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

摘要

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.

主权项

1. A loose aggregate composition consisting of loose aggregate particles separated from a mixture of ingredients:
the mixture consisting of: water, cementitious reactive powder consisting of fly ash and a calcium sulfate selected from the group consisting of calcium sulfate hemihydrate, calcium sulfate dihydrate, and mixtures thereof, and optional silica fume, an alkali metal salt of citric acid selected from the group consisting of sodium citrate, potassium citrate and mixtures thereof, a foaming agent, optionally at least one or more members selected from the group consisting of secondary aggregate other than said loose aggregate, superplasticizer, set accelerating agents other than said alkali metal salt of citric acid, set retarding agents, shrinkage control agents, thickening agents, coloring agents, and internal curing agents, and aggregate particles consisting of the fly ash and calcium sulfate in the mixture and crystalline hydration products of the fly ash and calcium sulfate which are interspersed within and between the aggregate particles to bind the aggregate particles.