What does post pouring strip mean on construction?

Post-pouring tape. It is a cast-in-place reinforced concrete structure in building construction to prevent it.

Harmful cracks that may be produced due to uneven shrinkage or uneven settlement, in accordance with the requirements of the design or construction specifications, the concrete belt left at the corresponding position of the foundation floor, wall and beam.

The post-pouring belt temporarily divides the structure into several parts, and after the internal shrinkage of the component, the construction joint is poured after a certain period of time.

Concrete, the strip that connects the structure into a whole. The pouring time of the post-pouring belt should be selected when the temperature is low, and the cement or cement can be mixed with a trace amount of aluminum powder concrete, and its strength grade should be one level higher than the strength of the component, so as to prevent cracks between the new and old concrete and the formation of weak parts. The location of the post-pouring belt should also consider the different consumption factors of the template and other measures.

Precautions for post-pouring belt construction:

1. The setting of the post-pouring belt should follow the design principle of "both anti-defense and prevention". Because of the cracking problem of ordinary concrete, the purpose of setting the post-pouring joint is to release most of the restraint stress, and then fill the joint with expanded concrete to resist the residual stress.

2. Structural design.

The post-pouring belt designed due to the consideration of settlement reasons should be set up in strict accordance with the design drawings in the construction; When it is necessary to set up the post-pouring belt due to construction reasons, it should be determined according to the specific situation of the project, and the position left should be approved by the design unit.

3. The spacing of the post-pouring belt should be reasonable, the spacing of the post-pouring belt of rectangular structures can generally be set to 30 40m, and the width of the post-pouring belt should be considered to facilitate construction operation, and according to the requirements of structural structure, the general width is 700 1000mm.

To put it bluntly, it is a belt left when pouring concrete in construction, and the role is to prevent the deformation caused by thermal expansion and contraction of concrete, the plane has a horizontal post-pouring belt, and the wall has a vertical post-pouring belt, which is generally poured two months after the concrete pouring is completed, and then this belt is poured concrete, so it is called a post-pouring belt. Generally, the concrete strength of the pouring belt after pouring is one grade higher than the original concrete strength there. You see that there is also a gap in the concrete pavement, which is the same reason.

According to the requirements of the design or construction specification, a temporary construction joint is left at the corresponding position of the foundation bottom plate, wall and beam, the structure is temporarily divided into several parts, and after the internal shrinkage of the component, the concrete of the construction joint is poured after a certain period of time, and the structure is connected into a whole. Function: 1 Solve the settlement difference.

2.Reduces the effect of temperature shrinkage.

The post-pouring belt is a harmful crack that may occur in the construction of the cast-in-place reinforced concrete structure due to its uneven shrinkage or uneven settlement.

In accordance with the requirements of the design or construction specifications, temporary construction joints are left at the corresponding positions of the foundation floor, wall and beam.

Function: Solve the settlement difference and reduce the temperature shrinkage.

Classification of post-pouring belts:

In order to solve the settlement difference between the main building and the podium of high-rise buildings, the post-pouring construction belt is called the settlement post-pouring belt.

The post-pouring construction zone set up to prevent the concrete from cracking due to temperature changes is called the temperature post-pouring zone.

In order to prevent the construction area from being too large, the structure is due to temperature changes, and the concrete shrinkage and cracking are set up as the expansion and post-pouring belt.

The post-pouring belt refers to the cast-in-situ integral reinforced concrete structure, only the temporary ribbon joint that remains during the construction period, plays the role of digesting the settlement shrinkage deformation, the width of the joint is 800-1000mm, according to the needs of the project, after retaining a certain period of time, and then pouring the concrete cushion to become a continuous whole structure.

Scope of application. This method is suitable for the construction of the post-pouring belt in the cast-in-place integral reinforced concrete structure of high-rise residential buildings, public buildings and super-long structures of high and low structures, and the construction of the post-pouring belt in other structures with special requirements can refer to this method.

