What regulations should be complied with when continuing to pour concrete at the construction joints

<> in the construction joints. When continuing to pour concrete, the regulations should be complied with as follows:

1. The joint surface should be rough; The joint surface should be cleared of slurry, loose stones, and weak concrete layers, and should be cleaned up;

2. The joint surface should be fully moistened by sprinkling method, and there should be no stagnant water;

3. The strength of the concrete poured at the construction joint should not be less than;

4. Cement mortar for horizontal construction joints of columns and walls.

The thickness of the grouting layer should not be greater than 30mm, and the cement mortar of the grouting layer should be of the same composition as the concrete slurry;

5. Concrete strength grade of post-pouring belt.

and performance should meet the design requirements; When the design is not required, the strength grade of the post-pouring belt should be increased by one level compared with the concrete on both sides, and the technical measures to reduce shrinkage should be used for pouring.

What are the general requirements for concrete pouring?

1. The concrete should be poured before the initial setting, if there is a preliminary setting phenomenon, it should be stirred once vigorously to restore its fluidity before it can be put into the mold; If there is segregation, it must also be remixed before pouring.

2. The free fall height of concrete. When pouring concrete, the free height of concrete falling from a height should not exceed 2m, and the free falling height should not exceed 3m in the vertical structure, otherwise it should be cut along the string drum, chute, slip pipe or vibrating chute to prevent segregation of concrete due to excessive free fall height.

3. Before pouring the vertical structural concrete, the bottom of the pouring place should be filled with cement slurry or cement mortar with a thickness of 50 loomm and the same composition as the mortar in the concrete.

4. Layered pouring of concrete. Concrete pouring should be carried out in layers so that the concrete can vibrate and compact, and the upper concrete should be poured and vibrated before the lower concrete sets. The thickness of the concrete pouring layer should comply with the regulations.

5. The concrete pouring work should be operated continuously as much as possible, such as the upper and lower concrete pouring must be intermittent, and the maximum duration of the intermittent (including the entire duration of transportation, pouring and intermittent) shall not exceed the provisions.

6. Retention and treatment of construction joints.

This is not too clear, Pu Yuan, fair-faced concrete hanging board.

Answer] Zen ruin: a

The knowledge points assessed in this question are the requirements for pouring concrete in construction joints.

Option A is false: The compressive strength of the poured concrete belt should not be less than mm2.

Answer]: B When continuing to pour concrete at the construction joint, the following provisions should be met:

1) The compressive strength of the poured concrete should not be less than;

2) On the hardened concrete surface, the sailor mud film, loose stones and weak concrete layers should be removed, and fully moistened and rinsed, and no water should accumulate;

3) Before pouring concrete, it is advisable to brush a layer of cement slurry (can be mixed with an appropriate amount of Li Yu interface agent) at the construction joint or lay a layer of cement mortar with the same composition as the concrete;

4) The concrete should be carefully tamped to make the old and new concrete closely combined.

Continue pouring concrete at the construction joint, and the strength of the poured mixed concrete should reach ( ).

What regulations should be complied with when continuing to pour concrete at the construction joints

1. Construction joints refer to the joints formed between the concrete poured first and later due to the design requirements or construction needs to be poured in sections during the concrete pouring process.

2. When continuing to pour concrete at the construction joint, the following provisions shall be met:

1) The compressive strength of the poured concrete should not be less than;

2) On the hardened concrete surface, the cement film and loose stones and the weak concrete layer should be removed, and fully moistened and rinsed, and no water should be accumulated;

3) Before pouring concrete, it is advisable to brush a layer of cement slurry (can be mixed with an appropriate amount of interface agent) at the construction joint or lay a layer of cement mortar with the same composition as the concrete;

4) The concrete should be carefully compacted so that the new and old concrete are closely combined.

Preparation: 1. The joint surface should be rough;

2. The joint surface should be cleared of slurry, loose stones, and weak concrete layers, and should be cleaned up;

3. The joint surface should be fully moistened by sprinkling method, and there should be no stagnant water;

4. The strength of the concrete that has been poured at the construction joint should not be less than;

Answer]: A According to the content of the first section of the fourth chapter of the "Civil Engineering Textbook", item A should be selected.

Analysis] The concrete pouring of the post-pouring belt should be determined by the design.

Answer]: A The correct answer is A. Here's the answer:

According to the content of the first section of the fourth chapter of the "Civil Engineering Textbook", item A should be selected.

Analysis] The concrete pouring of the post-pouring belt should be determined by the design.

What should be done when continuing to pour concrete at the construction joints of concrete structures, the requirements are as follows. 1) before continuing to pour concrete at the construction joint, the concrete on the surface of the construction joint should be chiseled, and the cement slurry film (about 1mm), loose stone and the weak concrete layer on the surface are removed, and then fully watered and moistened, and there shall not be water accumulation in the joint; Correct the steel bars at the construction joints, and remove the oil stains and floating slurry on the steel bars. 2) when continuing pouring at the construction joint, should first spread a layer of destoned cement mortar with the same concrete strength grade at the construction joint, thickness about 10mm, or first pave a layer of concrete of half stone (the concrete that the construction mix ratio halves the amount of stone), and then continue pouring concrete, and carefully tamped, in order to ensure the close combination of old and new concrete.

3) when the post-pouring belt continues to pour concrete, the residence time of the post-pouring belt should meet the design requirements, if there is no design requirement, generally both sides of the concrete should stop for more than six weeks after pouring. The post-pouring belt is generally made of concrete with a higher strength grade than the original structure. In order to ensure that the post-pouring belt is closely combined with the concrete on both sides without leakage, an appropriate amount of expansion agent should generally be mixed in the concrete.