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Encyclopedia of concrete pouring construction and vibrating stick use method

2021-01-18

1. General requirements for pouring
 
1. The formwork should be watered and moist before pouring, and the cleaning opening of the wall and column formwork should be closed after removing debris and stagnant water.
 
2. The free fall height of the concrete falling from the bucket mouth shall not exceed 2 meters. If it exceeds 2 meters, measures must be taken to add cylinders.
 
3. When pouring vertical structural concrete, if the pouring height exceeds 3m, string tubes, pipes, chutes or openings on the side of the formwork should be used.
 
4. When pouring concrete, it should be done in sections, and the pouring height of each layer should be determined according to the structural characteristics and the density of steel bars. Generally, the layered height is 1.25 times the length of the active part of the plug-in vibrator, and the maximum is not more than 500mm. The layered thickness of the flat plate vibrator is 200mm.
 
5. The plug-in vibrator should be inserted quickly and unplugged slowly, and the insertion points should be evenly arranged, moved point by point, and carried out in order, without omission, to achieve uniform vibrating. The moving distance is not more than 1.5 times the radius of action of the vibrating rod (generally 300~400mm). When vibrating the upper layer, 50mm of the lower concrete surface should be inserted to eliminate the joint between the two layers. The moving distance of the plate vibrator should be able to ensure that the plate of the vibrator covers the edge of the tapped part.
 
6. Pouring concrete should be carried out continuously. If intermittent is necessary, the intermittent time should be as short as possible. The second layer of concrete should be poured before the initial setting of the front layer of concrete. The longest time for interrogation should be determined according to all types of cement and the initial setting conditions of concrete. Generally, more than 2 hours should be treated as construction joints.
 
7. When pouring concrete, special personnel should be sent to observe whether there is any displacement, deformation or blockage of the formwork steel bars, reserved holes, embedded parts, inserts, etc., and if any problems are found, the pouring should be stopped immediately, and should be before the initial setting of the poured concrete Finished.
 
Second, the concrete pouring method of the bottom plate
 
1. The concrete pouring is mainly carried out by two concrete pumps to the basement, and the tower crane cooperates with the hoisting, and the commercial concrete is used as the material.
 
2. Adopt the method of stepwise layered continuous pouring. The pouring direction of the first, second and third sections of the second floor of the basement is advanced from 7/oA to 1/oA axis; the pouring direction of the fourth, Ⅴ, and VI sections is from 1/oA axis. The D axis advances.
 
The pouring direction of sections I, II, and III of the basement floor advances from 7/oA to 1/oA axis; the pouring direction of sections IV, V, and VI advances from 1/oA axis to U axis. The pouring direction of each of the three pumps.
 
3. Accurately grasp the weather conditions before concrete pouring, avoid rainy weather, and try to arrange the concrete of the bottom tube body to be poured at night to reduce the heat of hydration inside the concrete in thicker areas. Before pouring concrete, it is necessary to set up horse benches, pedestrian passages and operating platforms. It is strictly forbidden to step on the steel bars directly. Whoever beats the passages will remove them. When pouring concrete, formwork, supports, steel bars, pre-embedded and reserved should be set up on duty, if there is displacement or deformation It should be handled in time to ensure the quality of concrete.
 
4. When pouring a concrete slab with a thickness greater than 500, the method of "segmented layering, inclined surface pouring, one slope, thin layer pouring, sequential advancement, and topping at one time" should be adopted, as shown in the attached picture. This kind of pouring method in which the concrete flows naturally to form a slope avoids the frequent disassembly, washing and extension of the conveying pipe, thereby improving the efficiency of pumping concrete and ensuring that the gap between the upper and lower concrete layers does not exceed 1.5 hours.
 
According to the actual situation that the concrete naturally forms a slope, two vibrators are arranged before and after each pouring zone. The first one is arranged at the unloading point to mainly solve the tamping of the upper concrete; the latter one is arranged at the foot of the concrete slope to ensure The compactness of the lower concrete. As the concrete pouring progresses, the vibrator will follow up accordingly to ensure the quality of the concrete at the entire height. As shown in the attached picture.
 
5. When pouring concrete at the post-pouring zone, a layer of cement mortar should be applied to the surface of the construction joint first. The concrete should not be cut directly close to the construction joint. When the machine is vibrated, it should be gradually advanced to the construction joint to strengthen the tamping of the construction joint and make it tightly integrated.
 
