High early-strength-enhancing admixture for precast hydraulic cement and compositions containing same

US5840114A · kind A · utility

Assignee

• W.R. Grace & Co.-Conn. · US

Inventors

• Ara A. Jeknavorian · Chelmsford, US
• Ahmad Arfaei · Chelmsford, US
• Neal S. Berke · Portage, US
• David C. Darwin · Columbia, US
• Ellis Gartner · Silver Spring, US
• Leslie A. Jardine · Salem, US
• James Franklin Lambert · Sharon, US
• Lawrence R. Roberts · Acton, US

Key dates

• Filing date: May 17, 1996
• Grant date: Nov 24, 1998
• Expiry date: May 17, 2016

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C04B2201/05
• WIPO field: Materials, metallurgy
• WIPO sector: Chemistry

Abstract

A high early strength admixture for precast hydraulic cement comprises a calcium salt and a copolymer having a carbon-containing backbone to which are attached cement-anchoring members, such as carboxyl groups, and to which are also attached oxyalkylene pendant groups by linkages selected from the group consisting of amide and imide members. The copolymers used are preferably formed by reacting an acrylic polymer with ammonia or an alkoxylated amine. The calcium salt, preferably calcium nitrite, and the copolymer can be added simultaneously as one admixture, or separately. The invention relates also to methods for enhancing high early strength in concrete, cement, masonry, and mortar mixtures generally, and to precast concrete particarly, and also pertains to such hydraulic mixtures containing the calcium salt and copolymer.