Features
1 when mixing concrete in winter, the mixing time must be longer than that at room temperature. Strictly control the feed sequence. Since hot water is used for mixing, it is strictly prohibited to put cement first to prevent false setting of cement and affect the strength of cement.
2, the key to winter construction is to take a variety of insulation measures to control the temperature of the concrete, so before starting, should carefully check the construction of the insulation shed, the laying of the gas pipeline and insulation, in order to reduce heat loss, to ensure the temperature in the shed.
3, because there are more heat sources in the warm shed, the use of cotton felt cloth cover, must strengthen fire prevention, equipped with enough fire equipment. Smoking and open flame work are strictly prohibited in the shed. Safety measures should be taken before welding.
4, the sand, stone and cement used for mixing in winter should be kept at a positive temperature. Use 31.5R or above ordinary Portland cement and store it in a warm shed. The cement should not be in direct contact with hot water above 80 ° C. Cement must not be directly heated. Mixing concrete should be done by adding water, and the water temperature should not exceed 80℃. If the thermal calculation requirements can not be met, the aggregate heating method is used, and the aggregate heating temperature is not more than 50℃. The aggregate must be clean and free of ice, snow and other freezing materials. The mud content shall not exceed the specified value. When adding potassium and sodium ion early strength antifreeze, concrete shall not be added with active aggregate. Sany cylinder manufacturers believe that it is necessary to strictly control the water-cement ratio, and the water-cement ratio is not greater than 0.6. The water in the mixed solution and the water in the mixed solution shall be deducted from the mixed water. During the construction process, the temperature of various materials is measured every hour, and the temperature is controlled at any time to ensure the mold temperature of concrete, requiring the temperature of the concrete cement mixer to be not less than 10 ° C, and the temperature of the concrete into the mold to be not less than 8 ° C.
