Is the post pouring tape of the building a construction joint?

The post-pouring belt is a temporary construction joint.

In order to prevent the harmful cracks that may occur in the cast-in-place reinforced concrete structure due to temperature and uneven shrinkage in the building construction, in accordance with the requirements of the design or construction specifications, temporary construction joints are left at the corresponding positions of the foundation bottom plate, wall and beam, and the structure is temporarily divided 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. The pouring time of the post-pouring belt should be selected when the temperature is low, and the cement can be poured or the concrete mixed with a trace amount of aluminum powder in the cement, 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, resulting in weak parts. The location of the post-pouring belt should also consider the different consumption factors of the template and other measures.

The post-pouring zone is divided into post-pouring settlement zone, post-pouring shrinkage zone and post-pouring temperature zone, which are used to solve the problems of differential settlement between the high-rise main building and the low-rise podium room, and the reduction of temperature stress in the shrinkage and deformation phase of reinforced concrete. This kind of post-pouring belt generally has a variety of functions of deformation joints, and the design should be considered to be mainly based on one function, supplemented by other functions. The post-construction pouring belt is the entire building, including the foundation and l:

The reserved joint in the construction of the part structure (the "seam" is very wide, so it is called the "belt"), after the main structure is completed, the concrete of the post-poured belt is completed, this "seam" does not exist, which not only solves the difference settlement between the high-rise main building and the low-rise podium in the whole structure construction, but also achieves the purpose of not setting up permanent deformation joints.

The construction joint is not able to ensure continuous construction during construction, and the post-pouring belt must be retained according to the design requirements. In order to eliminate the stress of the overall structure of the concrete, it must be retained, and the construction joints should not be left as much as possible if possible.

The post-pouring tape is not a construction joint. The construction joints are caused by the fact that the overall structural concrete is poured in two times, but the time interval exceeds the time of initial setting. For example, in a common superstructure, there is a construction joint between the column and the floor.

The pouring time of the post-pouring belt is generally 1-2 months later than that of the slabs on both sides, so there are two construction joints between the post-pouring belt and the slabs on both sides.

The post-pouring tape is not a construction joint.

The post-pouring belt can be divided into three kinds according to its function, and the post-pouring construction belt set up to solve the settlement difference between the main building and the podium of the high-rise building is called the settlement post-pouring belt. The post-pouring construction belt that is set up to prevent concrete from condensing, shrinking and cracking is called the shrinkage 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.

What type of post-pouring belt must be specifically determined according to the type of project, the engineering part, the on-site construction situation and the structural stress.

The disconnection or penetration of the rebar of the post-poured belt lies in the type of post-pouring belt joint. For the pouring belt after settlement, it is better to penetrate the steel bar; For the post-shrinkage pouring belt, it is better to disconnect the reinforcing bar; If the reinforcement is not opened, the shrinkage of the concrete near the reinforcement will be constrained, resulting in tensile force leading to cracking, thereby reducing the ability of the structure to resist temperature changes.

As for the construction, there should be no big difference between the two, according to the specific conditions of the project, retain a certain period of time (the retention time is generally retained until the structure is capped, with no less than 40 days), during which the early temperature difference and more than 30% of the shrinkage has been completed, and then the concrete filling density that is improved by one level than the thick structure becomes a continuous, integral, and non-expansion joint structure.

Construction joints refer to the joints formed between the concrete poured first and later due to the design requirements or the need for sectional pouring due to the design requirements or construction needs in the concrete pouring process. The construction joint is not a real "joint", it is only because the post-poured concrete exceeds the initial setting time, and there is a joint surface between the first-poured concrete and the first-poured concrete.

In order to prevent the cast-in-place reinforced concrete structure from causing harmful cracks that may occur after the cast-in-place reinforced concrete structure due to temperature and uneven shrinkage, in accordance with the requirements of the design or construction specifications, temporary construction joints are left in the corresponding positions of the slab (including the foundation bottom plate), walls and beams, and the structure is temporarily divided 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.

The difference between construction joints and post-pouring belts:

1. The post-pouring belt is to prevent the harmful cracks that may occur in the cast-in-place reinforced concrete structure due to temperature and uneven shrinkage, and in accordance with the requirements of the design or construction specifications, temporary construction joints are left in the corresponding positions of the slab (including the foundation bottom plate), walls and beams, and the structure is temporarily divided into several parts. The post-pouring belt is an effective measure that can not only solve the settlement difference but also reduce the shrinkage stress, so it is more widely used in engineering.

2.The construction joint refers to the joint formed between the concrete poured first and later due to the design requirements or construction needs to be poured in sections in the process of concrete pouring. The construction joint is not a real "joint", it is only because the first pouring concrete exceeds the initial setting time, and there is a joint surface between the concrete and the later pouring concrete, which is called the construction joint.

