Pozzolanic compositions containing fly ash and remediation agents for use in cementitious materials
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.
1. A pozzolanic composition for use in concrete, said composition comprising a non-spec fly ash and/or 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 %, wherein the combination of said natural pozzolan with said non-spec fly ash and/or said Class C fly ash results in said pozzolanic composition meeting a specification for pozzolanic mixtures, pozzolan admixtures, or supplementary cementitious materials in concrete under ASTM and/or AASHTO, wherein (a) when said composition comprises a non-spec fly ash, said specification is a Class C fly ash specification or a Class F fly ash specification pertaining to pozzolanic admixtures in concrete; and (b) when said composition comprises a Class C fly ash, said specification is a Class F fly ash specification.
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 a 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 natural pozzolan is a volcanic ash with pozzolanic properties.
6. 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.
7. The pozzolanic composition of claim 1 , wherein said natural pozzolan is a material defined as a natural pozzolan pursuant to an ASTM and/or AASHTO specification pertaining to natural pozzolans for use in concrete.
8. The pozzolanic composition of claim 1 , wherein said natural pozzolan is calcined.
9. The pozzolanic composition of claim 1 , said composition further comprising an additive to adjust viscosity of said composition.
10. The pozzolanic composition of claim 1 , said composition further comprising an additive to adjust water demand of said composition in concrete.
11. A cementitious mixture comprising a pozzolanic composition for use in concrete, said composition comprising a non-spec fly ash and/or 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, wherein the combination of said natural pozzolan with said non-spec fly ash and/or said Class C fly ash results in said pozzolanic composition meeting a specification for pozzolanic mixtures, pozzolan admixtures, or supplementary cementitious materials in concrete under ASTM and/or AASHTO, wherein (a) when said composition comprises a non-spec fly ash, said specification Class C fly ash specification or a Class F fly ash specification pertaining to pozzolanic admixtures in concrete; and (b) when said composition comprises a Class C fly ash, said specification is a Class F fly ash specification.
12. The cementitious mixture of claim 11 , 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.
13. The cementitious mixture of claim 12 , wherein a 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.
14. The cementitious mixture of claim 11 , wherein said natural pozzolan is a material defined as a natural pozzolan pursuant to ASTM C618 and/or AASHTO M295.
15. The cementitious mixture of claim 11 , wherein said natural pozzolan is a material defined as a natural pozzolan pursuant to an ASTM and/or AASHTO specification pertaining to natural pozzolans for use in concrete.
16. A concrete product or structure comprising aggregate and said cementitious mixture of claim 11 , or a reaction product thereof.
17. A method of producing a pozzolanic composition for use in concrete, said method comprising:
providing a source of fly ash that is a non-spec fly ash and/or a Class C fly ash;
providing a natural pozzolan; and
combining said non-spec fly ash and/or said Class C fly ash with said natural pozzolan, to produce a pozzolanic composition meeting a specification for pozzolanic mixtures, pozzolan admixtures, or supplementary cementitious materials in concrete under ASTM and/or AASHTO, wherein (a) when said composition comprises a non-spec fly ash, said specification is a Class C fly ash specification or a Class F fly ash specification, pertaining to pozzolanic mixtures, pozzolan admixtures, or supplementary cementitious materials in concrete, wherein said non-spec fly ash and/or said Class C fly ash is upgraded by the presence of said natural pozzolan to enhance its pozzolanic properties prior to addition of said pozzolanic composition to said concrete.
18. The method of claim 17 , wherein said natural pozzolan is present in a concentration of about 1 wt % to about 99 wt % in said pozzolanic composition.
19. The method of claim 18 , wherein said natural pozzolan is present in a concentration of about 10 wt % to about 90 wt % in said pozzolanic composition.
20. The method of claim 17 , wherein said natural pozzolan is a material defined as a natural pozzolan pursuant to ASTM C618 and/or AASHTO M295.
21. The method of claim 17 , wherein said natural pozzolan is a material defined as a natural pozzolan pursuant to an ASTM and/or AASHTO specification pertaining to natural pozzolans for use in concrete.