Natural conservation can be divided into covering water conservation and plastic film conservation:
(1) Covering and watering maintenance refers to covering concrete with suitable materials such as straw curtains, reed mats, sacks, sawdust, wet soil and wet sand within 3- 12h after concrete pouring, and watering frequently to keep concrete moist.
(2) Plastic film curing refers to covering the concrete with plastic film to separate it from the air, so that the water is not evaporated, and the cement has solidified and hardened through the hydration of water in the concrete.
Natural curing is carried out in the outdoor natural environment (natural temperature and humidity), but the concrete surface should be sprinkled with water or covered with moisturizing materials to prevent water from evaporating from the concrete surface.
Steam curing is to put concrete members in a steam curing room and introduce steam to raise the temperature of concrete, accelerate the hydration and hardening process of cement and auxiliary cementing materials, quickly reach the demoulding strength, and speed up the turnover of formwork and production efficiency.