First, the construction of self-waterproof concrete structure
1 The material of waterproof concrete and the proportion of cement should be selected according to design requirements, and its strength level should not be lower than 32.5. The natural aggregate of the coarse aggregate is suitable, the particle size should be 5 ~ 40mm, and the mud content should not be greater than 1%. Requirements for the proportion of waterproof concrete: the impermeability required for the trial mix is 0.2 MPa higher than the design value; the amount of cement is not less than 300kg / m3, and the active admixture is not less than 280kg / m3; ~ 45%, water-cement ratio is not greater than 0.55; slump should not be greater than 50mm.
2 construction points
的 The formwork of the waterproof concrete project should be smooth, and the joints must be tight and leak-proof. Generally, it is not suitable to use bolts or iron wires to penetrate the concrete wall to fix the formwork. When bolts are used to penetrate the concrete wall to fix the formwork, water stopping measures should be taken. Such as the use of tool-type bolts, welded in the middle of the bolt water-proof steel plate, bolts at both ends of the block and so on. ① Tool bolt method: Fix and tighten the waterproof bolt with the tool bolt. When removing the mold, remove the tool bolt, and then seal the bolt groove tightly with caulking material and polymer cement mortar. Tool bolt method:
② The method of adding bolts and plugs: make grooves around the bolts on both sides of the structure, cut off the bottom of the flat grooves of the bolts after removing the mold, and then block the grooves with expanded cement mortar. The basement wall uses tool bolts:
③ The method of adding a welded water stop ring to the pre-buried casing: add a casing to the pull bolt, and the casing can also serve as a head support. After removing the mold, the bolts are pulled out, and the casing is sealed and compacted with expanded cement mortar. The pits left by the cushion are sealed in the same way. Schematic diagram of embedded casing support:
⑵ In order to prevent the water introduction of steel bars, the steel bar protection layer on the water front must not be less than 50mm, the steel bar on the floor must not contact the concrete cushion, iron bars or lead wires cannot be used to fix the steel bars on the formwork, and it is strictly prohibited to use steel bars as protective layer pads to prevent Water infiltrated along the reinforcement.
⑶ There is no bleeding or segregation before the waterproof concrete is poured, and the free fall height is not more than 1.5m.
机械 Waterproof concrete should be mechanically vibrated and compacted.
1 One set (6) of impervious test pieces shall be left for every 500m3 of continuous pouring concrete, and not less than 2 sets for each project.
⑹ Waterproof concrete should be cured naturally, and the curing time should be no less than 14 days.
3 Waterproof structure treatment
缝 Construction joint
The construction joint is a weak part of waterproofing, so it should not be left or left in construction. The floor concrete shall be continuously poured, and vertical construction joints shall not be left on the wall. The horizontal construction joint of the wall should not be left at the shear force and bending moment or where the bottom plate and the wall meet. Joint form of construction joint:
处理 Through-wall pipe treatment
Water supply and drainage, heating, and cable ducts should pass through the underground outdoor wall, and they should be waterproofed. Otherwise, water seepage will easily occur along the root of the pipe. In order to ensure the waterproof construction and easy installation of the pipeline, the location of the pipeline should be 25cm away from the corner or protruding part of the inner wall, and the distance between the pipes should be greater than 30cm. Directly buried type is suitable for wall-through pipes with a pipe diameter of <5cm:
The sleeve type is suitable for wall penetration with a diameter of> 5cm:
Wall-through box type is suitable when multiple wall-thru pipes are concentrated:
When pouring concrete, do not bump or vibrate the buried wall pipe. When backfilling the soil outside the wall, do not punch or tamp the wall pipe that protrudes from the wall to avoid water leakage due to impact.
