crack retardant mixture for cement mortar and cement mortar by using it for heating flooron-dool

摘要

PURPOSE: A shrinkage reducing agent for cement mortar is provided, which prevents an early crack, and has a high expression rate of lunar compression strength. Compounds thereof mixed with sands in different mixing ratios according to seasonal characteristics. A cement mortar composition for ondol finish plastering is also provided using the shrinkage reducing agent. CONSTITUTION: A shrinkage reducing agent for cement mortar comprises: 10-30 wt.% of calcium oxide, 20-40 wt.% of gypsum, 10-20 wt.% of fly ash, combustibles of oilcoke. Cement mortar for ondol finish plastering consists of: 15-30 wt.% of shrinkage reducing agents comprising 70-85 wt.% of cement, 10-30 wt.% of lime, 20-40 wt.% of gypsum and 10-20 wt.% of fly ash, and sands of not less than 2.8 F.M.