What problems should be paid attention to in the construction of construction joints and post-pouring belts? 1.The plane position of the post-pouring belt should be comprehensively considered in combination with the layout of the foundation and its above structures, and should be set near the third division line of the column spacing, so as to avoid the maximum stress part of the excavation plate in the upper building.

2.The post-pouring belt should be arranged in the simplest part of the reinforcement, to avoid overlapping and scattering with the beam position, the post-pouring belt of the upper frame structure can be staggered with the plane position of the foundation post-pouring belt, but it must be in the same span, and the skin can be eliminated and zigzag, and attention should be paid to the consistency principle of the position of the basement and the superstructure joint. 3.

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

First, the reference is different.

1. Construction joint: It is a joint formed between the concrete poured first and later due to the design requirements or construction needs to be poured in sections in the process of concrete pouring.

2. Deformation joint: It is a general term for expansion joints, settlement joints and shockproof joints.

3. Post-pouring belt: In order to prevent harmful cracks that may occur in cast-in-place reinforced concrete structures due to uneven shrinkage or uneven settlement in building construction.

Second, the characteristics are different.

1. Construction joint: construction joint is not a real "joint", it is only because the concrete is poured first more than the initial setting time, and there is a joint surface between the concrete poured later, and the joint surface is called the construction joint.

2. Deformation joints: Buildings often deform under the action of external factors, resulting in cracking and even destruction. A deformation joint is a construction joint that is reserved for this situation.

3. Post-pouring belt: In order to adapt to the influence of factors such as environmental temperature changes, concrete shrinkage, and uneven settlement of structures, concrete belts with a certain width are reserved in beams, slabs (including foundation bottom plates), walls and other structures and poured after a certain period of time.

Third, the regulations are different.

1, construction joint: when concrete needs to be heated and cured, the temperature difference between newly poured concrete and adjacent hardened concrete or geotechnical medium shall not be greater than 15 °C; The temperature of the foundation surface in contact with the concrete must not be lower than 2°C.

2. Deformation joint: the building structure joint set up when the height of the same building is very different, the upper load is unevenly distributed, or when it is built on different foundation soils, in order to avoid uneven settlement and cracking of the wall or other structural parts of the hood.

3. Post-pouring belt: It should be decided according to the actual situation of the thickness of the wallboard, and the wallboard with a general thickness of < 300mm can be made into a straight seam; The wall panel with a thickness of 300mm can be made into a stepped joint or a symmetrical groove shape up and down; The wall panel with a thickness of 600mm can be made into a concave or polygonal concave section.

1) It should be decided according to the actual situation of the thickness of the wallboard, and the wallboard with a general thickness of 300mm can be made into a stepped joint or a symmetrical groove shape up and down; The wall panel with a thickness of 600mm can be made into a concave or polygonal concave section.

2) Whether the reinforcement is kept in its original state or cut off the beam is determined by the type of post-pouring belt. The reinforcement of the pouring belt should be penetrated after settlement, the reinforcement of the telescopic pouring belt should be disconnected, and the plate reinforcement of the beam and plate structure should be disconnected, but the beam reinforcement is penetrated, if the reinforcement is not opened, the concrete shrinkage near the reinforcement will be greatly restricted, and the tensile stress cracking will be generated, thereby reducing the ability of the structure to resist temperature stress. The post-pouring belts on different sections should be connected in zigzags.

3) After pouring with concrete, generally non-shrinkage concrete should be used for pouring, and expansion cement can also be mixed with expansion agent and ordinary cement. The strength of the concrete is at least the same as the original pouring concrete or increased by one level.

4) construction quality control, the connection form of the post-pouring belt must be carried out in accordance with the construction drawing design, the formwork must be plugged plate or steel mesh, and the joint interface form is installed on the board with a convex bar. Before pouring concrete, the joints should be carefully cleaned, chiseled, scoured, and the displaced steel bars and stools should be reset, and the concrete must be vibrated and compacted, especially the basement floor should be carefully dealt with to improve its own waterproof ability. After the first pouring of the post-pouring belt, protective measures should be taken, the top should be covered, and the fence should be protected to prevent garbage from entering the joint, steel bar pollution, trampling and deformation, which will bring difficulties to the cleanup.

5) the beam plate on both sides of the post-pouring belt is in a cantilever state for a long time before the unfilled concrete, so the formwork support on both sides before the non-pouring, the rougher combustion can not be removed, and the concrete strength reaches more than 85% after the pouring belt is poured together, and the concrete is protected after pouring, and the observation record is maintained in time.