Regulations to be observed in the use of cold rooms in civil cold storage

Regulations to be observed in the use of cold rooms in civil cold storage

1. Pozzolanic cement and slag cement mixed with pozzolanic materials shall not be used in the cold room of civil construction cold storage; different types of cement shall not be mixed, and two types of cement shall not be used for the same component.

2. Civil construction cold storage freezing rooms, frozen objects cold storage rooms, ice storages, negative temperature tunnels, etc. should be given priority to use ordinary Portland cement higher than 425, and slag cement higher than 425 may also be used; cooling rooms and cold storage The room should use ordinary Portland cement or slag cement higher than No. 325.

3. The strength level of concrete used in the cold room of civil construction cold storage shall not be lower than C20. When preparing concrete, the water-cement ratio shall not be greater than 0.60, and the amount of cement per cubic meter of concrete shall not be less than 275kg; the strength level of concrete used in the freezing room shall not be lower than C30. The water-cement ratio shall not be greater than 0.60, and the amount of cement per cubic meter of concrete shall not be less than 300kg.

　　Note: The concrete on the ground surface of the cold storage must be smooth.

　　 Fourth, the frost-resistant grade of concrete used in the cold room of civil cold storage should not be less than D50. Appropriate amount of concrete admixtures can be mixed to improve the ability of concrete to resist freeze-thaw damage.

　　Note: The frost-resistant label D50, that is, the 28d-old test piece undergoes 50 freeze-thaw cycles, and its strength loss rate should not exceed 25%, and the weight loss rate should not exceed 5%.

　　 5. The brick masonry in the cold room of the civil cold storage should be made of clay bricks with a strength grade of not less than MU10, and cement mortar should be used for masonry and plastering. The strength grade of cement mortar for masonry shall not be lower than M7.5.

　　 6. In civil cold storage, no admixtures that have corrosive effects on steel bars shall be used in the concrete of the reinforced concrete structure in the cold room. The amount of alkali in the admixture should comply with relevant regulations.

　　 Seven, the reinforced concrete bearing steel bar in the cold room of the civil cold storage should adopt the Ⅰ and Ⅱ grade hot-rolled steel bars. 8. After the ground of the civil cold storage is ready, it needs to be watered and maintained for 7-10 days. The first time the temperature cannot be lowered below 4 ℃ when it is turned on for the first time, keep it at 4 ℃ for one day, and then lower the temperature to 0 ℃, keep it warm 2 -3 days, cool down to -1°C again, keep warm for one day, cool down to -3°C again, keep warm for one day, cool down to -5°C again, keep warm for one day, and then cool down to -18°C as above before it can be used normally.