Method of controlling the hydration behavior of gypsum in the manufacture of composite materials

摘要

PCT No. PCT/DE94/00718 Sec. 371 Date Mar. 20, 1996 Sec. 102(e) Date Mar. 20, 1996 PCT Filed Jun. 23, 1994 PCT Pub. No. WO95/01942 PCT Pub. Date Jan. 19, 1995A method of controlling the ratio of hydration time (HT) to open time (OT) in the manufacture of composite materials from a mixture containing hydratable calcium sulphate such as gypsum binders, aggregates, fibers, water additives and other additives is disclosed. The method includes adding a retarder-accelerator combination such as Retardan and potassium sulphate to the mixture and applying pressure. The retarder-accelerator combination and application of pressure provide advantageous reduction in the ratio HT:OT. More particularly, HT:OT can be reduced to less than 1.