2. The pouring thickness of each layer shall not exceed 450 mm (380 *1.25 = 475 mm ≈ 450 mm).
3. If the concrete is poured in layers, the upper concrete should be vibrated before the initial setting of the lower concrete (the pouring time interval between the two layers should not exceed 3 hours), and the vibrating rod should be inserted into the lower concrete by 5cm to ensure the close combination of the upper and lower concrete.
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4. The arrangement of vibrating insertion points can be determinant or staggered. Generally, each point is vibrated for 20~30s until the concrete no longer sinks obviously and bubbles no longer appear, and the surface is radiant with mortar. The spacing between insertion points shall not be greater than 1.5 times the action radius of the vibrator, that is, 500mm(380* 1.5=570mm is about 500mm).
5. "Slurry flushing method" should be adopted for slab pouring, that is, the beam should be poured from one end first, and then poured together with the concrete of the pile cap when the beam reaches the bottom position of the pile cap.
6, mass pumping concrete after vibrating surface cement slurry is thick, easy to cause surface cracks. First of all, it is required to control the vibrating time when vibrating the top concrete, and pay attention to avoid producing too thick laitance layer on the surface; After the concrete is cast, the redundant laitance layer shall be scraped off with a 2m-long ruler in time, and the concrete surface shall be leveled according to the elevation control points. The pitted part must be filled with concrete. When the concrete slurry is close to the initial setting, the concrete surface should be polished for the second time and carefully wiped twice with wooden crabs. The smoothness of concrete must be ensured, and the shrinkage and dehydration cracks on its initial surface should be closed. In the process of concrete slurry collection and solidification construction, except concrete construction personnel, they are not allowed to walk on the undried concrete surface at will, and the surface after slurry collection must be covered with film in time.
7, to do a good job of concrete heat preservation and maintenance. If film covering method is adopted: after concrete pouring 12h, cover with covering and sprinkle water to keep moisture. Two layers of film and two layers of straw bag are used for curing and covering, and 1 layer plastic film and 1 layer straw bag are prepared on site as standby materials for heat preservation and moisture retention. It is required that the film lap joint should not be less than 150mm and the thermal insulation straw bag lap joint should not be less than 100 mm ... Special attention must be paid to thermal insulation measures in the narrow space between wall column steel dowel, which can be covered with strip film first and then with thermal insulation straw bag to ensure the thermal insulation of weak links of wall column steel dowel.
8, concrete pouring should be continuous, pouring concrete, should check the concrete slump at the scene, and make records. In the process of operation, collision between steel bars and embedded parts should be avoided as far as possible.
Vibration points:
1, insert quickly and pull slowly, so as not to leave gaps in the concrete.
2. The vibrating time for each insertion is about 20-30 seconds, and the concrete will no longer sink obviously, and there will be no bubbles, which will be subject to the beginning of pan-grouting.
3. The vibrating time should not be too long. If it is too long, sand and cement slurry will separate, stones will sink, and a sand layer will be formed on the concrete surface, which will affect the quality of concrete.
4, vibrator should be inserted into the lower concrete 10cm, in order to strengthen the combination of upper and lower concrete.
5. The spacing before and after vibrating insertion is generally 30-50 cm to prevent vibration leakage.
6. Three noes: First, don't touch the formwork when vibrating; second, when vibrating near the formwork, tap the formwork with a wooden hammer at the same time, and use iron brazing at the rebar and the four corners of the formwork.