The pre-sealing construction technology of the settlement post-pouring belt has improved the traditional post-pouring belt pre-sealing mode, which has the characteristics of fast construction speed, saving construction site, the waterproof layer can be directly constructed without treatment of the base layer, and the forming effect is good, and the construction progress of the pre-sealing of the post-pouring belt is greatly accelerated. It does not affect the settlement of the main structure, but also solves the normal insertion of basement leakage prevention and outdoor engineering, which can ensure that the basement decoration is synchronized with the main body, the outdoor project is synchronized with the exterior wall and decoration, and the quality of the project is ensured while ensuring the progress of the project. Realize the supporting first, the basement is backfilled in advance, and at the same time ensure that the post-pouring belt is poured 14 days after the main structure is capped.
Process
Schematic diagram of pre-sealing technology of post-pouring belt of basement roof
Operational points
1. Prefabricated cover mold making
The mold is made of wood, the prefabricated cover plate specification is 1.2m*1.2m*0.15m (length * width * height), the total width of the mold is 40cm wider than the width of the post-pouring belt, and the length is 1.2m. Mould height 15cm. After the mold is made, it can be used in turnover, and attention should be paid to the protection of the finished product of the mold during use.
Prefabricated cover moulds
2. Prefabricated cover plate steel bar binding
The reinforcing bar worker carries out steel bar cutting according to the size of the mold, adopts the three-level steel diameter 16@200 double-layer bidirectional, and carries out the binding of the reinforcing bar. After the reinforcement is tied, the hook needs to be embedded to facilitate subsequent lifting. The prefabricated cover plate needs to leave a hole of ф300 at an interval of 3 meters (the plate reinforcement is not opened).
Prefabricated cover plate reinforcement binding
3. Cover plate concrete pouring
After the cover plate reinforcement is tied, the concrete is poured, and the concrete is poured with the remaining materials when the main structure is poured, so as to save materials, and the film is covered and cured in time after the pouring is completed, and the curing time shall not be less than 7 days.
Post-molding effect
4. On-site installation of precast concrete cover plates
1. Preparation before installation
The surface of the hardened concrete construction joints in the post-pouring belt is chiseled, the loose stones are removed, and the hard cement and stones are exposed with a high-pressure water gun. The steel bars in the post-pouring belt should be adjusted according to the spacing of the steel bars in the construction drawings, and a special person should be arranged to restore the steel bars and fully tie the untied steel bars. The steel bars in the post-pouring belt have oil stains, floating rust and other phenomena, and special personnel are arranged to clean them. The formwork of the post-pouring belt and its formwork support system are inspected, and the support system adopts an independent support system, and the spacing of the large crossbars is 1.2-1.8m and the spacing of the vertical rods is 0.9m, which must be erected firmly and have sufficient rigidity and strength. The overlap between the formwork and the poured concrete surface is not less than 100mm, the joints are tight, the flatness of the bottom of the slab is ≤2mm, and the height difference with the poured concrete is ≤2mm. The formwork and formwork should have sufficient strength, stiffness and stability. The formwork should be tight and not leakage, and it should be ensured that there is no obvious friction between the old and new concrete after concrete construction. Clean up the debris in the post-pouring belt. Before placing the prefabricated cover plate, the steel bar and the formwork should be accepted by the supervision unit.
Post-pouring with high-pressure water gun cleaning effect
2. Prefabricated cover plate installation
The prefabricated cover plate is hoisted to the designated position of the post-pouring belt by the tower crane, and the prefabricated cover plate is placed manually according to the order that is placed sequentially from one side of the post-pouring belt to the other side, and the cover plate with the round hole of ф300 is placed every 3 meters, and a cover plate with a round hole is placed at the end of the post-pouring belt and the bend.
Place the DN300 cast iron pipe on the cover plate (the height is 200mm higher than the thickness of the backfill), the cast iron pipe is inserted into the cover plate 100mm deep, and the surrounding area is densely packed with cement mortar to ensure that the cast iron riser is installed firmly, as the pouring hole of the concrete in the future, and facilitate the pouring of the concrete in the post-pouring belt in the future, so as to prevent the self-compacting concrete from increasing the resistance at the bend, and the self-compacting concrete is difficult to continue to flow forward.
After the installation of the cast iron riser, the tape is used for temporary sealing treatment to avoid debris falling into the post-pouring belt and cannot be cleaned before the concrete pouring of the post-pouring belt.
Prefabricated cover plate mounting
3. Waterproof and protective layer construction
Carry out leveling layer construction before waterproof construction, waterproof can be one-time construction in place, in case of cast iron pipe according to the waterproof practice of pipe root node, cast iron pipe waterproof height of 2m (higher than 200mm backfill), waterproof protective layer construction after the completion of waterproof construction, pay attention to the finished product protection of cast iron pipe during construction, and make a waterproof additional layer of prefabricated cover plate at the post-pouring belt, each layer is 300mm wider than the cover plate.
Waterproofing of garage roof
Construction of waterproof protective layer on the roof of the garage
4. Earthwork backfill construction
Within 1m of the concrete pipe around the pouring hole, it is not allowed to fill the soil with a bulldozer or scraper, and it is not allowed to be compacted with a road roller; It can only be backfilled with manual shoveling and tamping with manual layering. In order to avoid squeezing the prefabricated reinforced concrete and causing the destruction of the waterproof layer.
5. Post-pouring with concrete pouring
14 days after the post-pouring belt reaches the capping of the main body, the post-pouring belt is poured, and the self-compacting micro-expansion concrete is used to pour the post-pouring belt through the cast iron pipe. After the concrete of each riser is poured to be consistent with the elevation of the backfill, and the concrete reaches its strength, the upper part of the riser is cut off, and the upper part of the riser is blocked and waterproofed by SBS membrane.
Post-pouring tape molding effect
6. Landscaping construction
In the process of landscaping construction, avoid the vehicle directly running over the riser. The riser should be marked accordingly.
7. Precautions
1) After the materials and semi-finished products and finished products enter the site, they should be inspected and accepted, and their varieties, proportions, specifications and performance must meet the requirements of design and relevant standards.
2) When installing the cast iron riser, it should be noted that the bottom of the riser is not allowed to extend into the post-pouring belt.
3) The concrete needs to be self-compacting, micro-expansion, impermeable concrete.
4) The post-pouring belt adopts an independent support system.
5) Before the closure of the prefabricated cover plate, it is necessary to inspect and treat the post-pouring belt to ensure that the operating conditions before the concrete pouring of the post-pouring belt are met, and the closure can only be carried out after passing the supervision and acceptance.
6) when carrying out earthwork backfill construction, need to be equipped with vehicle commanders, carry out earthwork transportation according to the designated route, avoid the destruction of the riser, and when backfilling the earthwork around the riser, it is forbidden to adopt mechanical tamping, and need to adopt manual layered tamping.
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