Concrete mix from water mixing to start to set (initial setting time) generally in four or five hours, the initial setting time of cement about three hours (cement variety, temperature, plus the greater impact on its), after the initial setting time, the mixture began to harden, pouring down the concrete will cause serious quality accidents; How long can the concrete in the pump car stay, see when you start mixing, start from the water, a few hours pouring is better, if long distance transportation, in traffic jams on the road, it is trouble, must rush to pour down before the initial setting, three hours or so in summer, winter can not more than four hours.
