1, stirring equipment must be responsible for the special person, before starting the machine must check the quality of raw materials and stirring metering equipment, and refueling test, meet the requirements before feeding and stirring.
2. It must be weighed according to the requirements of concrete mix ratio and the order of sand, cement and stone. The weighing deviation of sand shall not exceed 2%, the weighing deviation of cement shall not exceed 3%, and the weighing deviation of water shall not exceed 1%. During the specific operation, the dry hardness of concrete (cement amount) should also be adjusted according to the situation reflected by the operator of the roller.
3. The mixer can feed after empty starting, add water and stir after feeding, and the net stirring time shall not be less than 50 seconds, but not more than 3 minutes. It is not allowed to stop when stirring (except under special circumstances).
4, winter production, raw materials and water should be preheated, keep the temperature of sand and stone 15-20°C, the temperature of water should not exceed 60°C, the temperature of the mixed concrete should not be less than 10°C.
5, should strictly control the concrete parking time, when the room temperature is above 20°C, the parking time shall not exceed 1 hour, the room temperature is below 20°C should not exceed 90 minutes, such as more than the specified parking time, must be according to the concrete situation appropriate cement re-mixing, adding admixture concrete according to the test situation to determine.
6. Make two sets of test blocks per shift according to the regulations, and indicate the date.
7. The laboratory shall cooperate with the measuring staff to control raw material inspection, measurement, working degree, mixing quality, etc., and record and report.
8. Clean up the mixing equipment, dividing equipment and operating platform after work.