctly and reasonably.
Different materials are used:
For example, quality assurance measures should be taken for anti cement concrete, thickness of sprayed coating, finished product protection, plastic waterproof board, embedded and attached waterstop and caulking materials for different joints.
2、 Selection of waterproof materials
High, medium and low grade materials of different grades must be selected according to the requirements of waterproof grade of design structure.
The selected waterproof material must have the following necessary technical properties.
① It has good impermeability, good water resistance and strong adaptability. It has good acid and alkali resistance in different environments.
② It can also bond with other materials, such as concrete.
③ It has a certain anti stripping strength.
3、 Waterproof materials for different parts
1) In order to achieve self waterproofing of main structure, self waterproof concrete must be used as the main body. It can improve the compactness and impermeability of concrete by adjusting the mix proportion or adding admixtures.
2) In order to improve the waterproof performance of the main structure, additional waterproof layer is adopted. The following additional waterproof layers are commonly used:
① Mortar waterproof layer:
Based on cement, the mortar is mixed with special additives, such as waterproof agent, expansion agent, polymer, etc. The purpose of impermeability is achieved by improving the compactness of cement mortar and reducing the shrinkage crack (improving the micro expansion crack resistance).
② Waterproof membrane:
The new method can also be used to improve the waterproof performance of the underground structure. It is required that the coil material and cementing agent should have good durability, water resistance, puncture resistance, corrosion resistance, bacteria resistance, etc. At the same time, it has the tensile property to adapt to the settlement deformation of the structure.
The commonly used coiled materials are: SBS modified asphalt waterproof membrane, self adhesive rubber asphalt waterproof membrane, EPDM rubber membrane, chlorinated polyethylene waterproof membrane, polyvinyl chloride waterproof membrane, etc.
③ Waterproof coating:
When the main structure is difficult to be pasted externally, the external coating and spraying waterproof coating can be used as the waterproof layer.
1. The coating used should have good adhesion with the concrete base surface, as well as good water resistance, corrosion resistance, non-toxic (low toxicity) and non flammable properties.
Inorganic coatings, in addition to durable adhesion, but also need to have wear resistance and puncture resistance.
Organic coatings should have good adhesion with the base surface, and can be extended to adapt to the deformation of the structural base.
Because it is difficult to ensure the durability of organic waterproof layer in the construction of underground wet foundation, composite waterproof layer is commonly used; inorganic waterproof layer and permeable crystalline waterproof material are used first, and then organic waterproof layer is used.
2. The commonly used waterproof coatings are: R type mechanical coating, polymer mortar and cement crystalline waterproof coating.
Organic waterproof coatings are: polyurethane waterproof coating (reactive type).
Water emulsion waterproof coatings are: silicone rubber emulsion, acrylic waterproof coating.
④ Application of waterproof grouting materials:
Grouting materials are divided into organic and inorganic.
1) The commonly used inorganic grouting materials include: single liquid cement slurry, mortar, cement plus bentonite, cement water glass, modified sodium silicate and clay solidified slurry, and special cement (ultra-fine cement, self leveling cement, double quick cement) grouting materials.
2) Organic grouting materials include polyurethane grouting material, acrylamide grouting material, water-soluble polyamide ester grouting material, epoxy resin grouting material and epoxy polyamide grouting material.
⑤ Waterproof sealing material:
The sealing material is applied in the structure crack, construction joint, deformation joint (settlement, expansion) and connection joint.
1. The sealing material shall be wear-resistant, corrosion-resistant, non combustible, colored, waterproof and insulating, and shall not be brittle or cracked at low temperature and soften and flow under high temperature; it shall be adaptable to the deformation of the structure; it shall have good operability, and its coating surface shall be smooth and smooth; it can be extruded in the packaging, and can be extruded from the outlet to the depth of the gap, and can be firmly bonded with the two walls without degumming; the interior is soft The surface is dry and hardened, and has good weather resistance and durability.
2. Common sealants are:
Oil based sealant is a low-grade sealing material;
Solvent sealant, reasonable price, convenient construction, brush removal;
Chemical reaction sealant, high price, wide application.
"Water swelling" rubber strip, putty paste, self-adhesive rubber strip.
At present, polysulfide rubber is better used, but the cost is higher and the operation is more troublesome.