PORTLAND CEMENT FOR PRODUCING ALC AND PRODUCTION OF ALC

摘要

PROBLEM TO BE SOLVED: To keep low viscosity for the time until the foaming is completed after pouring ALC slurry to the frame mold without increasing the kneading water by using a specific amount of hemihydrate gypsum as the gypsum in the cement. SOLUTION: The amount of gypsum in the cement is 20-80 wt.% expressed in terms of SO3. The solubility of hemihydrate gypsum is about 3-4 times of that of dihydrate gypsum at 40-50 deg.C in an ALC slurry. Thereby, when an optimum amount of the hemihydrate gypsum is used, SO42- ion is rapidly fed from the hemihydrate and the surface of CaO.Al2O3 is covered with ettringite, and hardening of the cement is inhibited and increasing of the viscosity is suppressed. Low Blaine high-early-strength portland cement, normal portland cement, high- early-strength portland cement or ultra high-early-strength portland cement is cited as the suitable cement to be used.