Concrete Knowledge 100 Questions (11)

61, why are there three lines in each production mix, and how should they be used?

A: A theoretical mix ratio of behavior (that is, the water content of sand and stone is zero) is used by some stations. 

The production mix used by the two acts of dry days. The mix ratio used on rainy days and after rain.

62. Can the mix ratio used for pavement or pile foundation be used for other parts?

A: No. Because the pavement or pile foundation mix is specifically designed for its technical requirements, it is not suitable for other parts.

63, why to limit considerable water consumption?

A: Because when the weather is very dry, the water content of the sand may be less than 4%, then the considerable water consumption 

per cubic meter of concrete can be increased by 10kg according to the dry day production water consumption, if it is not up to the slump 

requirements, it may be the pumping agent water reduction rate is too small, then the pumping agent content should be increased by 0.1% 

to 0.2%. Water consumption cannot be increased blindly in order to meet slump requirements.

64, under what circumstances to use the narrow wall mix?

A: When the shear wall structure is encountered, the narrow wall mix ratio should be used when the shear wall or wall beam 

plate is poured together. Because the shear wall is relatively narrow (mostly 200mm thick), minus the four layers of wall reinforcement 

and three beam reinforcement, the net distance between the reinforcement is about 3~100px, the concrete is not easy to pour when it is slightly dry,

and the mix ratio of the narrow wall increases some fine stone particles, which is easy to pour.

65, why should we give priority to the blending ratio of mineral powder?

A: Because the incorporation of the appropriate amount of mineral powder in the concrete has little effect on the performance of the concrete, 

it can replace the cement in the same amount and reduce the production cost. The content of 20% ~ 25% is better, too much will cause slow coagulation, 

and increase the shrinkage of concrete. In winter construction is quite good little or no blending.

66, what regulations do the production controller have for adjusting the water consumption of concrete?

A: Allow to increase the water consumption by 5kg according to the production mix, and reduce the production water consumption

is not limited (as long as the concrete can ensure that the slump of the factory meets the site requirements). When the water consumption 

is increased by more than 5kg, it must be reported to the laboratory director for approval.