KAKO VZDRŽEVATI BETON TLA V RAZLIČNIH LETNIH ČASIH?
-VANSE Machinery
The current concrete floor is compacted with a concrete laser leveling machine, and there is almost no error. Concrete technology is becoming more and more important. Concrete has developed from the initial low-strength grade and ordinary concrete to today's high-strength grade and high performance. Sometimes the maintenance of concrete is often ignored in engineering construction, causing the surface of the concrete to shrink. , cracking, peeling and other phenomena, in order to make the concrete floor more sustainable and long-term use, it is necessary to pay special attention to the concrete curing method during construction.
1. Cooling measures must be taken during construction, such as choosing to pour at night to avoid direct sunlight, and adjusting the concrete ratio in time.
2. At the same time, it must be noted that the temperature of the concrete formwork must be cooled, because if the temperature of the formwork is too high, the surface of the concrete will lose moisture quickly after pouring, resulting in defects such as sanding on the concrete surface. The maintenance of concrete in this season requires a lot of water, especially for the parts that are not easy to maintain, such as columns, cover beams, and beam webs, they should be tightly wrapped with geotextiles and sprinkled regularly. The surface of the concrete is always in a humid environment. In the early stage of curing, the concrete surface is sometimes dry and sometimes wet, because the strength of concrete that is sometimes dry and sometimes wet is easy to reduce, and it is easy to produce shrinkage cracks. Therefore, within 7 days of concrete pouring, it is necessary to prevent water evaporation and keep the concrete surface moist. In short, the focus of concrete maintenance in this season is moisturizing. If measures such as moisturizing and cooling are done well, problems such as early setting of concrete, plastic cracks, reduction of concrete strength and durability caused by high temperature will not appear.
In the cold season when the temperature is lower than 5 degree , the following measures should be taken for the maintenance of concrete:
1. After demoulding, cover and maintain the insulation.
2. The use of steam curing.
3. Improve the thermal insulation performance of the formwork. Most of the steel formwork used in bridge construction has good thermal conductivity and is easy to lose temperature. Therefore, insulation materials such as straw curtains should be wrapped outside the formwork or measures such as thickened formwork and double-layer formwork should be used.
4. Increase the mixing temperature of concrete. First of all, the heating treatment of the mixing water can be considered, and the aggregate can also be considered to be heated. The purpose is to ensure the initial cement hydration temperature and improve the early strength of the concrete.
If the maintenance of concrete in the early cold period takes the above measures actively, the concrete will be prevented from freezing due to low temperature. After the concrete is frozen, its hydration will stop. After the temperature rises, although it can continue, the surface of the concrete has changed. Crisp, lose strength, and even larger cracks appear. Therefore, it is necessary to especially strengthen the early insulation and maintenance of concrete, and it must not be frozen before the concrete strength reaches 50 percent of the design strength.