Abstract:
The present invention relates to a polycarbonic acid-based cement dispersant, a method for preparing the same, and a mortar-concrete admixture using the polycarbonic acid-based cement dispersant.The cement dispersant of the present invention and the mortar-concrete admixture using the cement dispersant are applied to a cement composition such as a cement paste, mortar, concrete, etc., enhance a dispersion and retention force between cement molecules, have excellent fluidity due to the suppression of slump loss, and have an effect of improving workability, such as shortening a concrete mixing time by 20% or more. Further, the mortar-concrete admixture using the cement dispersant of the present invention has an effect of providing a very good concrete condition and an appropriate compressive strength over time.
Abstract:
This invention relates to a method for preparing a star-shaped polycarboxylate superplasticizer by the first esterification step with polyol and (meth)acrylic acid as main reactants and the second polymerization step. In the first step, the star-shaped polymerizable active ends were synthesized by esterification between polyol and (meth)acrylic acid in the presence of catalyst. In the second step, the final star-shaped polycarboxylate superplasticizer was prepared by radical polymerization among the product obtained in first step, unsaturated polyoxyethylene ethers, molecular weight regulator and unsaturated carboxylic acid in the presence of initiator. The production process of this invention exhibits some characteristics including simple, easily controllable, high polymerization degree, low cost and pollution free. The star-shaped molecular structure of polycarboxylate superplasticizer can be achieved through synthesizing active “core” by esterification and “arm” by radical polymerization. It showed better cement paste fluidity and fluidity retention, which manifested as better adaptability to cement and application performance in concrete, than both traditional linear and comb-shaped polycarboxylate superplasticizer at common or lower dosage.
Abstract:
A non-ionic polyether-polyester copolymer for extending workability to a cementitious mixture containing hydraulic cement and water, wherein the copolymer includes residues of at least the following monomers: Component A including an ethylenically unsaturated carboxylic acid ester monomer having a moiety hydrolysable in the cementitious mixture, wherein the hydrolyzed monomer residue has an active binding site for a component of the cementitious mixture; and, at least one of: Component B including an ethylenically unsaturated, carboxylic acid ester or alkenyl ether monomer having at least one C2-4 oxyalkylene side group of about 1 to 30 units; or, Component C including an ethylenically unsaturated, carboxylic acid ester or alkenyl ether monomer having at least one C2-4 oxyalkylene side group of 31 to about 350 units; wherein the molar ratio of Component A to the sum of the molar ratios of Component B and Component C is about 1:1 to about 10:1.
Abstract:
The invention relates to a method and system for monitoring and adjusting both air content and rheology (e.g., slump, slump flow) properties of a hydratable concrete mix contained within a concrete mixer. The system simultaneously tracks dosage of both rheology-modifying admixture (e.g., polycarboxylate polymer cement dispersant) and air control agent or “ACA” (e.g., air entraining agent) by reference to at least four nominal dose response (“NDR”) curves or profiles, which at least four NDR profiles are based on the respective behaviors of each of the ACA and rheology-modifying agent on air content and rheology.
Abstract:
Preparing a non-ionic copolymer having a hydrolysable monomer residue and a polyether macromonomer residue in a semicontinuous mode in a polymerization reactor associated with a metering device, including introducing polyether macromonomer and water into the reactor, wherein hydrolysable monomer which is added thereto forms a polymerization reaction mixture; introducing hydrolysable monomer into the metering device; adding hydrolysable monomer into the reactor from the metering device; passing a free radical polymerization initiator into the reactor before and/or during the addition of the hydrolysable monomer, the hydrolysable monomer and the polyether macromonomer reacting by free radical polymerization to form the non-ionic copolymer; and, subjecting the reaction mixture to polymerization while an addition rate of the hydrolysable monomer and/or at least a component of the polymerization initiator is varied stepwise or continuously. No monomer is introduced to incorporate ionic cement binding sites into the non-ionic copolymer.
Abstract:
To provide cement additives which render high fluidity and the retention thereof, excellent shrinkage reducing effect and frost-thaw resistance to cement compositions such as mortar and concrete without entraining excessive air, and exhibit excellent solution stability.The present cement additives contain alkenyl group-containing polyalkylene compounds (SR), ester-based polycarboxylic acid copolymers (PC1) and ether-based polycarboxylic acid copolymers (PC2).
Abstract:
A polymer P for prolonging the flowability of water-reduced aqueous hydraulically setting compositions, and a method for prolonging the flowability of water-reduced aqueous hydraulically setting compositions.
Abstract:
The present invention relates to the use of polycationic compound in combination with a hydroxycarboxylic acid or salt thereof to enhance slump retention in cements and concretes having clay-bearing aggregates, wherein the clay otherwise absorbs or diminishes the dosage efficiency of polycarboxylate superplasticizers.
Abstract:
Methods of preparing design-optimized concrete compositions having target compressive strengths and slumps with a minimal amount of water are disclosed. In particular, the optimized concrete compositions are produced by analyzing pre-existing mix designs from a manufacture and determining the optimum amount of water required in the mix (i.e., optimized water to cement ratio) to obtain a target slump, yet allowing for the end-produced concrete composition to have a target compressive strength.
Abstract:
The present invention provides a dispersion-retaining agent for a hydraulic composition being excellent in both fluidity retainability and viscosity retainability and further a dispersion-retaining agent exhibiting fluidity retainability and viscosity retainability regardless of the type of hydraulic powder. The present invention relates to a dispersion-retaining agent for a hydraulic composition, containing a copolymer obtained by polymerizing specific monomer 1 represented by formula (1), with monomer 2 represented by formula (2), the corresponding alcohol compound of which satisfies specific physical properties, wherein, in the constituent monomers of the copolymer, the proportion of the monomer 1 is in a specific range, a specified monomers is used as at least a part of the monomer 2, and the proportion of monomers having an acid group or a neutralized group thereof is 5% by weight or less.