United States Gypsum Company

Marianela Perez-Pena

Ashish Dubey

Srinivas Veeramasuneni

Yanfei Peng

Disclosed is a foamed cementitious composition which limits or eliminates aggregate, especially porous lightweight aggregate and uses a lower than usual water to cementitious composition weight ratio. The stable cementitious foam mixtures may be employed to make cement boards and other cement products. The foamed cementitious composition was made with additions of PVOH foaming stabilizer and surfactant foaming agents to make foam water or by entrain air into cementitious slurry mixtures. The cementitious mixtures have a limited amount or preferably no perlite and no lightweight aggregate. The resulting foamed mixture had foam bubbles with size in the range of 50 to 200 &#x3bc;m. After setting the foamed cementitious composition the resulting set board has air cells with size in the range of 50 to 200 &#x3bc;m.

Lightweight foamed cement, cement board, and methods for making same

A method of making a rapid setting composition for cement boards is disclosed. Compositions including a hydraulic cement preferably portland cement, an alkali metal citrate such as tripotassium citrate, and a phosphate such as sodium trimetaphosphate, with optional gypsum, and no alkanolamine accelerant, and no fly ash based cement. An interaction between the alkali metal citrate and the phosphate increases the effectiveness of accelerating reactions of the portland cement without need for an alkanolamine accelerant, even in the presence of gypsum. This allows unexpected quick setting and increased early-age compressive strength without shrinkage in the cement board compositions.

Fast setting portland cement compositions with alkali metal citrates and phosphates with high early-age compressive strength and reduced shrinkage

A method of making a rapid setting lightweight homogeneous foamed fly ash based cementitious aggregate composition with improved compressive strength for products such as panels is disclosed. The method mixes fly ash, alkali metal salt of citric acid, foaming agent for entraining air, optional foam stabilizing agent, a calcium sulfate such as stucco or gypsum, and water. Compositions are also disclosed which include mixtures of fly ash, particularly Class C fly ash alone or in mixtures with Class F fly ash, alkali metal salts of citric acid, foaming agents, a calcium sulfate such as calcium sulfate dihydrate or hemihydrate and an optional portland cement.

Method for in-situ manufacture of a lightweight fly ash based aggregate

A method of making a rapid setting lightweight cementitious composition with improved compressive strength for products such as boards is disclosed. The method mixes fly ash, alkali metal salt of citric acid and lightweight aggregate with water. Compositions which include fly ash, alkali metal salts of citric acid and lightweight aggregate are also disclosed.

Fly ash based lightweight cementitious composition with high compressive strength and fast set

A method of making a lightweight cementitious binder composition with improved compressive strength for products such as cementitious panels is disclosed. The method mixes fly ash, alkali metal salt of citric acid, alkali metal silicate, foaming agent for entraining air, water and in the preferred embodiment a foam stabilizing agent. Compositions which include fly ash selected from the group consisting of class C fly ash, class F fly ash and mixtures thereof, alkali metal salts of citric acid, alkali metal silicates, foaming agents, and preferably a foam stabilizer, such as polyvinyl alcohol, and do not require use of set retarders. Compositions containing class F fly ash can optionally contain Type III Portland cement.

Lightweight foamed fly ash based binders and method

A method of making a rapid setting composition for cement boards is disclosed. Compositions including portland cement, fly ash, gypsum, alkanolamine and phosphate are disclosed. A synergistic interaction between the alkanolamine and phosphate increases the effectiveness of accelerating reactions thus allowing for quick setting and increased early-age compressive strength compositions.

Very fast setting cementitious composition with high early-age compressive strength

Extremely fast setting of cementitious compositions for producing cement-based products such as cement boards is made possible by adding an alkanolamine to a hydraulic cement such as portland cement, and forming a slurry with water under conditions that provide an initial slurry temperature of at least 90&#xb0; F. Use of alkanolamine under conditions disclosed herein allows an extremely rapid setting of the cementitious composition. Additional reactive materials may be included such as high alumina cement, calcium sulfate and a pozzolanic material such as fly ash. The extremely fast rapid set permits rapid production of cementitious products.

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Grayslake, IL, United States of America

Marianela Perez-Pena