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AssigneesRhone-Poulenc Chimie, Bouygues
InventorsAndre Bertoncini, Jerome Dugat, Laurent Frouin, Jean-Luc Jaquier, Evelyne Prat
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A process for spraying concrete or mortar, by a dry route or by a wet route, in order to produce on a surface a layer of concrete or of mortar. Just before or at the time of spraying, an aqueous suspension (A) of silica and of an aluminum compound chosen from aluminum sulphate, basic aluminum sulphates, alums and mixtures thereof is added to the concrete or mortar. The aqueous suspension (A) has a pH lower than 4, a solids content of between 10 and 50% by weight, and, after a period at rest of 48 hours, is in the form of a gel which is reversible under low shear. The aqueous suspension (A) is effective for increasing the thickness of the sprayed layer and reducing rebound of the concrete or mortar sprayed onto the surface.
A process for spraying a layer of concrete or mortar on a surface, the process comprising steps of:
A process for spraying a layer of concrete or mortar on a surface, the process comprising adding an additive to the concrete or mortar prior to or during spraying of the concrete or mortar, the additive comprising an aqueous suspension A of silica and of aluminum compound chosen from aluminum sulphate, basic aluminum sulphates, alums and their mixtures, the aqueous suspension A having a pH lower than 4 and a solids content of between 10 and 50% by weight, and, after a period at rest of 48 hours, being in the form of a gel which is reversible under low shear, the aqueous suspension A being prepared by a process including mixing, with agitation, of an aqueous suspension B of silica with the aluminum compound in powder form and, optionally, of water, the aqueous silica suspension B being an aqueous suspension B of precipitated silica which has been obtained by mechanical disintegration of a filter cake originating from a silica precipitation reaction.
Dependencies are inferred from the claim text.