04 roof crack seepage form: there are regular well shaped block cracks and water leakage in the basement roof
. 
03 floor corner inclined cracks: cast in place floor corner inclined cracks
. 
The basement crack prevention measures 01 waterproof concrete adopts low hydration heat cement, mixed with anti crack fiber and expansion agent, and the coarse aggregate gradation needs to be continuous
. 
It is recommended that engineering friends learn from them! There are seven types of basement cracks and their causes
. 
17
. 
The causes are as follows: the basement warehouse is too large or the setting of deformation joint and construction joint is unreasonable, the treatment of construction joint interface is sloppy or pouring with pressure water
. 
When the basement roof is used as temporary storage yard, equipment base and heavy-duty transportation road, the structure checking calculation shall be carried out, and the basement shall be reinforced by adding support
. 
The horizontal construction joint of the wall shall be pre poured with 20-40mm cement mortar with the same concrete mix proportion (the slurry shall be sent to the place by special chute), and then poured in layers (no more than 500mm)
. 
When there are large holes in the roof, it should be strengthened locally
. 
14 the basement roof line box uses a small round box, and the back is fixed with iron or shape steel
. 
It is strictly forbidden to pour in the foundation pit and foundation trench with accumulated water
. 
06 along the embedded pipe cracking form: cast-in-place floor along the embedded line pipe is easy to produce cracks
. 
02 beam side regular cracks: regular cracks appear on both sides of the beam on the upper surface of cast-in-place floor
. 
Causes: the concrete vibration is not dense, the floor thickness is not enough or the span is too large, or the building settlement is too large, resulting in the floor reaction force is too large, and the design of anti floating pile and anchor is unreasonable
. 
Form of water seepage around the pipe: there is water leakage at the place where the embedded sleeve and directly buried pipe pass through the waterproof concrete wall
. 
07 form of irregular cracks: irregular cracks appear on the surface of cast-in-place floor.
. 
The line pipe is located on the double bottom reinforcement of the roof, and should not be close to the upper part of the roof
. 
Each layer of waterproof coiled material shall be paved firmly, and an additional layer of coiled material shall be added
. 
Causes: the diameter of the embedded pipe is too large or the thickness of the floor is too thin, or the position is unreasonable, not placed in the middle of the floor
. 
05 roof box seepage form: basement roof box or pipe seepage
. 
Causes: the thickness of the basement roof is not enough or too thick, the concrete mix proportion and materials are improper, the vibration is not dense and the maintenance is poor, and the roof with soil is hollow floor
. 
Causes: the wall bushing is not welded with water stop ring, or the specification and size of water stop ring do not meet the requirements, and the welding quality of water stop ring is poor
. 
05 along the main reinforcement cracking form: cast-in-place floor along the reinforcement appear micro cracks
. 
Causes: the size of through wall screw water stop ring is too small or the welding is not full or the welding is not full, and the formwork is removed too early, which causes the concrete around the screw to be disturbed
. 
There are heaped loads on the roof of the basement or the heavy transport passage is not reinforced
. 
☀ Every day push the construction industry atlas specification, examination information, program details, construction skills and many other high-quality content, to build their own wechat platform! It’s right to pay attention to us! According to 21 common cracks in construction engineering, this paper summarizes the forms and causes of various cracks from three aspects: ① basement cracks, ② floor cracks, and ③ infilled wall cracks, and puts forward prevention measures
. 
13 the corner of base course of cushion waterproof layer shall be made into arc or obtuse angle
. 
During the joint review of construction drawings, the design and layout of anti floating piles and anti floating anchors should be focused on and checked to see whether they are reasonable, whether the thickness of the top plate meets the requirements, and whether the basement is covered with soil, and the hollow floor should not be used as far as possible
. 
06 waterproof concrete is poured continuously in layers, and the thickness of concrete layers is not more than 500mm
. 
04 form of cracks around the hole of embedded box: the construction reserved hole and water and electricity embedded box have extended cracks along the four corners of the hole
. 
There are seven types of floor cracks and their causes in the second section of floor cracks
. 
Click on architecture, pay attention to me all your life ☀ Architecture: solidified history ☀ Through architecture, we see the heritage and rise and fall of civilization; through architecture, we create the present and future of civilization
. 
