2. The heat storage method is generally applicable to the temperature above-10℃, and the greenhouse method is applicable to the temperature below-10℃. Thermal storage method is to use the material with low thermal conductivity on the outer surface of concrete pouring block for thermal insulation, and the heat source is the heat pre-applied to concrete components and the hydration heat of cement. The formwork used in construction shall be thermal insulation formwork, and the top surface of the poured concrete shall be immediately covered with thermal insulation materials. The thermal storage method is essentially a surface insulation method, which is consistent with the surface protection of concrete dams in form. But their purposes and requirements are different. The purpose of surface protection is to prevent concrete surface cracks, and the temperature difference between the inner and outer surfaces of concrete is required not to exceed the allowable standard. The purpose of heat storage method is to prevent the freezing injury of concrete surface, and the surface temperature of concrete is required to be not lower than its normal solidification and hardening temperature.

3. The greenhouse method is to build a greenhouse at the concrete pouring position. Greenhouse is usually heated by steam exhaust pipe or heater, so that the temperature in the greenhouse is kept at about 0 ~ 5℃. Greenhouse is mainly composed of shed cover, supporting structure and enclosure structure of insulation layer. We usually adopt three types. Binding greenhouse is a simple greenhouse. Supported by 10× 10cm precast concrete column, the height is 3.5 ~ 4. Hmm. The shed cover is tied with logs on site. The insulation layer is made of straw curtain, straw mat and canvas. The concrete outlet at the top of the shed is provided with a movable material cover, and the straw mat is wrapped in sacks for insulation. Assembled greenhouse, its roof is assembled by a single steel truss. Because of the large span, the supporting structure can be arranged outside the formwork. The roof must also be equipped with a concrete discharge port and a movable material cover. Assembled greenhouse mainly includes steel truss composite beam, shaped insulation support structure, hoisting structure and enclosure structure. The whole shed cover is an integral hoisting unit. Its main advantage is convenient installation and disassembly. To sum up, different construction methods are adopted for concrete construction in winter according to different temperatures, so that the quality standard of concrete construction can be met according to the changes of concrete strength grade, structural thickness, construction season and maintenance conditions.