After concrete pouring, if the climate is hot and the air is dry, the water in the concrete evaporates too quickly, which leads to dehydration, so that the cement particles that have formed gel can not be fully hydrated, can not be transformed into stable crystals, and lack sufficient cohesive force, thus causing the concrete surface to fall off in flake or powder.
In addition, when concrete does not have enough strength, premature evaporation of water will also produce large shrinkage deformation and drying cracks. Therefore, the initial curing after concrete pouring is very important. Concrete should be cured immediately after final setting, and hard concrete should be cured immediately after pouring.
Nature conservation:
During the curing period of formwork concrete, measures such as formwork wrapping, watering and sprinkling should be taken to keep moisture and moisture, so as to ensure that formwork joints are not dehydrated and dry. In order to ensure the smooth form removal, the formwork can be loosened slightly after 24 ~ 48h of concrete pouring, and water conservation can be continued until the form removal, and then the moisture can be kept to the specified age.
After the concrete surface protective layer is removed or the formwork is removed, measures such as storing water, watering or covering with water should be taken to wet cure the concrete. When the concrete surface is wet, bare concrete can be quickly covered or wrapped with linen, straw curtains and other materials, and then wrapped with plastic sheets or canvas with linen, straw curtains and other moisturizing materials.
During coating, the coating materials should be intact and completely overlapped with each other, and there should be condensed water droplets on the inner surface. In areas where conditions permit, the coating and moisture curing time of concrete should be extended as much as possible.