concrete spraying process and mixture used.

The invention relates to a method for improving the shotcrete rebound properties comprising incorporating therein a microscopic silica powder which was treated at first rate of 2 to 25% of its weight with a selected liquid from water, an alkanolamine, a polyol and an aqueous solution of at least one material selected from a concrete additive, an alkanolamine, a polyol and a cellulose compound soluble in water, this method is particularly applicable to the process dry spraying.