Pozzolanic compositions containing fly ash and remediation agents for use in cementitious materials

• US 9,611,174 B2
• Filed: 06/30/2016
• Issued: 04/04/2017
• Est. Priority Date: 06/25/2014
• Status: Active Grant

• Current Assignee: Cr Minerals Company Llc
• Original Assignee: Cr Minerals Company Llc
• Inventors: Thomas, Joseph Earl, Carter, Richard Douglas, Whidden, Jeffrey Alexander
• Primary Examiner(s): Green, Anthony J
• Application Number:
  US15/199,821
• Publication Number:
  US 20160311723A1
• Time in Patent Office: 278 Days
• CPC Class Codes: C04B 14/04 Silica-rich materials; Silicates
• CPC Class Codes: C04B 14/08 Diatomaceous earth
• CPC Class Codes: C04B 14/106 Kaolin
• CPC Class Codes: C04B 14/12 Expanded clay
• CPC Class Codes: C04B 14/14 Minerals of vulcanic origin granite C04B14/048
• CPC Class Codes: C04B 14/16 porous, e.g. pumice
• CPC Class Codes: C04B 14/18 Perlite
• CPC Class Codes: C04B 14/22 Glass ; Devitrified glass
• CPC Class Codes: C04B 18/023 Fired or melted materials
• CPC Class Codes: C04B 18/08 Flue dust , i.e. fly ash
• CPC Class Codes: C04B 18/088 in high volume fly ash compositions
• CPC Class Codes: C04B 18/141 Slags
• CPC Class Codes: C04B 18/146 Silica fume
• CPC Class Codes: C04B 2103/0088 Compounds chosen for their latent hydraulic characteristics, e.g. pozzuolanes
• CPC Class Codes: C04B 2111/2015 Sulfate resistance
• CPC Class Codes: C04B 2111/2023 Resistance against alkali-aggregate reaction
• CPC Class Codes: C04B 2111/21 Efflorescence resistance
• CPC Class Codes: C04B 2111/26 Corrosion of reinforcement resistance
• CPC Class Codes: C04B 28/02 containing hydraulic cements other than calcium sulfates
• CPC Class Codes: C04B 28/021 Ash cements, e.g. fly ash cements fly ash as filler C04B18/08; Cements based on incineration residues, e.g. alkali-activated slags from waste incineration alkali-activated combustion residues as such C04B7/243; mixtures of the lime-pozzuolane type C04B28/18; Kiln dust cements
• CPC Class Codes: C04B 28/18 : containing mixtures of the silica-lime type
• CPC Class Codes: C04B 40/0039 : Premixtures of ingredients
• CPC Class Codes: C04B 7/02 : Portland cement
• CPC Class Codes: C04B 7/12 : Natural pozzuolanas; Natural pozzuolana cements; Artificial pozzuolanas or artificial pozzuolana cements other than those obtained from waste or combustion residues, e.g. burned clay; Treating inorganic materials to improve their pozzuolanic characteristics cements containing slag C04B7/14
• CPC Class Codes: C04B 7/26 : from raw materials containing flue dust , i.e. fly ash C04B7/243 takes precedence
• CPC Class Codes: Y02P 40/10 : Production of cement, e.g. improving or optimising the production methods; Cement grinding
• CPC Class Codes: Y02W 30/91 : Use of waste materials as fillers for mortars or concrete

Abstract

It has been unexpectedly discovered that the addition of a natural or other pozzolan to non-spec fly ash significantly improves the properties of the non-spec fly ash to the extent it can be certified under ASTM C618 and AASHTO 295, as either a Class F or Class C fly ash. The natural pozzolan may be a volcanic ejecta, such as pumice or perlite. Other pozzolans may also be used for this beneficiation process. Many pozzolans are experimentally tested and may be used to beneficiate non-spec fly ash into certifiable Class F fly ash. Additionally, this disclosure provides a method of converting a Class C fly ash to a more valuable Class F fly ash. This discovery will extend diminishing Class F fly ash supplies and turn non-spec fly ash waste streams into valuable, certified fly ash pozzolan which will protect and enhance concrete, mortars and grouts.

Claims

1. A pozzolanic composition for use in concrete, said composition comprising a Class C fly ash combined with a natural pozzolan, wherein said natural pozzolan is present in a concentration of about 1 wt % to about 99 wt %, and wherein the combination of said natural pozzolan with said Class C fly ash results in said pozzolanic composition meeting specifications under ASTM C618 and/or AASHTO M295 as a Class F pozzolan for pozzolanic admixtures in concrete.

2. The pozzolanic composition of claim 1, wherein said natural pozzolan is present in a concentration of about 10 wt % to about 90 wt %.

3. The pozzolanic composition of claim 1, wherein a weight ratio of said natural pozzolan to said fly ash is from about 0.01 to about 100 parts natural pozzolan divided by parts fly ash.

4. The pozzolanic composition of claim 3, wherein said weight ratio of said natural pozzolan to said fly ash is from about 0.1 to about 10 parts natural pozzolan divided by parts fly ash.

5. The pozzolanic composition of claim 1, wherein said composition consists of said Class C fly ash combined with said natural pozzolan.

6. The pozzolanic composition of claim 1, wherein said natural pozzolan is a volcanic ash with pozzolanic properties.

7. The pozzolanic composition of claim 1, wherein said natural pozzolan is calcined.

8. The pozzolanic composition of claim 1, wherein said natural pozzolan is a material defined as a natural pozzolan pursuant to ASTM C618 and/or AASHTO M295.

9. A cementitious mixture comprising a pozzolanic composition for use in concrete, said composition comprising a Class C fly ash combined with a natural pozzolan, wherein said natural pozzolan is present in a concentration of about 1 wt % to about 99 wt % of said pozzolanic composition, and wherein the combination of said natural pozzolan with said Class C fly ash results in said pozzolanic composition meeting specifications under ASTM C618 and/or AASHTO M295 as a Class F pozzolan for pozzolanic admixtures in concrete.

10. The cementitious mixture of claim 9, wherein a weight ratio of said natural pozzolan to said fly ash is from about 0.01 to about 100 parts natural pozzolan divided by parts fly ash.

11. The cementitious mixture of claim 10, wherein said weight ratio of said natural pozzolan to said fly ash is from about 0.1 to about 10 parts natural pozzolan divided by parts fly ash.

12. The cementitious mixture of claim 9, wherein said natural pozzolan is a material defined as a natural pozzolan pursuant to ASTM C618 and/or AASHTO M295.

13. A concrete product or structure comprising aggregate and said cementitious mixture of claim 9, or a reaction product thereof.

14. A method of producing a pozzolanic composition for use in concrete, said method comprising:

providing a source of fly ash that is a Class C fly ash;

providing a natural pozzolan; and

combining said Class C fly ash with said natural pozzolan, to produce a pozzolanic composition meeting specifications under ASTM C618 and/or AASHTO M295 as a Class F pozzolan for pozzolanic admixtures in concrete, wherein said Class C fly ash is upgraded to said Class F pozzolan by the presence of said natural pozzolan to enhance its pozzolanic properties prior to addition of said pozzolanic composition as an admixture to said concrete.

15. The method of claim 14, wherein said natural pozzolan is present in a concentration of about 1 wt % to about 99 wt % in said pozzolanic composition.

16. The method of claim 15, wherein said natural pozzolan is present in a concentration of about 10 wt % to about 90 wt % in said pozzolanic composition.

17. The method of claim 14, wherein said natural pozzolan is a material defined as a natural pozzolan pursuant to ASTM C618 and/or AASHTO M295.