A, quality common fault prevention and control institutions
Established by the project technical director as the team leader, the builder, inspector as the team leader, material engineer and team leader as members of the quality common fault prevention and control team. Before the construction of each subdivisional work, corresponding preventive measures should be formulated for the common quality defects that are easy to occur in the construction of this subdivisional work, and implemented in the construction.
Second, the common quality common fault and prevention
(A) Common quality problems
1, concrete honeycomb, pits, holes, etc.
(1) Honeycomb: The reason is that the concrete is too thick at one time, and the vibration is not solid or leaked; There is a gap in the template and the cement slurry is lost; Dense reinforcement, too small or too large slump of concrete.
(2) Exposed rebar: The reason is that the rebar cushion blocks are displaced, the spacing is too large, and the rebar is leaking, so that the rebar is close to the formwork, resulting in virtual vibration of rebar or Liang Lu rebar and slab bottom, resulting in rebar exposure.
(3) Pockmarked surface: The surface of the formwork is uneven, or the formwork is not wet enough or the formwork is dismantled too early, so the concrete on the surface of the component is easy to stick to the formwork, causing the pockmarked surface to peel off.
(4) Hole: The reason is that the concrete is stuck in the dense part of the steel bar, and the upper concrete continues to be poured without vibrating.
(5) Cracks and interlayers: Cracks and interlayers are caused by unclean construction joints or inadequate grouting.
(6) The section size deviation at the beam-column joint is too large: the main reason is that the rigidity of the column joint template is too poor.
(7) The surface flatness deviation of cast-in-place floor slab and stairs is too large: the main reason is that after concrete pouring, the surface is not carefully leveled with trowel.
2. Exterior wall tiles are prone to empty drum, falling off, uneven frame joints and wall pollution.
(2) Construction technical measures
1, main structure
(1) The measured values of any one of the three sub-items of structural engineering, such as section size, verticality and axial displacement, must meet the inspection and evaluation standards.
(2) Before concrete is cast, the cement mortar pad 1: 2 shall be bound under the joint of steel bar according to the regulations to ensure that the steel bar has enough protective layer, and the upper and lower rows of stressed steel bars and members with negative bending moment shall be provided with enough support to ensure the correct position of steel bar. Except for the one-way stress plate, all steel bar intersections of any component are bound.
(3) Steel bars and cement shall have quality certificates. After entering the site, according to the requirements of relevant specifications, samples shall be re-examined according to different batch numbers and specifications (and supervision representatives shall be invited to send samples for witness). Steel and cement without re-inspection or unqualified re-inspection are not allowed to be used.
(4) The template clearance of concrete engineering shall not adopt the method of square plate first.
(5) Concrete mixture ratio, the measurement of raw materials is the guarantee project of concrete subdivisional work, and the notice of concrete mixture ratio must be provided in the engineering technical data, and cement (bulk) sand, stone and water must be weighed when concrete is cast.
(6) Concrete and mortar test blocks must be numbered on the test block according to the unit project, and the production date of the test block should be indicated. The number and production date on the test block must be consistent with the concrete construction diary.
(7) Before the foundation backfill, after the completion of the main structure, the intermediate acceptance of the structure must be carried out by the departments of construction, construction, design, supervision and quality supervision. After the acceptance, the next working procedure can be constructed.
2. Exterior wall decoration
(1) When the structure is constructed, the external wall should be as flat and vertical as possible according to the standard of drywall, so as to create conditions for facing construction.
(2) After the stone comes into play, arrange special personnel for acceptance; Before use, it should be pre-laid, patterned and numbered, so that it can be taken according to the number when it is formally laid.
(3) Do a good job of jointing, and wipe the joints with cement slurry of the same color as the stone. When wiping seams, the slurry on the opposite brick must be removed in time.
3, floor engineering
(1) The building elevation of bathrooms, washrooms, balconies and other floors should be 20-30mm lower than that of the living room (except as required by the design), and the floor drain should be 5-8mm lower than the floor, and made into a disc shape. Cast-in-place concrete should be turned up along the ground of buildings prone to water accumulation 150mm, and the width should not be less than120 mm. ..
(2) At the junction, corner and middle of concrete aproll slope of external wall and wall, partition walls should be separated every 6 meters, and the gaps of partition walls should be filled with asphalt and leveled with aproll slope.
Third, technical measures to prevent leakage
external wall
1, transverse stare blankly hole of formwork supporting wall of external wall beam
(1) Remove the residual slurry and residue on the reserved hole wall, clean up the garbage and dust in the hole, fully spray water for wetting, and brush the reserved hole wall with 107 mucilage (107 glue dosage is 15% of cement dosage), with a thickness of 3-5mm1.
