Maintenance method of concrete
Steam method
1. When static stop, the ambient temperature should be kept not lower than 5℃, and the temperature can only be raised after pouring for 4 ~ 6h.
2. The heating rate should not be greater than10℃/h. ..
3. During constant temperature, the internal temperature of concrete shall not exceed 60℃, and the maximum temperature shall not exceed 65℃. Constant temperature curing time should be determined by experiments according to the demoulding strength requirements of components, concrete mixture ratio and environmental conditions.
4. The cooling rate should not be greater than10℃/h. ..
Box beam steam method
1. After concrete pouring is completed, the beam body is sealed with a curing cover, and steam is input to control the humidity and temperature around the beam body. When the temperature is low, input steam to raise the temperature, and after the initial setting of concrete, the bridge deck and the box are stored with water to keep moisture. The heating rate shall not exceed10℃/h; The constant temperature shall not exceed 45℃, the concrete core temperature shall not exceed 60℃, and the individual maximum temperature shall not exceed 65℃. When cooling, the cooling speed shall not exceed10℃/h; When the temperature decreases to a point where the difference between the beam temperature and the ambient temperature does not exceed 15℃, remove the curing cover. The cooling of box girder cavity is slow, so ventilation measures can be taken appropriately. The temperature of all parts in the hood is consistent, and the temperature difference is not more than 65438 00℃.
2. Measure the steam curing temperature regularly and make records. The pressure thermometer is arranged in the inner box span, 4m near the beam end and outside the side formwork. Measure the temperature every 2 hours at constant temperature, and every 1 hour at temperature rise and fall to prevent concrete cracks.
After steam curing, water must be sprayed immediately for curing, and the time shall not be less than 7 days. For concrete poured in winter construction, covering curing should be adopted. When the average temperature is lower than 5℃, it should be maintained according to the winter construction method, and the box girder surface should be sprayed with curing agent.
Health-preserving liquid method
1. Spray film curing liquid is suitable for special-shaped or large-area concrete structures that are not easy to spray curing. In this method, the perchloroethylene resin solution is sprayed on the concrete surface with a spray gun, and a plastic film is formed on the concrete surface after the solution volatilizes, so that the concrete is isolated from the air, the water in it is prevented from evaporating, and the normal hydration is ensured. Some films will age and fall off after curing, otherwise they are not suitable for spraying on the concrete surface to be painted in the future. In summer, the film should be protected from the sun after forming, otherwise it will crack easily. When curing concrete with spraying curing liquid, no leakage shall be ensured.
2. Gray curing agent or transparent material is usually used to cure the concrete surface exposed for a long time. The color of gray curing agent is close to the color of concrete, and it can also paint and add color to the surface. By the end of weathering, its appearance is much better than that of white curing agent. Transparent curing agent is a kind of transparent material, which can't paint concrete, but can only keep its original appearance.
Well, that's the concrete curing method introduced by Bian Xiao. I believe that many people have a certain understanding after listening to the specific maintenance methods introduced by Bian Xiao. Concrete is very common now, and many people build houses with concrete. Concrete curing is more important. After listening to the questions about concrete curing methods introduced by Bian Xiao, you should have a certain understanding of concrete curing methods.