Abstract: The invention concerns a process for the preparation of a hardening accelerator composition by reaction of a water-soluble calcium compound with a water-soluble silicate compound and by reaction of a calcium compound with a silicon dioxide containing component under alkaline conditions, in both cases the reaction being carried out in the presence of a polycondensate containing at least one structural unit consisting of an aromatic or heteroaromatic moiety bearing a polyether side chain and at least one structural unit consisting of an aromatic or heteroaromatic moiety bearing at least one phosphoric acid ester group and/or its salt. The invention concerns a composition of calcium silicate hydrate and the polycondensate, its use as hardening accelerator and for the reduction of the permeability of hardened compositions.

Abstract: The invention concerns a process for the preparation of a hardening accelerator composition by reaction of a water-soluble calcium compound with a water-soluble silicate compound and a process for the preparation of a hardening accelerator composition by reaction of a calcium compound with a silicon dioxide containing component under alkaline conditions, in both cases the reaction of the water-soluble calcium compound with the water-soluble silicate compound being carried out in the presence of an aqueous solution which contains a water-soluble comb polymer suitable as a plasticizer for hydraulic binders. The invention concerns also a composition of calcium silicate hydrate and comb polymer, its use as hardening accelerator and for the reduction of the permeability of hardened compositions.

Abstract: A process for the preparation of a copolymer in semicontinuous operation in a polymerization apparatus including a polymerization reactor connected to a metering device, acid monomer being initially taken in the metering device and polyether macromonomer and water in the polymerization reactor, acid monomer being metered from the metering device via an acid monomer metering line into the polymerization reactor, a portion of the copolymer-containing aqueous medium being passed continuously during the free radical polymerization from the polymerization reactor via a reaction mixture line which is connected via a mixing device to the acid monomer metering line, the discharged copolymer-containing aqueous medium being mixed with the acid monomer in the mixing device during the metering of the acid monomer and being recycled to the polymerization reactor after the mixing via the acid monomer metering line.

Abstract: The invention concerns a process for the preparation of a hardening accelerator composition by reaction of a water-soluble calcium compound with a water-soluble silicate compound and by reaction of a calcium compound with a silicon dioxide containing component under alkaline conditions, in both cases the reaction being carried out in the presence of a polycondensate containing at least one structural unit consisting of an aromatic or heteroaromatic moiety bearing a polyether side chain and at least one structural unit consisting of an aromatic or heteroaromatic moiety bearing at least one phosphoric acid ester group and/or its salt. The invention concerns a composition of calcium silicate hydrate and the polycondensate, its use as hardening accelerator and for the reduction of the permeability of hardened compositions.

Abstract: The present invention relates to a process for the preparation of a copolymer in semicontinuous operation in a polymerization apparatus, comprising a polymerization reactor connected to a metering device, in each case acid monomer being initially taken in the metering device and polyether macromonomer and water in the polymerization reactor, acid monomer being metered from the metering device via an acid monomer metering line into the polymerization reactor, free radical polymerization initiator being passed into the polymerization reactor before and/or during the metering of the acid monomer into the polymerization reactor so that an aqueous medium in which acid monomer and polyether macromonomer are reacted with formation of the copolymer by free radical polymerization forms in the polymerization reactor, a portion of the copolymer-containing aqueous medium being passed continuously during the free radical polymerization from the polymerization reactor via a reaction mixture line which is connected via a mi

Abstract: The invention concerns a process for the preparation of a hardening accelerator composition by reaction of a water-soluble calcium compound with a water-soluble silicate compound and a process for the preparation of a hardening accelerator composition by reaction of a calcium compound with a silicon dioxide containing component under alkaline conditions, in both cases the reaction of the water-soluble calcium compound with the water-soluble silicate compound being carried out in the presence of an aqueous solution which contains a water-soluble comb polymer suitable as a plasticizer for hydraulic binders. The invention concerns also a composition of calcium silicate hydrate and comb polymer, its use as hardening accelerator and for the reduction of the permeability of hardened compositions.