Construction Research & Technology Gmbh

Sika Technology Ag

Mbt Holding Ag

Martin Weibel

Benedikt Lindlar

Terje Angelskar

Montserrat Alfonso

Christian Stenger

Elena Kolomiets

Helmut Gebhardt

The present invention relates to the use of a soluble magnesium compound for adjusting, in particular reducing, the viscosity of an aluminum sulfate suspension.

Aluminum sulfate suspensions with reduced viscosity

The invention concerns an accelerator mixture which contains aluminum in oxidation state 3, sulphate and hexafluorosilicic acid, a process for the preparation of said accelerators and the use of said accelerators for the coating of substrates with concrete or mortar. Furthermore the invention relates to concrete or mortar containing accelerators according to the invention and the hardened layers produced by applying the accelerators to concrete or mortar. The invention relates also to the use of hexafluorosilicic acid as a stabilizer.

Accelerator mixture and method of use

The invention relates to an accelerator, preferably for sprayed concrete or sprayed mortar, which is present as an aqueous mixture, preferably dispersion, particularly preferably suspension, which contains the following: (a) aluminium in oxidation state 3, (b) sulphate, (c) fluoride, and/or (semi)metal fluoro complexes, (d) stabiliser, preferably inorganic stabiliser, particularly preferably magnesium silicate and/or kaolin and/or clay minerals and/or allophane, in particular magnesium silicate and/or bentonite, particularly preferably sepiolite, especially particularly preferably SiMgO(OH)(OH)and/or MgSiO(OH).

Aqueous accelerator mixture

An accelerating admixture for use with cementitious compositions, especially shotcrete, comprises aluminium sulphate and at least one alkanolamine. The admixture also preferably comprises an stabilising agent, which is preferably selected from aqueous stable polymeric dispersions and sepiolite magnesium silicate.

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Zurich, Switzerland

Martin Weibel