Abstract: Described are polymers and cement admixtures which reduce drop in fluidity with time. Said admixture comprises at least one polymer of the present invention and at least one polymer A. The polymer of the present invention comprises side chains of which at least 10 weight-% can be cleaved in alkaline medium. The polymer of the present invention is an acrylic polymer which comprises side chains connected to the backbone by ester linkages. These side chains may be alkyl, hydroxy alkyl, cycloalkyl or polyoxyalkylene groups. Polymer A is a cement dispersing agent. The combination of polymer A with the polymer of the present invention in a weight ratio of 0.1:10-10:1, and preferably 1:10-10:1 reduces the drop in fluidity with time of cementitious compositions.

Abstract: Described are polymers and cement admixtures which reduce drop in fluidity with time. Said admixture comprises at least one polymer of the present invention and at least one polymer A. The polymer of the present invention comprises side chains of which at least 10 weight-% can be cleaved in alkaline medium. The polymer of the present invention is an acrylic polymer which comprises side chains connected to the backbone by ester linkages. These side chains may be alkyl, hydroxy alkyl, cycloalkyl or polyoxyalkylene groups. Polymer A is a cement dispersing agent. The combination of polymer A with the polymer of the present invention in a weight ratio of 0.1:10–10:1, and preferably 1:10–10:1 reduces the drop in fluidity with time of cementitious compositions.

Abstract: Polymers for cement dispersing admixtures, which show different performing properties in concrete are described. All polymers are based on a composition of reactants, namely a) a poly(acrylic acid), b) a polyalkyleneglycol-monoalkylether and, optionally c) a ?-amino-polyalkylene-glycol-?-alkylether and/or d) a primary or secondary amine. By keeping the composition of reactants constant and varying only the reaction time, polymers with different properties can easily be achieved. Such polymers are suitable for pre-cast, readymix or for increasing workability over time, just depending on reaction time. Polymers of the invention can be used as single polymer or in polymer blends. For this, the kinetics of the used polymer analogous condensation reaction was intensively studied. Additionally, the benefit of amines as reactant regarding stability and hydrolysis velocity of cleavable side groups was investigated.

Abstract: The present invention provides methods and compositions for the reduction of the corrosion rate of already corroding steel reinforcements embedded in a hardened concrete structure as well as for the protective corrosion inhibition of uncorroded steel reinforcements embedded in a hardened concrete structure exposed to aggressive environments. The inventive new compositions employed for the novel method are essentially based on one or more amino- and/or hydroxyalkylamino compound(s), which are partially or completely neutralized with one or more inorganic acid(s) and/or derivatives thereof and/or aliphatic carboxylic- and/or aromatic carboxylic acid(s), one or more surfactant(s) and one or more water-based or water-thinnable water repellent agent(s) selected from the group of organosilicones.

Abstract: On object of the present invention is an agent for the reduction of the degree of shrinkage in hydraulic binders, whereby said comprises an alkanolamine of formula R—NH—(AOH) wherein R is hydrogen or a linear or branched aliphatic or cyclic C1-C6-alkyl group, and A is a C2H4-group or C3H6-group, alone or in combination with hydroxy compounds and/or ethers. Furthermore a method for the reduction of the dry shrinkage of binders such as cement, admixed cement, puzzolanas and thereof produced mortars and concretes by means of such a shrinkage reducing agent is described.

Abstract: A multipurpose cement dispersing, shrinkage compensating and anticorrosive polymer and an admixture comprising said polymer, which improve the workability and the early strength development of fresh concrete, are described. Said polymer is an ester- and amid group-modified acrylic polymer, obtainable by aqueous solution radical copolymerization of (1) acrylic or methacrylic acid with (2) an acrylic or methacrylic methoxy-polyalkyleneglycolester monomer having 2 to 300 moles of an oxyalkylene group each having 2 to 3 carbon atoms, (3) optionally an acrylic or methacrylic methoxy-polyalkyleneglycolamide monomer having 2 to 300 moles of an oxyalkylene group each having 2 to 3 carbon atoms, (4) an acrylic or methacrylic ester of a tertiary aminoalkanol and (5) optionally an acrylic amide of a primary or secondary aliphatic, cycloaliphatic or aromatic amine.

Abstract: Described are setting and hardening accelerators for hydraulic binders and said binder comprising compositions that are free of alkali metals and chlorides. The setting and hardening accelerators comprise, as main component, water-soluble fluoride comprising aluminum salts and water-soluble sulfate comprising aluminum salts, as well as optionally complexing agents and/or amines. In comparison with alkaline accelerators, said mixtures result in an essential shortening of the setting time and a fast development of compressive strengths.

Abstract: Described are liquid setting and hardening accelerators for hydraulic binders and such binder comprising mixtures that preferably are alkali-free and chloride-free and that do not comprise any basic features. The setting accelerators comprise as components aluminum salts, complexing agents, corrosion inhibitors and optionally inorganic and/or organic thickening or thixotropic agents. In comparison with the use of alkaline accelerators, an essential reduction in the setting time and a faster development of high compressive strengths is achieved by the accelerators of the present invention. In comparison with commercially available alkali-free accelerators solid precipitates of aluminum salts and thereby generated plugging up of the spray nozzles is avoided and the corrosion at the spraying devices is eliminated. Said advantages result in a great economic advantage due to less maintenance needed for the devices and less interruptions of work.

Abstract: The present invention provides methods and compositions for the reduction of the corrosion rate of already corroding steel reinforcements embedded in a hardened concrete structure as well as for the protective corrosion inhibition of uncorroded steel reinforcements embedded in a hardened concrete structure exposed to aggressive environments. The inventive new compositions employed for the novel method are essentially based on one or more amino- and/or hydroxyalkylamino compound(s), which are partially or completely neutralized with one or more inorganic acid(s) and/or derivatives thereof and/or aliphatic carboxylic- and/or aromatic carboxylic acid(s), one or more surfactant(s) and one or more water-based or water-thinnable water repellent agent(s) selected from the group of organosilicones.

Abstract: One object of the present invention is an agent for the reduction of the degree of shrinkage in hydraulic binders, whereby said agent comprises an alkanolamine of formula R—NH—(AOH) wherein R is hydrogen or a linear or branched aliphatic or cyclic C1-C6-alkyl group, and A is a C2H4-group or C3H6-group, alone or in combination with hydroxy compounds and/or ethers. Furthermore a method for the reduction of the dry shrinkage of binders such as cement, admixed cement, puzzolanas and thereof produced mortars and concretes by means of such a shrinkage reducing agent is described.

Abstract: A new category of multi-purpose polymers is presented, the polymers being capable to serve as a cement dispersing agent and which at the same time are set-accelerating and do have shrinkage reducing- and anticorrosive properties to steel. The polymers are ester and amide group-modified acrylic polymers, obtainable by a polymer analogous esterification of a polyacrylic acid with 1) a monofunctional polyalkyleneglycol-monoalkylether, 2) a tertiary alkanolamine and optionally 3) by amidation with a amino-polyalkylenglycol alkylether. The multi-purpose polymers serve for cement dispersing admixture for concrete with set accelerating, shrinkage compensating and anticorrosive properties to steel.

Abstract: The invention relates to a setting- and hardening-accelerator for hydraulic binders containing at least a nitrate- or sulfite component, at least a thio-cyanate component, at least an alkanolamine component and at least a carboxylic acid component, as well as a method of setting- and hardening-acceleration of hydraulic binders or mixtures containing hydraulic binders.