Causes: the protective layer of floor bottom reinforcement and surface reinforcement is too small, the protective layer of vertical distribution reinforcement is too large or there is no distribution reinforcement, resulting in micro cracks in the reinforcement
. 
07 water seepage around through wall bolt: there is water seepage at the screw of external wall and pool wall
. 
The early strength of concrete is low, which is caused by hydration and shrinkage during curing
. 
02 construction joint water seepage form: basement deformation joint and construction joint new and old concrete joint along the joint leakage phenomenon
. 
It shall be tightly bonded according to the shape of the corner
. 
The clear width of the ring piece shall not be less than 40mm, and the sleeve with large diameter shall not be less than 80mm
. 
The last concrete pouring of each layer shall be completed before the initial setting, so as to avoid the construction cold joint
. 
07 before pouring concrete for construction joint of post pouring belt, the floating slurry and sundries on its surface shall be removed, and the dense concrete shall be chiseled, and then the coarse aggregate cement mortar shall be laid
.
Causes: there is no radioactive reinforcement in the outer corner of the end room, and the floor is loaded too early or too heavy or too concentrated
.
When the difference between inside and outside of concrete is greater than 25 ℃, surface insulation and internal cooling measures should be taken
.
11
.
The molding temperature of mass waterproof concrete should not be higher than 30 ℃
.
Causes: the construction holes of floor slab are not embedded with round holes or the holes are too large, and the reinforcement bars are not set around the holes
.
15
.
03 floor cracks seepage form: basement floor cracks and leakage phenomenon
.
The total effective curing time shall not be less than 14 days
.
The heat preservation and moisture conservation time shall not be less than 2 days, and the moisture conservation time shall not be less than 14 days
.
Causes: the reinforcement of negative moment reinforcement on beam surface is insufficient or the reinforcement is trampled, resulting in too large protective layer of negative reinforcement
.
Causes: the mix proportion and materials do not meet the requirements, or water is added to the site, resulting in excessive slump, excessive stacking load, premature formwork removal and poor maintenance
.
03 after the concrete pouring of basement exterior wall, the curing with formwork shall not be less than 2 days
.
After the final setting, the concrete shall be covered with plastic cloth and multi-layer materials with strong water holding capacity for heat preservation and moisture conservation immediately
.
When pouring concrete, first water wet, and then timely pouring concrete, and vibration dense
.
Causes: the waterproof concrete did not use low hydration heat cement or mixed with anti crack fiber and expansion agent, the formwork was removed too early and the maintenance was poor
.
01 through cracks: through cracks appear in the middle of cast-in-place floor
.
01 the water seepage forms of vertical cracks are as follows: after the construction of the main structure of the basement, vertical cracks appear in the middle area of the reinforced concrete wall and the side of the parapet, and there is water leakage
.
08 during the construction of underground works, the underground water level should be kept more than 500mm below the waterproof concrete, and the underground water should be drained
.
16
.
12
.
The crack resistant steel mesh should be added outside the main reinforcement on the upstream surface of basement exterior wall, and the spacing of steel mesh should be 100-120mm
.
Causes: the layout of wire box and wire pipe on the basement roof is unreasonable, and the reinforcement at the position of wire box is not strengthened
.
Increase the early strength and increase the reinforcement appropriately
.
After the formwork is removed, multi-layer water retaining materials shall be used to cover the concrete for curing for 3-4 days, and then continue to spray water for curing
.
It is strictly prohibited to use foam board to fix, and the reinforcement is strengthened in this part
.
Reasonable spacing of post cast strip should be set
.
And arrange a special person to tap the formwork, track and check whether the pouring and vibration are in place
.
It must be fixed firmly during installation without looseness
.
After the formwork is removed, the groove left behind shall be sealed tightly with sealing material and smoothed with polymer waterproof mortar
.
09 all kinds of steel bars or binding wires set inside the waterproof concrete structure shall not touch the formwork
.
All embedded parts passing through waterproof concrete must be fully welded with water stop ring, and the welding seam shall be dense and seamless
.
02 the basement floor concrete shall be vibrated twice before the initial setting, and shall be mechanically ground and pressed before the final setting
.
The finished product shall be protected after the completion of the waterproof layer
.
05 the water stop ring of through wall water stop screw shall be fully welded and full
.
04 mechanical vibration shall be used for waterproof concrete pouring to avoid missing vibration, under vibration and over vibration and ensure the uniformity and compactness of concrete
.
