Maintenance technology
1. Covering and water conservation
Using the natural conditions that the average temperature is higher than +5℃, the concrete surface is covered with suitable materials and watered, so that the concrete can maintain the appropriate temperature and humidity conditions required for cement hydration for a certain period of time.
Covering water conservation shall meet the following requirements:
(1) After concrete pouring, cover and water conservation shall be carried out within 12h.
(2) The water curing time of concrete mixed with Portland cement, ordinary Portland cement or slag Portland cement shall not be less than 7d, and the water curing time of concrete mixed with retarded admixture, mineral admixture or concrete with impermeability requirements shall not be less than 14d. When other types of cement are used, the curing of concrete should be determined according to the technical performance of the cement used.
(3) The watering frequency should be determined according to the concrete's ability to keep wet.
(4) The curing water for concrete should be the same as that for mixing.
(5) When the average temperature of the day is lower than 5℃, water shall not be sprinkled. Large-area structures such as floors, floors and roofs can be maintained by storing water. The water storage tank project can be cured by water injection after the internal model concrete is removed to a certain strength.
2. Film cloth maintenance
If conditions permit, waterproof and airtight film cloth (such as plastic film cloth) can be used for maintenance. Cover all exposed parts of the concrete surface tightly with film cloth to ensure that the concrete can be fully maintained without losing water.
The advantages of this curing method are no need for watering, simple operation and reusability, which can improve the early strength of concrete and speed up the turnover of molds. However, the condensed water should remain in the film cloth.
3. Film curing liquid curing
When it is inconvenient to water the concrete surface or use plastic film cloth for curing, the method of coating curing liquid to prevent evaporation of water inside the concrete can be used for curing.
The film curing solution curing is to spray the film-forming solution on the concrete surface, and after the solution volatilizes, it condenses into a film on the concrete surface, so that the concrete surface is isolated from the air, and the water in the closed concrete no longer evaporates, thus completing hydration. This maintenance method is generally suitable for concrete construction with large surface area and water shortage.