Method for accelerating the setting of a cement, in particular of sprayable concrete and cement set-accelerator

摘要

In a process to accelerate the drying of air-injected concrete, the process is promoted by two additives admixed separately in two stages. The first additive is admixed shortly before the concrete is injected and consists of 40-90% calcium hydroxide, 5-50 calcium formiate and/or 5-20% wine acid. The second additive is 20-40% aluminium sulphate or aluminium hydroxide sulphate, 5-25% aluminium subsequently admixed is hydroxide, 10-50% water and 5-45% carbonic acid or their salts.