(2) Cut the brick that has been fully wetted overnight into two pieces from the length direction to the middle, scrape about 10mm thick cement mortar on the four sides of the brick, and embed it into the reserved hole from the inside and outside of the external wall to ensure that the mortar on the four walls of the brick is closely combined with the mortar on the wall of the cave. The outer half hole of the gable hole is not embedded with bricks, but embedded with C20 fine stone concrete (slump 6-8 cm) and compacted with fine stone concrete. Or all of them are packed with C20 fine stone concrete. The formwork is supported in a dustpan shape, and the concrete protruding from the wall surface is chiseled off after formwork removal.
(3) Cut a joint of about 10× 12mm around the brick or fine stone concrete embedded in the hole outside the external wall, embed 1: 2 cement mortar, and smooth the sealing surface.
2. Head joint of external wall
(1) Bricks or blocks shall be fully watered and wetted overnight to wash away the dust and garbage on the surface.
(2) False head joints are not allowed in brick masonry of external walls, and head joints must be scraped with mortar. The head joint on the outside of the block is caulked with 1: 2 cement mortar, with a thickness of about 5 mm ..
(3) There should be no blind seam. Where individual blind head joints are found, head joints with a width of more than 5mm and a depth of 50mm must be dug, and after the garbage and dust in the joints are removed, asbestos cement shall be used for caulking.
Floor pipe
1, a special person is responsible for filling the hole.
2, chisel in addition to the reserved cave wall loose animals, remove garbage and dust, a good bottom die, full water wet. Brush 107 glue mud on the outer wall of the pipeline and the reserved hole wall, and fill the hole when it is wet.
3. First make 10-20 thick 1: 2 cement mortar, then embed fine stone concrete slightly higher than the original gradation, about 20mm lower than the hole, compact the surface, smooth it, chisel it, list it after opening the hole, and do not touch the pipe within 24 hours.
4. Brush thick 1- 1.5mm polyurethane waterproof coating or waterproof cement slurry every 1-2 days.
5. After waxing the waterproof coating, use 1: 2 cement mortar for caulking, and the surface is flush with the floor.
6. After the floor is completed, use 1: 2 cement slurry around the pipe hole; Small steamed bread; .
Water tray, floor drain, four walls outside the water head
1, water tray, floor drain, etc. The outer wall of the downspout shall be coated with 3-5mm thick hemp white paint, and then embedded with 1: 1 cement mortar.
2. After the listing of the Bird's Nest, it is clearly stipulated that it is forbidden to touch or hold water within 24 hours.
The floor between toilets is full of water.
1, in the bathroom, a ++200mm chalk line pops up on the wall (above the structural plane), and a transparent plastic pipe or a long level ruler and a wooden ruler are used. According to the horizontal chalk line on the wall, the bathroom should be inclined to the floor drain with a slope of 0.5% to make the cake collapse.
2. When pouring fine stone concrete on the toilet floor, flat cake screed should be done first, and then fine stone concrete should be spread from far away from the door to nearby according to screed.
3. Finally, the footprints at the door must be filled with fine stone concrete, so as to meet the requirements of water flooding at the outlet.
The internal corner at the junction of the bathroom floor and the wall is leaking.
Garbage and dust should be removed from the two short sides of the balcony floor and the internal corners of the four sides of the bathroom floor. Sprinkle water to moisten fully, and paint with 107 mucilage once (the dosage of 107 mucilage is 15% of the dosage of cement), and divide two skins into triangular belts with 1: 2 cement mortar, and the interval is more than 12 hours.
Water pipe joints and water equipment
1, manhole
(1) On the inner plane of manhole cover plate, fill asbestos cement with width× height of 15× 10mm along the hole wall, then align and cover the hole and tighten the screws.
2, pour pot floor drain and sink head
(1) The rubber band is placed outside the drop head.
(2) Rubber belt is closely embedded with asbestos cement.
(3) Tighten the non-rolling end.
Vertical pipes of waste water pipes, sewage pipes and rainwater pipes are blocked by downpipes.
1, the upper opening of the riser is blocked with iron plate, and the cover moves up continuously with the height of the riser to prevent sundries from entering during construction.
2. The water outlet can also be plugged with a cork.
Surface sewage and wastewater pipelines, rainwater pipelines and inspection wells are leaking, flooding and poor drainage.
1, use T-level or set elevation control on the side wall of pipe groove, use bamboo piles to control the elevation of pipe bottom and CMC bottom, ensure sufficient flooding, and pull hemp thread at the top of pipe to control the verticality of pipe.
2, at the bottom of the pipeline according to the relevant provisions of the concrete pipe bed.
3, build by laying bricks or stones manhole brick must be fully wet, full knife paving mortar, full horizontal seam mortar.