⑶ Embedded parts
The embedded iron parts on the wall or floor of the basement are fixed with hangers or special tools to prevent water from seeping into the room along the iron parts. The embedded iron parts are subject to large forces. In order to prevent disturbing the surrounding concrete and damage the waterproof layer, the thickness of the end of the embedded parts to the outer surface of the wall must not be less than 25cm, and it should be partially thickened if it is less than 25cm. Embedded bolts on the basement floor:
变形 Deformed seam waterstops are currently most commonly used with embedded rubber (plastic) waterstops. Embedded rubber (plastic) waterstop:
Deformable rubber water stop deformation seam:
Deformed seam of adhesive neoprene sheet water stop:
⑸ After pouring
The waterproof layer at the post-casting belt is not disconnected. An additional layer is added and the water-proofing belt is attached outside:
The post-cast belt 2 partially thickens the cushion and adds steel bars. The poor settlement can cause the cushion to slope without tearing the waterproof layer:
There are 3 places of post-casting belts, which can partially thicken the bottom plate, and set water stop belts. Because the thickening of the bottom plate generally does not exceed 25cm, it is not suitable to set a buried water stop, it is recommended to use an external type water stop:
Construction of rigid waterproof layer of waterproof mortar
Rigid waterproof layer is suitable for waterproof layer of underground masonry structure or reinforced layer of waterproof concrete structure. Its ability to resist deformation is poor, and it should not be used when the structure is subject to more severe vibration loads or is subject to corrosion, high temperature and repeated freezing and thawing.
1 Primary treatment
The treatment of the base layer of the rigid waterproof layer is very important. The treatment of the base layer includes cleaning, watering, brushing, and leveling to keep the surface of the base layer moist, clean, flat, solid, and rough. Edges and irregularities exceeding 1cm should be cut into slow slopes, washed with water, and leveled with plain ash and cement mortar. Treatment of unevenness of concrete base:
For the honeycomb holes on the concrete surface, loose loose stones should be removed first, washed with water, and cleaned with plain ash and cement mortar alternately with the base layer. Treatment of honeycomb holes in concrete base:
For masonry made of lime mortar or cement mixed mortar, the joint should be cut to a depth of 1 cm, and the joint should be at a right angle. Caulking of brickwork:
Concrete construction joints shall be cut into sigmoid grooves along the joints. After washing with water, the plain ash shall be used as a base and the cement mortar shall be compacted and leveled. Treatment of construction joints in concrete structures:
2 Construction of cement mortar waterproof layer
The cement mortar waterproof layer is made by cross-layering with pure cement mortar and cement mortar. The number of times the waterproof layer is applied is determined by the design. The more common method is 5 times. The first layer of plain gray layer, 2mm thick, first wipe a 1mm thick cement slurry, scrape back and forth with an iron trowel, the cement slurry fills the pores on the surface of the base layer, and then wipe a 1mm thick cement slurry to level the layer. Brush on the surface of the cement paste in order. The second cement mortar layer has a thickness of 6 to 8 mm. It is performed after the initial setting of the cement mortar layer, and it is desirable that the cement mortar is thinly embedded in 1/4 of the thickness of the cement mortar layer. The above layers alternate. The construction joints of the waterproof layer need sloped stepped stubble, and the overlap of the stubble is overlapped layer by layer according to the hierarchical operation sequence. The location of the stubble is generally left on the ground, and the stubble must be 20cm away from the yin and yang angle. Waterproof layer continuous treatment:
Cross-layered application of waterproof layer of cement mortar:
The waterproof layer of the yin and yang corners needs to be rounded. The diameter of the yin corner is 5 cm and the diameter of the yin corner is 1 cm.
Construction of flexible waterproof layer
The flexible waterproof layer uses a coil waterproof layer. Currently, high-polymer modified asphalt waterproof coils and synthetic high-molecular waterproof coils are used in waterproofing projects of underground projects. The disadvantage of the flexible waterproof layer is that it is more difficult to repair after leakage. The method of paving the waterproof layer of the coil is divided into two methods according to the sequence of its construction with the underground waterproof structure. Underground outdoor anti-sticking method construction:
1 The method of external protection and external sticking is to lay the waterproof membrane on the facade directly on the outer surface of the outer wall of the waterproof structure. Construction procedure: pouring cushion layer → laying permanent protective wall → laying temporary protection wall with 300mm height → painting cement mortar screeding layer on the wall → applying additional waterproof layer at the corner Structural mortar cement screed leveling layer → facade waterproof layer construction → acceptance and protection layer construction. Coil material waterproof layer stubble practice:
Coiled waterproof layer:
2 The method of external and internal protection is that after the concrete cushion is poured, the permanent protective wall is completely laid, and the coil is laid on the cushion and the permanent protective wall. Schematic diagram of external defense and internal sticking method:
Underground outdoor anti-sticking construction panorama:
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