What should I pay attention to when pouring concrete in rainy days?

No new concrete pouring warehouse surface shall be opened in rainy days above moderate rain, and concrete with impact resistance, wear resistance and plastering requirements shall not be constructed in rainy days.

When pouring in light rain, the following measures should be taken:

1, appropriately reduce the water consumption for concrete mixing and the slump of export concrete, and appropriately reduce the water-binder ratio of concrete when necessary;

2. Strengthen the drainage in the warehouse to prevent the surrounding rainwater from flowing into the warehouse;

3. Do a good job of protecting the surface of fresh concrete, especially the joints.

In the pouring process, in case of heavy rain and rainstorm, the feeding should be stopped immediately, and the concrete that has been put into storage should be covered after vibrating compaction. After the rain, the accumulated water in the warehouse must be removed first, and the parts washed by the rain should be treated immediately. If the concrete can be reshaped, the joint concrete should be resurfaced, otherwise it should be treated as a construction joint. Understand the weather forecast in time and arrange the construction reasonably.

Extended data:

Cao Zuo Jian

1. Concrete layer formwork, steel bar, top embedded parts and pipes have all been installed, which meet the design requirements after inspection, and the concealment and pre-inspection procedures have been handled.

2. Shelves and. After the concrete pouring is completed and passed the inspection.

3. Cement, sand, stone and admixture meet the requirements of relevant standards after inspection, and the laboratory has issued a notice of concrete mixture ratio.

4. The scale (or automatic feeding system) has been tested accurately, and the vibrator (rod) has passed the trial operation.

5. The foreman has conducted comprehensive construction technical training for the operation team according to the construction scheme, and the application for concrete pouring has been approved.

Matters needing attention

1. When concrete is poured into formwork, formwork or steel skeleton shall not be dumped centrally. When the pouring height is greater than 2M, the string tube and chute should be used for discharging, and the free falling height from the discharging nozzle to the pouring layer should not be greater than1.5m.

2. Concrete must be poured within 5 hours (from the start of the train). In order to prevent cold joint during concrete pouring (cold joint refers to the construction quality joint formed when the time interval between the upper and lower layers of concrete pouring exceeds the initial setting time), the concrete pouring time for two times shall not exceed 65438 0.5 hours, and the joint shall be continuously stirred with a vibrating rod.

3. When pouring, the vibrating duration should make the concrete surface appear laitance, no bubbles and no sinking. The insertion points of vibrators are arranged evenly in plum blossom shape, and move in the order of determinant, and the distance of moving position should not be greater than 40CM. Make sure there is no vibration leakage, but no vibration.

4. When pouring beam slab concrete, beam concrete should be poured first, starting from the beam-column joint, so as to ensure the vibrating compaction of the beam-column joint, and then circulating pouring with the slab by grouting method, but no cold joint can occur.

5. When concrete pouring is about to be completed, estimate the remaining concrete quantity and the remaining concrete quantity, and contact the mixing station for reasonable scheduling.

Transportation requirements:

1, in the process of transportation, should maintain the uniformity of concrete, avoid stratification and segregation phenomenon;

2, should be with the least number of running and running time;

3, should guarantee the continuous concrete pouring work;

4. The container for transporting concrete should be tight and leak-free, and the inside of the container should be smooth, smooth and non-absorbent.

The dumping method can be manual or mechanical. It is efficient to transport and pour concrete mixture with concrete pump, which can reach hundreds of cubic meters per hour. Whether it is cast-in-place concrete engineering or prefabricated components, the compactness of concrete after pouring must be ensured. Its method mainly adopts vibration tamping, and some also adopt centrifugation, extrusion and vacuum operation. Fluidized concrete mixed with some superplasticizers cannot be vibrated.

References:

Baidu encyclopedia-concrete pouring