4. Pad the joint of the pipeline with 20 thick 1: 2 cement mortar first, then insert the pipeline, water around the joint first, and then use 1: 2 cement mortar to embed the skin. According to the regulations, concrete nests are used around the pipeline. Do not touch the pipeline within 24 hours after mortar caulking and pipeline tying.
5. The bottom of the sewage manhole must be ground into a semicircle with the diameter of the inserted nozzle, and the surface is flush with the nozzle joint.
Four, installation engineering common fault prevention measures
Leakage of PVC-U plastic pipe
(1) Cause analysis:
1, pipeline quality problems, such as insufficient pipe wall thickness, too much filler for product components, and too large size deviation between straight pipe and pipe fittings, resulting in pipeline rupture and water leakage.
2. The quality problem of adhesive, because the quality of adhesive is unstable and the adhesion is not firm, the pipeline leaks repeatedly.
3, construction quality problems, many straight pipes and fittings are not coated with adhesive or the adhesive is not evenly coated; The insertion depth of socket joint is not enough, and the expansion joint is not constructed according to the specification requirements; In the subsequent civil construction and decoration process, due to the lack of experience and understanding of water supply plastic pipes, some hidden water supply plastic pipes were smashed or broken by impact drills. Because plastic pipes, unlike steel pipes and cast iron pipes, will produce obvious metal echoes when they are punctured, they cannot be found in time, and water leakage will be found after use; Installation workers do not understand the construction specifications, which leads to some accessories (such as risers, horizontal pipes, traps on elbows, inspection covers, etc.) that should not be stuck, which brings new troubles and inconvenience to the future maintenance of Qingtong; There is no water stop ring around the pipeline when the pipeline crosses the floor, and there is no embedded casing. Some toilets are not waterproof enough, which causes the floor to leak.
(2) Measures and countermeasures
1, strengthen the management of materials entering the site, strictly control the quality of incoming goods, and prevent unqualified products from entering the site. The building materials entering the site must have the production and sales license and product certificate approved by the local construction department, and the pipes, fittings and adhesives should be supplied by the same regular manufacturer.
2. Strengthen the construction management, improve the workers' training system, and implement the system of workers holding certificates.
3. Strengthen the technical disclosure of employees and make detailed disclosure of relevant regulations to employees.
4, more contact with the design institute, as far as possible in the design drawings to take concrete measures to prevent water leakage. Improve the structural form of the bathroom. (1) Choose the sanitary ware in the back row, and the floor-to-ceiling windows have side wall floor drains. (2) Designing local sunken toilets and reducing the number of holes passing through the floor can effectively and fundamentally solve the water leakage problem of the pipeline floor. The solution is to sink the toilet floor by 300mm and fill the sinking part with cement cinder. The drainage branch pipe of this floor is laid in the toilet cushion of this floor, and the side wall floor drain should be installed at the ground attachment of the sinking building. Even if the pipeline leaks, it will be discharged from the side wall floor drain. The above measures not only increase the flexibility of sanitary ware layout during the secondary decoration, but also solve the problem of water leakage in the bathroom, and effectively reduce the noise of drainage plastic pipes.
5, water supply and drainage riser is located in the tube well, tube hole or in the outer wall, indoor tube well every two layers or each layer as a transverse partition. When the riser passes through the floor as a fixed support point, a water stop ring with a thickness of not less than 20mm and a width of not less than 30mm should be built around the pipeline; When the riser passes through the floor as a non-fixed support point, a casing shall be installed, and the casing shall be not less than 50mm higher than the floor. The horizontal drainage main pipe in the pipeline transfer layer adopts flexible flared water supply plastic pipe.
Verb (abbreviation for verb) Other preventive and control measures
1, outer window panels, door and window covers, etc. It should be consistent when entering and exiting, and form a straight line from left to right.
2, cantilever part of the steel bar should be set below the steel bracket, reinforced engineering before the concrete is poured one by one hidden acceptance, and fill in the acceptance certificate. There must be a strength report of the test block when the formwork is removed, and the design strength can be confirmed before it can be removed. If there is temporary load on it, temporary support must be added after demolition.
3, for the completed project, if there are some places that need to be repaired, do it according to the designated foreman, and make detailed disclosure, and pay attention to the surrounding color consistency and finished product protection.
4, outdoor or exterior wall flush glass installation is completed, should pass the flush test, confirm no leakage rear can be said to be complete.
5, buildings and scaffolding fittings, in the construction organization design should have clear design and regulations, and facilitate the smooth progress of exterior wall decoration engineering.
6. Before construction, all sample drawings shall be signed by the inspector. Without inspection, construction or batch processing is strictly prohibited.
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