Fritz-pak Corporation

Water Conditioner FAQ

Category: Specialty

Q. Why does false set occur in volumetric mixers but not in regular ready mix concrete?

A. False set is a rapid hardening of the concrete shortly after adding water. This false set is not a hard set and in regular ready mix concrete, the extended mixing simply breaks up this false set.

Q. Why does false set occur?

A. In the manufacture of cement, gypsum is added to control the set. The gypsum is normally added in the final milling process. If in the final milling the temperature of the cement gets too hot, the gypsum will dehydrate forming anhydrate or hemihydrate (Plaster of Paris). When water is added the Plaster of Paris hardens very fast and gives the appearance of a false set.

Q. Why doesn't false set happen all the time?

A. False set is more common in the summer time and when cement plants are working at full capacity.

Q. Why it is important to control the false set in volumetric mixers?

A. Because when the false set appears, it is very difficult for the contractor to work the concrete. If excess water or superplasticizer is added to the concrete to reduce the effects, this can cause a weaker concrete or increased cost of admixtures.

Q. Will the Water Conditioner affect the true set of concrete?

A. No.

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