The concrete construction in winter construction should be pre-made in winter construction organization plan and preparation work, and measures such as snow prevention and anti-freezing should be taken in advance for all materials and facilities. During construction in winter, concrete prepared with Portland cement or ordinary Portland cement shall not be frozen when the compressive strength reaches 40% of the design strength and is not less than 5 MPa. Safety measures such as fire prevention, antifreeze and gas poisoning should be formulated during construction in winter.
When pouring concrete, admixtures such as air entraining agent and air-entraining water reducing agent are added to improve the freezing property of the concrete. The temperature of each material of the mixed concrete should meet the temperature required for the concrete mixture to be agitated and synthesized. When mixing concrete in winter, the aggregate shall not carry ice and snow and freeze agglomerates, strictly control the mix ratio and slump of concrete; before mixing, the mixer should be flushed with hot water. The order of feeding: firstly aggregate and water are stirred, and cement is added. The stirring time should be 50% longer than the normal temperature. The outlet temperature of the concrete mixture should not be lower than 10 °C, and the mold temperature should not be lower than 5'C.
Technical requirements for concrete transportation and pouring: The concrete transportation time should be as short as possible, and the container for transporting concrete should have insulation measures. Before the concrete is poured, the snow, snow or dirt on the formwork, steel bars shall be removed, and the temperature for forming and curing shall be prepared. The heat storage method shall not be lower than the lot; the steam method shall not be lower than 50C; the thin structure shall not be lower than 8C.