Abstract: A superior cement dispersant and a concrete composition containing the cement dispersant, the cement dispersant being a water-soluble amphoteric copolymer which contains an alkylene oxide adduct of a polyamide polyamine having an unsaturated group and at least two types of polyalkylene glycol ester. When the cement dispersant is compounded with a concrete composition, the dispersion performance thereof increases with time, and the concrete viscosity is effectively decreased. The cement dispersant composition contains a water-soluble amphoteric copolymer or the neutralized salt thereof as an essential component, which is obtained by copolymerizing an alkylene oxide adduct of a polyamide polyamine having an unsaturated group, (meta)acrylic acid or an alkali metal, ammonium, or alkanolamine salt thereof, an ester of an alkylene glycol and methacrylic acid, and an ester of an alkylene glycol and acrylic acid. In addition, the concrete composition containing the above cement dispersant is also disclosed.

Abstract: There is provided a powdered polycarboxylic acid-based cement dispersant containing a polyamide-polyamine in a skeleton of a polymer thereof and a dispersant composition containing the dispersant, the dispersant having improved water reducing ability, slump-flow retention, and strength-developing properties of concrete, enabling effective prevention of blocking, being highly soluble in a slurry, and being homogeneously mixed with an inorganic powder. The powdered polycarboxylic acid-based cement dispersant comprises a powdered cement dispersant obtained by dry-powdering a solution or dispersion of a copolymer containing a polyamide-polyamine in a skeleton of a polymer thereof, wherein the powder has a sphere form, an average particle diameter of 30 to 300 ?m, and a particle size distribution in which the mass of particles having a particle diameter of 50 to 350 ?m accounts for 70% or more of the total mass of the powder.

Abstract: [Object] To provide a cement dispersant and a concrete composition containing the cement dispersant, the cement dispersant having a superior effect of decreasing a high concrete paste viscosity while a water reducing effect, a slump flow retention, and rapid strength development are being satisfied in a region having a low water/binder ratio. [Solving Means] The cement dispersant for ultrahigh performance concrete is provided which is a water-soluble amphoteric copolymer obtained by copolymerizing (A) an alkylene oxide adduct of a polyamide polyamine having an unsaturated group, (B) (meta)acrylic acid or a salt thereof, (C) an ester of a short-chain alkylene glycol and (meth)acrylic acid, and (D) an ester of a long-chain alkylene glycol and (meth)acrylic acid at ratios A:B:C:D of 5 to 25:5 to 30:5 to 40:20 to 80 (percent by weight), in which the total is 100% percent by weight. In addition, the concrete composition containing the above cement dispersant is provided.

Abstract: A cement dispersant (especially a dispersant for concretes with ultrahigh performance) comprising as a main component a water-soluble amphoteric copolymer obtained by copolymerizing (A) a polyamide-polyamine of an alkylene oxide adduct thereof with (B) (meth)acrylic acid or an alkali metal, ammonium, or alkanolamine salt thereof and (C) a polyalkylene glycol ester of (meth)acrylic acid in an A/B/C ratio of (10-40)/(10-40)/(50-80) (wt. %); and a concrete composition (especially an ultral high-performance concrete) containing the dispersant. The dispersant satisfies all of a water-reducing effect, slump flow retention, strength development, etc.