abstract |
PROBLEM TO BE SOLVED: To provide a rebound reducing agent which can reduce a rebound rate at the time of spraying and which is used for spraying to a tunnel or the like, a cement concrete using the same, a method for producing the same, and a method using the cement concrete. Provide spraying method. SOLUTION: In particular, polyethylene oxides having an average molecular weight of 1,000,000 to 5,000,000, in particular, an alkyl group having 1 carbon atom. Alkylnaphthalenesulfonic acid formalin condensates, and a rebound reducing agent containing urea as an active ingredient, a cement composition containing cement, and a cement concrete containing the rebound reducing agent, in particular, The spraying method comprises mixing a part of the active ingredient of the rebound reducing agent with the quick-setting cement mixture immediately before spraying. |