Fly ash composition for use in concrete mix

• US 20020033119A1
• Filed: 06/25/2001
• Published: 03/21/2002
• Est. Priority Date: 01/28/2000
• Status: Active Grant

• Current Assignee: Mineral Resource Technologies, Inc. (Cemex, S.A.B. De C.V.)
• Original Assignee: Mineral Resource Technologies, Inc. (Cemex, S.A.B. De C.V.)
• Inventors: Styron, Robert William
• Granted Patent: US 6,482,258 B2
• Time in Patent Office: Days
• US Class Current: 106/705
• CPC Class Codes: C04B 14/106 Kaolin
• CPC Class Codes: C04B 18/08 Flue dust , i.e. fly ash
• CPC Class Codes: C04B 2103/0086 Chelating or complexing agents
• CPC Class Codes: C04B 2103/20 Retarders
• CPC Class Codes: C04B 22/0013 Boron compounds
• CPC Class Codes: C04B 22/10 containing carbon in the anion
• CPC Class Codes: C04B 24/06 containing hydroxy groups
• CPC Class Codes: C04B 24/123 Amino-carboxylic acids
• CPC Class Codes: C04B 28/04 Portland cements
• CPC Class Codes: C04B 40/0039 Premixtures of ingredients
• CPC Class Codes: C04B 40/0042 Powdery mixtures
• CPC Class Codes: Y02W 30/91 Use of waste materials as fillers for mortars or concrete
• CPC Class Codes: Y10S 106/01 Fly ash

Abstract

A fly ash composition is provided which includes a blend of Class C fly ash, potassium carbonate, and lithium carbonate, which, in combination, reduce alkali silica reactivity when the fly ash composition is used in concrete applications. The fly ash composition includes from about 65 to 99 wt % Class C fly ash, from about 0.1 wt. % to about 4 wt % potassium carbonate, and from about 0.1 wt. % to about 4 wt. % lithium carbonate.

Claims

1. A fly ash composition for use in a concrete mix comprising from about 65 wt. % to about 99% wt. % Class C fly ash;

from about 0.1 wt. % to about 4 wt. % of lithium carbonate, from about 0.1 to about 5 wt % potassium carbonate, and from about 0.1 to about 26% by weight of a retarding agent.

2. The fly ash composition of claim 1 further including 0.1 to 5 wt % of a chelating agent.

3. The fly ash composition of claim 1 wherein said retarding agent is selected from the group consisting of borax, boric acid, citric acid, metakaolins, and blends thereof.

4. The fly ash composition of claim 1 wherein said retarding agent comprises about 0.1 to 10 wt % metakaolin.

5. The fly ash composition of claim 1 wherein said retarding agent comprises from about 0.1 to 4 wt % Borax, from about 0.1 to 4 wt % boric acid, from about 0.1 to 8 wt % citric acid, and from about 0.1 to 10 wt % by weight metakaolin.

6. A concrete mix comprising stone, sand, water, and Portland cement, said mix including from about 25 to 40 wt % Class C fly ash, from about 0.1 wt. % to about 4 wt. % of lithium carbonate, from about 0.1 wt. % to about 5 wt. % potassium carbonate, and from about 0.1 to about 26% by weight of a retarding agent.

7. A concrete mix comprising stone, sand, water, and Portland cement, said mix including from about 25 to 65 wt % Class C fly ash, from about 0.1 wt. % to about 4 wt. % of lithium carbonate, from about 0.1 wt. % to about 5 wt. % potassium carbonate, and from about 0.1 to about 26% by weight of a retarding agent.