6. Vacuum water absorption is used for the surface bleeding of mass concrete. If excessive bleeding is found on the surface, the water-cement ratio should be adjusted in time. The bleeding removal when the concrete is poured to the top is shown in the figure.
 
7. Mass concrete is poured with thick cement paste on the surface. After the concrete is poured, it must be treated carefully. After about 2 to 4 hours, it is initially leveled with a long scraper according to the elevation, and it is rolled several times with an iron roller before the initial setting. , Then use a wooden trowel to flatten and compact to close the water-receiving cracks. After about 12 hours, cover the plastic cloth and sack again, and fully water and moisten it.
 
3. Concrete pouring of columns and walls
 
1. Before pouring columns and walls, or at the junction of newly poured concrete and lower concrete, cement mortar with a thickness of 50mm and the same proportion of concrete should be evenly poured on the bottom surface. The mortar should be poured into the mold with a shovel, and poured directly into the mold without a hopper.
 
2. The column wall concrete should be poured and vibrated in layers, and the thickness of each layer should be controlled at about 500mm. The concrete blanking points should be distributed and cyclically advanced and carried out continuously.
 
3. When pouring the wall opening, the height of the concrete on both sides of the opening should be roughly the same. The concrete should be vibrated evenly and densely, especially where the wall thickness is small, the structural reinforcement of the door and window openings and the densely connected staggered steel bars,
 
Φ25 vibrating rod should be used, and Φ50 vibrating rods should be used for other wall beams. Taking into account that the wall under the wall window hole cannot be directly vibrated after the concrete is sealed, the lower opening of the window hole can be reserved in advance, and the concrete can be poured to this position and vibrated After compaction, mold sealing and reinforcement. When vibrating, the vibrating rod should be more than 300mm away from the edge of the hole, and vibrate from both sides at the same time to prevent deformation of the hole. The lower part of the large hole should be opened and vibrated.
 
4. The concrete of the structural column shall be poured in layers, and the thickness of each layer shall not exceed 300mm.
 
5. When pouring beam slab concrete, the wall and column node areas are constructed according to high-strength grade concrete, and the interface is 500 at the side of the wall column as shown in the figure. At different nodes of wall column and beam slab
 
4. Concrete pouring of beams and slabs
 
1. The beams and slabs of the ribbed floor slab should be poured at the same time. The pouring method should start from one end and use the "push grout method" to advance. First, the beams are poured into a ladder layer by layer, and then they are poured together with the slab concrete when they reach the floor.
 
2. The virtual paving thickness of the floor slab pouring should be slightly larger than that of the slab. Use a flat vibrator to vibrate back and forth in the vertical pouring direction. Pay attention to constantly check with moving signs or plungers to control the thickness of the concrete slab. After vibrating, use a scraper or carriage to smooth the surface.
 
3. When pouring beams and slabs that are integrated with columns and walls, stop for 1 to 1.5 hours after pouring the columns and walls to make it initially solid, and then continue pouring.
 
4. Installation of construction joints: The floor slab should be poured along the direction of the secondary beam. The construction joints should be left within 1/3 of the span of the secondary beam. The surface of the construction joint should be perpendicular to the axis of the secondary beam or the slab surface. The construction joint of the one-way board is left at any position parallel to the short side of the board.
 
5. Block the construction joints with wooden boards and steel wire meshes.
 
6. The construction joints shall not be allowed to continue pouring until the compressive strength of the poured concrete is not less than 1.2MPa.
 
7. Before pouring concrete at the construction joints, the surface of the concrete construction joints should be chiseled, the cement film and loose stones should be removed, and washed with water. After removing the accumulated water, pour a layer of cement mortar or cement mortar with the same composition as the concrete and then continue to pour the concrete.
 
5. Stair concrete pouring
 
(1) The concrete of the staircase section is poured from bottom to top. Since the stair step adopts a closed template, a hole is opened on the step surface. The floor concrete is poured together with the stepping concrete, continuously advancing upward.
 
(2) The concrete of the stairs should be poured continuously.
 
(3) Position of construction joint: According to the structure, it can be set in the middle span of the stair platform or within 1/3 of the stair section.
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