W. R. Grace Co.-conn.

Maria C Hicks

Neal Steven Berke

Ellis M Gartner

Ahmad Arfaei

Michael P Dallaire

Ding Feng Shen

James J Malone

Additive for cementitious compositions, comprising: at least one admixture, such a shrinkage reducing admixture, an air entraining admixture, a water reducing admixture, an inorganic salt, a corrosion inhibitor, an accelerator, a retarder, or mixture thereof; and a triblock polyoxyalkene copolymer surfactant having the formula R O&mdash;(A O) &mdash;(A O) &mdash;(A O) &mdash;R wherein R and R individually represent hydrogen, a C -C alkyl group, a C -C cycloalkyl group, or an aryl group; A represents a C alkyl group, A represents a branched or linear C alkyl group; &ldquo;x&rdquo; represents an integer of 42-133; and &ldquo;y&rdquo; represents an integer of 21 to 68.

Air entraining admixture compositions

Mixed anodic/cathodic corrosion inhibitors for use in hydraulic cement, comprising a) a first component consisting of an amount of alkali or alkaline earth metal nitrite sufficient to inhibit anodic corrosion; and b) a second component comprising an agent that acts to increases the anodic corrosion performance of the first component; wherein said first and second components are present in a weight ratio of from about 1:0.1 to 1:1. Optionally an EO/PO superplasticizer can be incorporated where the weight ratio of the first component, i.e., nitrite, to EO/PO superplasticizer is from about 1:0.005 to 1:0.25, with the surprising benefit of increased protection against cathodic corrosion without harming the level of anodic corrosion inhibition.

Nitrite-based corrosion inhibitors with improved anodic and cathodic

An admixture for cement compositions is provided which contributes both anodic and cathodic corrosion inhibition, and the cement compositions containing such additives. The cement additive is a combination of an anodic corrosion inhibitor such as calcium nitrite, and a cathodic corrosion inhibitor such as calcium stearate or other fatty acid. The mixed inhibitors in accordance with the invention provide as good or better corrosion inhibition than does calcium nitrite when used alone.

Corrosion inhibiting formulations with calcium nitrite

An additive combination for hydraulic cement compositions is provided which advantageously provides corrosion inhibition and set acceleration, in combination with a high level of fluidity and retention of fluidity over a desired period of time. The cement additive combination comprises an alkali or alkaline earth metal nitrite and a graft copolymer plasticizer comprising a polyether backbone and side chain polymers formed by polymerization of ethylenically unsaturated monomers. Fluid hydraulic cement compositions are further provided comprising these additive combinations.

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Newton, MA, United States of America

Maria C Hicks