Mbt Holding Ag

Sandoz Gmbh

Bernhard Leikauf

Salvatore Valenti

Max Oppliger

Akira Ohta

Peter Ellenberger

Josef F Drs

Qiwei Yang

Helmut Gebhardt

Terye Angelskar

Valentina Mader

Admixtures for cementitous compositions

An accelerating admixture for use with spraying cementitious compositions such as shotcrete comprises (a) a compound selected from aluminium hydroxide, aluminium hydroxysulphate and mixtures thereof, and (b) an acidic substance which essentially does not react with the compound. The preferred acid substances are organic acids.

Concrete accelerators

Cement accelerating admixture

An admixture for use in cementitious compostions which are to be applied in consecutive layers consists essentially of a water-soluble polyalkylene oxide and a superabsorbent material. Optionally (and preferably) also present is a plasticiser or superplasticiser, preferably a polyalkylene oxide-modified styrene-maleic anhydride copolymer.

Concrete curing admixtures

A method for coating a substrate with a cementitious composition by spraying, comprising the addition to the initial cementitious mix one of a .beta.-naphthalene sulphonate-formaldehyde condensate and a water-soluble poly(alkylene oxide) of molecular weight from 100,000-8,000,000, the other being added at the spraying nozzle, there being additionally added at the nozzle (preferably as a single component with the other nozzle-added material) an accelerator selected from aluminium sulphate, aluminium hydroxide and aluminium hydroxysulphate. In a preferred embodiment, the material added at the nozzle also contains a superplasticiser.

Cement spraying admixture

A random copolymer corresponding to Formula I in free acid or salt form having the following types and numbers of monomer units; ##STR1## wherein A is selected from the moities (i) and (ii);

Fluidifying agents for cementitious compositions based random

A random copolymer corresponding to Formula I in free acid or salt form having the following types and numbers of monomer units; ##STR1## wherein A is selected from the moieties (i) and (ii);

Organic compounds

A random copolymer in free acid or salt form having the following types and numbers of monomer units; ##STR1## in which M is hydrogen or a residue of a hydrophobic polyalkylene glycol or polysiloxane,

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Linn, Switzerland

Bernhard Leikauf