Abstract:
The present invention provides the early strengthening agent for hydraulic compositions containing a compound (a) obtained by reacting (A) one or more compounds selected from polyhydric alcohols having 3 to 20 hydroxy groups and alkylene oxide adducts thereof with (B) a sulfating agent, and the additive composition for hydraulic compositions containing the compound (a).
Abstract:
A method of formless underwater casting of cement is disclosed. The method involves the addition of silicate to water in which a structure bound with Portland cement or high-alumina cement is to be cast. The cementitious mixture as a slurry is then poured into the water to form a structure. The silicate and cementitious mixture can be placed in the water at the same time using concentric nozzle systems.
Abstract:
This rapid-hardening cement composition includes: a rapid-hardening admixture; and cement in an amount of 100 parts by mass to 2,000 parts by mass with respect to 100 parts by mass of the rapid-hardening admixture, wherein the rapid-hardening admixture is a composition that contains: calcium aluminate; inorganic sulfate in an amount of 50 parts by mass to 200 parts by mass with respect to 100 parts by mass of the calcium aluminate; and a setting modifier in an amount of 0.1 parts by mass to 10 parts by mass with respect to 100 parts by mass of the calcium aluminate, and an average particle diameter of the calcium aluminate is in a range of 8 μm to 100 μm, and an average particle diameter of the setting modifier is in a range of 5 μm or less.
Abstract:
The invention provides a cementitious composition comprising a cement component comprising (i) an accelerant, (ii) a calcium sulphate source and (iii) an ettringite forming cement; an aggregate; and optionally water; wherein the cement has a minimum unconfined compressive strength of 1500 psi when tested in accordance with ASTM C1140 and/or C1604 at 15 minutes after placement; methods for its use and concrete formed from it.
Abstract:
Cements or hydraulic binders may be prepared by adding an aqueous suspension comprising a ground mineral filler and at least one grinding aid agent to a cement or hydraulic binder. The resulting cement or hydraulic binder has very appreciably improved mechanical properties, particularly the property of “strength at young ages.” The grinding aid agent may be a natural or synthetic homopolymer and/or copolymer.
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 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 particularly, and also pertains to such hydraulic mixtures containing the calcium salt and copolymer.
Abstract:
A hydraulic binder includes a Portland clinker having a Blaine specific surface of 4000 to 5500 cm2/g, from 2.5 to 8% of sulphate expressed by mass of SO3 relative to the mass of clinker, from 1.5 to 10% of calcium nitrite and/or calcium nitrate expressed as anhydrous mass relative to the mass of clinker and from 15 to 50% of a mineral addition including calcium carbonate by mass relative to the total mass of binder.
Abstract:
Cements or hydraulic binders may be prepared by adding an aqueous suspension comprising a ground mineral filler and at least one grinding aid agent to a cement or hydraulic binder. The resulting cement or hydraulic binder has very appreciably improved mechanical properties, particularly the property of “strength at young ages.” The grinding aid agent may be a natural or synthetic homopolymer and/or copolymer.