Construction technology. a, due to construction reasons need to set up the post-pouring belt should depend on the specific structure shape of the project, the distance is generally 20-30m, the location should be approved by the design institute.

b. The retention time of the post-pouring belt. It should be determined according to the design requirements, and when the design is not required, it should not be less than 40 days: without affecting the construction progress, it should be retained for 60 days.

c. Protection of post-pouring belt. After the post-pouring belt of the foundation cushion cap is left, protective measures should be taken to prevent garbage and debris from falling in. The protective measures can be covered with a wooden cover on the epithelial steel bar of the cushion cap, and both sides of the cover plate should be wider than the post-pouring belt by more than 501 mm.

The vertical post-pouring strip of the basement exterior wall can be protected by brickwork. The bottom mold of the beam and the supporting frame of the sorghum plate on both sides of the floor panel post-pouring belt shall not be removed.

d. Closure of the post-pouring belt. When pouring structural concrete, a layer of steel wire mesh should be set on the template of the post-pouring belt, and the steel wire mesh does not have to be removed during the construction of the post-pouring belt. The post-pouring belt is set up with flat joint, tongue-and-groove type and stepped type, each form must carefully chisel the floating slurry of the entire concrete surface before closing, and chisel into a rough surface, completely remove the garbage and debris in the post-pouring belt, and water and moisten overnight, lay cement slurry, to ensure that the concrete of the post-pouring belt is well connected with the concrete of the first pouring and smashing.

The water-stopping treatment of the basement floor and the post-pouring belt of the exterior wall shall be carried out according to the design requirements and the corresponding construction acceptance specifications. The sealing material of the post-pouring belt should be made of micro-expansion concrete (micro-expansion agent UEA can be mixed into ordinary concrete, and the amount is 12-15) should be used to improve the design strength grade of the structural concrete that is poured first, and it should be kept warm and moisturizing for no less than 14 days.

The post-pouring belt is a harmful crack that may occur in the construction of the cast-in-place reinforced concrete structure due to its uneven shrinkage or uneven settlement.

In accordance with the requirements of the design or construction specifications, the concrete belt left at the corresponding position of the foundation slab, wall and beam. The post-pouring belt temporarily divides the structure into several parts, and after the internal shrinkage of the components, the concrete of the construction joint is poured after a certain period of time, and the structure is connected into a whole zone.

The pouring time of the post-pouring belt should be selected when the temperature is low, and the concrete mixed with trace aluminum powder in the cement or cement barrier can be used, and its strength grade should be one level higher than the strength of the component, so as to prevent cracks between the new and old concrete, forming weak parts, and setting up the position of the post-pouring belt should also consider different consumption factors such as formwork and other measures.

Precautions for post-pouring tape

1. The setting of the post-pouring belt should follow the design principle of "both resistance and prevention, and prevention-based", because there is a cracking problem in ordinary concrete, and the purpose of setting the post-pouring joint is to release most of the restraint stress, and then fill the joint with expanded concrete to resist the residual stress.

2. In the structural design, the post-pouring belt designed due to the consideration of settlement reasons should be set up in strict accordance with the design drawings during construction; When it is necessary to set up the post-pouring belt due to construction reasons, it should be determined according to the specific situation of the project, and the position left should be approved by the design unit.

3. The spacing of the post-pouring belt should be reasonable, the spacing of the post-pouring belt of rectangular structures can generally be set to 30 to 40m, and the width of the post-pouring belt should be considered to facilitate construction and operation, and according to the requirements of structural structure, the general width is 700 to 1000mm.

4. The slabs and wall reinforcements passing through the post-pouring belt should be disconnected and lapped, so that the concrete of the two parts can shrink freely; The beam reinforcement can be uninterrupted, and the raft foundation bottom plate and the foundation bottom plate beam stressed steel bar must be penetrated, and the stressed main reinforcement should be welded and connected.

5. The post-pouring belt cannot remove part of the formwork and pillars before pouring concrete, otherwise it will cause the beam plate to form a cantilever and cause deformation; After construction, the position of the pouring belt should be selected in the part of the structure with less stress, generally near the reverse bending point of the beam and slab, the bending moment at this position is not large, and the shear force is not large; It can also be selected in the middle of the beam and plate, although the bending moment is too large, but the shear force is very small.

The above content reference: Encyclopedia - post-pouring belt.