The Nature Conservancy can be divided into two kinds of conservation and water conservation covered with plastic film .
( 1 ) water conservation is generally covered with suitable material should straws , Luxi , sacks , sawdust, clay and concrete covered with wet sand after concrete pouring is completed within 3-12h according to the outside temperature , and regular watering to maintain moist. Concrete water conservation date of portland cement, slag cement and Portland cement concrete mixing shall not be less than seven days and nights. ; Mixed with retarding admixtures or impermeability of concrete required , not less than 14 days and nights ; When using alumina cement , not less than three days and nights. The number of daily watering already has enough to keep the concrete wet state is appropriate, when the temperature at 15 ° C or more, the concrete pouring in after the three days and nights , daytime watering at least once every three hours , it should be watered at night twice , after conservation , the daily watering of at least about 3 times ( of course, when the temperature of the drying time can be appropriate to increase the frequency of watering ) .
For a large concrete area ( or volume ) should be used " water conservation" for a class of tanks available water conservation project in the mold removal , concrete reaches a certain intensity ; for underground structures or foundation , the surface can be renewed brushing bitumen emulsion or backfill with soil to replace sprinkler maintenance .
( 2 ) refers to the conservation of plastic film plastic film covering the concrete Wei apart with air , water does not evaporate , cement concrete by moisture condensation has been reached to complete the hydration hardening . This method can directly pull the plastic mold covering the surface of the concrete , or plastic emulsion sprayed on the surface of concrete structures will wait until after the emulsion volatile , combined into the concrete surface layer of plastic film , to make concrete structures with air isolated, so that no evaporation of water in the concrete and complete hydration . Spray plastic film 28d conservation drawback is the low concrete strength of about 8% , and because the thin film can not fully meet the insulation , every frozen effect, so in the summer , when this method is used to add sunscreen facilities (no less than 24h), otherwise it will lead to cracks in the concrete to produce filaments .
Overall, the Nature Conservancy low cost, good effect, but the conservation of a long period, in order to shorten the curing period , improve the utilization of the template turnover and venues generally suitable for the production of prefabricated heat when curing .