Crack retardant mixture for cement mortar

摘要

PURPOSE: A shrinkage reducing agent cement composition and a cement mortar finishing member using the same are provided to enhance long term intensity and to prevent cracking due to dry shrinkage. CONSTITUTION: A shrinkage reducing agent cement composition includes cementation ash and fine aggregate at the mass ratio of 1:1-3. The cementation ash comprises 60-90 wt% of normal cement, 5-14 wt% of crack retardant mixture, 0.1-15 wt% of calcium sulfo aluminate, 0.1-15 wt% of hollow silica powder, 0.1-15 wt% of metakaolin, 0.1-10 wt% of mica, and 0.01-3 wt% of hollow acryl powder. The cementation ash additionally includes a water reducing agent, a thickening agent and antifoaming agent. 0.01-2 wt% of the water reducing agent is contained in the cementation ash. 0.01-2 wt% of the thickening agent is contained in the cementation ash. 0.01-2 wt% of the anti-foaming agent is contained in the cementation ash.