Cement will not crack after a few days of curing.
After the cement is solidified, it needs to be watered for more than 3 days. According to the weather temperature, spring and summer should last at least 3 days, which is normal in one week. In autumn and winter, especially in winter, direct contact of water with cement surface should be avoided. Watering after film mulching and curing for about a week. In the final analysis, the function of watering is actually to replenish water. Hydration is a chemical reaction, which makes various components of concrete react and closely combine together to meet the strength requirements.
Theoretically, the wetter the place, the longer the time, the higher the strength of concrete. Another function is to dissipate heat. When concrete is hydrated, its internal high temperature can reach above 60 degrees. Ordinary thermometers can explode instantly, and water can take away the heat emitted from the concrete surface through evaporation. Excessive hydration heat will lead to cracks in concrete.
Does the poured concrete need warranty? Initial setup? This process is probably within a few days after pouring, and watering begins after initial setting. The key point of watering is large area and high frequency. If it is watered in this high temperature and insolation weather, it is recommended to water it for a long time and as many times as possible, because the temperature can make the water evaporate quickly.
Misunderstanding of cement maintenance
1. After concrete pouring and molding, it must be covered with water to meet the requirement of keeping the concrete surface moist for a certain period of time. At the same time, in order to prevent the rapid evaporation of curing water, it should be covered with plastic film, sacks or straw bags. However, the maintenance of concrete is not only watering, but also contains extensive and profound contents.
2. To sum up, there are two main points: one is to keep the concrete moist enough in a certain period of time to meet the needs of cement hydration; Second, it is necessary to ensure that the concrete can maintain an appropriate temperature, an appropriate internal and external temperature difference and an appropriate temperature difference between the surface and the surrounding atmosphere under different environmental temperature conditions, and at the same time, it should have an appropriate cooling rate and heating rate. .
3. The Code for Quality Acceptance of Concrete Structure Engineering (hereinafter referred to as "Quality Code") stipulates that the concrete shall be covered with moisture curing within 12h after pouring. However, many construction workers misunderstand that the latest time to start watering and curing after concrete pouring is 12h, that is to say, as long as watering and curing are carried out after concrete pouring and before 12h, it will meet the specification requirements. Therefore, the construction site often urges technicians to maintain and water, but some people will say that the concrete pouring has only been a few days, and it is still far from 12h! Don't worry.
For the problem that cement will not crack after a few days, the answer has been written for everyone. After the cement is solidified, it needs to be watered for more than three days, and it needs to be cured for at least three days in spring and summer, and it will not crack for about a week. So pay more attention to this aspect of maintenance. Not only that, we also see what is the misunderstanding of cement conservation in the article.