How to apply correctly in the process of concrete pouring?

Whether the axis position and cross-sectional size of the formwork before pouring are consistent with the construction drawing;

Whether the specifications, models, quantities, and lap lengths of steel bars meet the design requirements, and make acceptance records of concealed projects;

Before pouring, the debris that should fall into the formwork; All kinds of stains and oil stains on the steel bar are cleaned up, and the gap and cavity of the template are strictly blocked; The formwork should be watered with water;

The concrete of on-site mixing and on-site transportation should be connected to the transportation channel on the floor, erected with a steel pipe frame, 30 50cm of the layout, and the line erected should be determined according to the pouring procedure, if it is to pump commercial concrete, the conveying pipe frame should be poured to the pouring area in the order of the pouring procedure;

When pouring concrete, in order to avoid the phenomenon of segregation, the free height of concrete falling from a height, the free fall height should not eat more than 2m, when the free fall height is larger, a chute or a string drum should be used to prevent concrete segregation, the chute is generally made of wooden boards, the surface is covered with a thin steel plate, and its horizontal inclination angle can not exceed 30 ° when used, the string drum is made of thin steel plate, the medium barrel is about 700mm long, and the hook and loop are used, and a buffer plate is arranged in the cylinder;

Due to the performance factors of the vibrating tool, when the thickness of the concrete is too large, it needs to be poured in layers, and the thickness of the permissible paving concrete for each pouring is when it is incorporated and vibrating its vibration, and the thickness of the permissible paving is the multiple of the length of the acting part of the vibrator. Generally about 50cm, with a plate vibrator, the thickness of the paving is allowed to be 200mm, if there is no vibrator in some areas, and the manual vibrating is used, it is generally about 200mm, according to the density of the steel bar to determine;

When pouring the concrete of the vertical structure, the cement mortar with the same composition as the concrete mortar should be poured at the bottom of the newly poured concrete and the concrete concrete.

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 the 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 carried out continuously as much as possible, such as the upper and lower concrete pouring must be intermittent, and the maximum duration of the interval (including the entire duration of transportation, pouring and intermittent) shall not exceed the regulations.

6) Retention and treatment of construction joints.

If the concrete cannot be poured continuously due to technical reasons or the limitation of equipment and manpower, and the intermittent time in the middle exceeds the allowable time, the construction joint should be determined in the appropriate position in advance. Because the adhesion of the old and new concrete is poor, it is a weak link in the component, so the construction joint should be left in the part where the structural force (shear force) is small and convenient for construction. Horizontal seams should be left for columns, and vertical seams should be left for beams and plates.

It should be mixed evenly, the color should be consistent, and the water-cement ratio should be strictly controlled.

Before pouring, the watering of the formwork should be self-wetting, and the cleaning port of the wall and column formwork should be closed after removing debris and stagnant water. The free falling height of concrete shall not exceed 2m, and if it exceeds 2m, it must be poured in layers and strings. When pouring concrete, it should be carried out in sections and layers, and the pouring height of each layer should be determined according to the structural characteristics and the density of steel bars.

Generally, the layering height is times the length of the plug-in vibrator, and the maximum is not more than 50cm, and the layering thickness of the plate vibrator is 200mm. The use of plug-in vibrator should be quickly plugged and unplugged slowly, and the insertion points should be evenly arranged, moved point by point, and carried out in order, without omission, so as to achieve uniform vibrating. The moving distance is not more than the multiple of the radius of the vibrating rod (generally 300 400mm).

When vibrating the previous layer, 50mm should be inserted into the concrete surface of the lower layer to eliminate the joints between the two layers. The spacing of the plate vibrator should be able to ensure that the vibrator plate covers the edge of the compacted part. Concrete pouring should be carried out continuously, and if intermittent is necessary, the intermittent time should be kept as short as possible.

And the secondary layer of concrete should be poured before the initial setting of the previous layer of concrete. The maximum intermittent time should be determined according to all cement varieties and concrete initial setting conditions, and generally more than 2 hours should be treated according to the construction joint. When pouring concrete, special personnel should be sent to frequently observe whether there is displacement deformation or blockage of formwork, steel bars, reserved holes, embedded parts, reinforcements, etc., and the pouring should be stopped immediately if problems are found, and the rectification should be completed before the initial setting of the poured concrete.

First: Check.

Whether the copy template is accurate and firm. Second, at least one person must know how to use the vibrator.

Third: Prepare a shovel and a cloth to keep out the rain, and the shovel is used to deal with some of the messy concrete during the pouring process. If you don't know anything else, you can go and participate in them pouring concrete.

Experience is worth a thousand words!

The level of the cement grade in the concrete is determined according to the structural design strength of the concrete. Generally, when the design strength of concrete is below zhic30, DAO can be adopted

Use. or marked cement; Equal to more than C30 are used grade cement. In concrete pouring, the main indicators are the workability and slump of concrete, and the workability is related to the proportion of coarse aggregate and fine aggregate mixed into the concrete and the proportion of water to cement.

Answer]: a, b, d

The general provisions of concrete pouring include: Relevant work should be completed before concrete pouring; Before pouring, the concrete feeding list should be checked, the concrete mix ratio should be checked, the concrete strength grade should be confirmed, the concrete transportation time should be checked, the concrete slump should be determined, and the concrete expansion should be measured if necessary, and the concrete should be poured after confirmation; The total time of concrete transportation, pouring and intermittent should not exceed the initial setting time of concrete; In order to prevent the occurrence of segregation, the free height of concrete falling from a height should not exceed 2m, and the limited free height in the vertical structure should not exceed 3m, otherwise the concrete should fall by using a string tube, a slip pipe or a leakage vibrating slide pipe; The temperature of concrete mixture into the mold should not be less than 5, and should not be higher than 35; It is strictly forbidden to add water in the process of concrete transportation, transportation and pouring, and it is strictly forbidden to use the concrete scattered in the process of concrete transportation, transportation and pouring for structural pouring; The mixed tank with rotten concrete should be evenly distributed.

Answer]: Peho d, e

This question is about controlling the quality of concrete construction. The formwork should be moistened before concrete pouring construction, so it is necessary to sprinkle water on the formwork, but there can be no water accumulation before pouring, otherwise the concrete mix ratio (a) will be affected. Concrete slump is a parameter set before construction, and the cause of incompatibility during construction site construction is to find out the reason, adjust the amount of water according to the actual situation of construction, if it is a problem with the design of the mix ratio, it may be necessary to readjust the mix ratio, and can not add water and stir at will (b).

Concrete vibrating is to make the concrete mix uniform, uniform distribution, too long time of vibration will not be conducive to the uniformity and strength of concrete, the general concrete vibrating rod should have a suitable working range (c). Option (e) is a measure to avoid structural failure of the concrete interior when it is not fully condensed; (d) Option is knowledge of concrete curing methods.

Answers]: a, d, e

Item b, the mechanical connection joint in the compression zone and the part of the prefabricated component where the steel bar is less stressed. The welding and binding joint shall not be less than 10d away from the starting point of the steel bar elbow, and shall not be located at the maximum bending moment. C, the surface of the construction longitudinal joint can not be chiseled, but it should be rinsed clean to facilitate the grouting of Kongzhou.

The use of high-pressure water to flush hair, depending on the temperature of the loss, can be carried out 5 20h after pouring; When using a sand gun to flush the hair, it should generally be carried out one or two days after watering.