在混凝土或砂浆硬化过程中,利用聚氯乙烯薄膜复盖其表面,由于可以防止水分蒸发,使制品在硬化期仍保持相当的湿度,因而水泥颗粒水化充分,可提高其早期强度5～20%。在钢筋混凝土制品工厂中,将振动成型好的制品四周用绳团团包住,表面复盖聚氯乙烯薄膜,这样进行蒸汽养护,混凝土强度增长比 During the hardening process of concrete or mortar, the surface of the concrete is covered with a polyvinyl chloride film. Since moisture can be prevented from evaporating, the product still maintains a relative humidity during the hardening period, so that the cement particles are fully hydrated and the early strength thereof can be improved by 5 to 20 %. In the reinforced concrete product factory, the vibrated product is surrounded by a rope and the surface is covered with a polyvinyl chloride film, so that steam curing is performed, and the strength of the concrete is increased.