HIGH EARLY STRENGTH POZZOLAN CEMENT BLENDS

• US 20100089293A1
• Filed: 10/08/2009
• Published: 04/15/2010
• Est. Priority Date: 10/10/2008
• Status: Active Grant

• Current Assignee: Roman Cement, LLC
• Original Assignee: Roman Cement, LLC
• Inventors: Guynn, John M., Hansen, Andrew S.
• Granted Patent: US 7,799,128 B2
• Time in Patent Office: Days
• US Class Current: 106/709
• CPC Class Codes: C04B 14/14 Minerals of vulcanic origin granite C04B14/048
• CPC Class Codes: C04B 18/08 Flue dust , i.e. fly ash
• CPC Class Codes: C04B 20/0076 characterised by the grain distribution
• CPC Class Codes: C04B 20/008 Micro- or nanosized fillers, e.g. micronised fillers with particle size smaller than that of the hydraulic binder colloidal silica C04B14/062 ; silica fume C04B18/146
• CPC Class Codes: C04B 2103/0088 Compounds chosen for their latent hydraulic characteristics, e.g. pozzuolanes
• CPC Class Codes: C04B 2103/10 Accelerators; Activators
• CPC Class Codes: C04B 2103/20 Retarders
• CPC Class Codes: C04B 2103/302 Water reducers
• CPC Class Codes: C04B 2103/44 Thickening, gelling or viscosity increasing agents
• CPC Class Codes: C04B 22/064 of the alkaline-earth metals
• CPC Class Codes: C04B 28/02 containing hydraulic cements other than calcium sulfates
• CPC Class Codes: C04B 28/18 containing mixtures of the silica-lime type
• CPC Class Codes: C04B 7/02 Portland cement
• 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 high early strength pozzolan cement includes larger sized pozzolan particles and smaller sized hydraulic cement particles which contain tricalcium silicate (e.g., Portland cement). Particles larger than 10 μm are predominantly (50%, 65%, 75%, 85% or 95%) pozzolan particles, and particles smaller than 10 μm are predominantly (50%, 65%, 75%, 85% or 95%) hydraulic cement particles. Excess calcium from the hydraulic cement forms calcium hydroxide available for reaction with the pozzolan particles, optionally in combination with supplemental lime. At least 30%, 40%, 45%, 55%, 65% or 75% of the pozzolan cement (combined pozzolan and hydraulic cement particles) consists of pozzolan, and less than 70%, 60%, 55%, 45%, 35% or 25% consists of hydraulic cement.

Claims

1. A pozzolan cement composition comprising:

a distribution of differently sized pozzolan particles capable of reacting with calcium hydroxide in the presence of water in order to form solid hydration products having cementitious properties, the pozzolan particles having a D₁₅ greater than about 5 μ

m; and

a distribution of differently sized hydraulic cement particles at least partially comprised of tricalcium silicate and/or dicalcium silicate that provide excess calcium hydroxide when mixed with water and that is available for reaction with at least a portion of the pozzolan particles, the hydraulic cement particles having a D₈₅ less than about 20 μ

m.

2. A pozzolan cement composition as in claim 1, the pozzolan particles having a D₁₀ greater than about 5 μ

m and the hydraulic cement particles having a D₉₀ less than about 20 μ

m.

3. A pozzolan cement composition as in claim 1, the pozzolan particles having a D₅ greater than about 5 μ

m and the hydraulic cement particles having a D₉₅ less than about 20 μ

m.

4. A pozzolan cement composition as in claim 1, the pozzolan particles having a D₁₅ greater than about 10 μ

m and the hydraulic cement particles having a D₈₅ less than about 15 μ

m

5. A pozzolan cement composition as in claim 1, the pozzolan particles having a D₁₀ greater than about 10 μ

m and the hydraulic cement particles having a D₉₀ less than about 15 μ

m.

6. A pozzolan cement composition as in claim 1, the pozzolan particles having a D₁₅ greater than about 15 μ

m and the hydraulic cement particles having a D₈₅ less than about 10 μ

m

8. A pozzolan cement composition as in claim 1, the pozzolan particles comprising at least 30% by volume of combined pozzolan and hydraulic cement particles and the hydraulic cement particles comprising up to 70% by volume of the combined pozzolan and hydraulic cement particles.

9. A pozzolan cement composition as in claim 1, further comprising at least one of a fine aggregate, a coarse aggregate, lime, lye, water reducing admixture, accelerant, retardant, hydration stabilizer, rheology-modifying agent, or water.

10. A pozzolan cement composition as in claim 1, the pozzolan cement composition having a Blaine fineness in a range of about 280 m²/kg to about 600 m²/kg.

11. A pozzolan cement composition as in claim 1, the pozzolan cement composition having a Blaine fineness in a range of 300 m²/kg to about 500 m²/kg.

12. A pozzolan cement composition as in claim 1, the hydraulic cement particles having a Blaine fineness greater than about 500 m²/kg and the pozzolan particles having a Blaine fineness less than about 325 m²/kg.

14. A pozzolan cement composition as in claim 1, the hydraulic cement particles having a Blaine fineness greater than about 800 m²/kg and the pozzolan particles having a Blaine fineness less than about 275 m²/kg.

7. (canceled)

13. (canceled)

15. A method of manufacturing a pozzolan cement composition, comprising:

providing an initial stream of hydraulic cement particles;

providing an initial stream of pozzolan particles;

grinding and/or classifying the hydraulic cement particles in order to yield a modified stream of hydraulic cement particles of increased fineness compared to the initial stream of hydraulic cement particles and which has a D₉₀ of less than about 20 μ

m;

removing at least a portion of the pozzolan particles less than about 20 μ

m and/or grinding at least a portion of the pozzolan particles to yield a modified stream of pozzolan particles having a D₉₀ less than about 120 μ

m and a D₁₀ greater than about 10 μ

m; and

blending the modified streams of hydraulic cement and pozzolan particles to yield the pozzolan cement composition.

16. A method as in claim 15, further comprising removing at least a portion of the pozzolan particles greater than about 60 μ

m to yield the modified stream of pozzolan particles having a D₉₀ of less than about 80 μ

m.

17. A method as in claim 15, further comprising adding at least one of gypsum, fine aggregate, coarse aggregate, lime, lye, water reducing admixture, accelerant, retardant, hydration stabilizer, rheology-modifying agent, or water to the pozzolan cement composition.

18. A method as in claim 15, further comprising blending the pozzolan cement composition with one or more aggregates and water to yield a concrete composition.

19. A method as in claim 18, wherein the hydraulic cement particles and the pozzolan particles are blended together during manufacturing of the concrete composition.

20. A pozzolan cement composition comprising:

pozzolan particles capable of reacting with calcium hydroxide in the presence of water in order to form solid hydration products having cementitious properties; and

hydraulic cement particles at least partially comprised of tricalcium silicate and/or dicalcium silicate that provide excess calcium hydroxide when mixed with water and that is available for reaction with at least a portion of the pozzolan particles,

wherein at least about 90% by volume of combined pozzolan and hydraulic cement particles greater than about 20 μ

m are composed of pozzolan particles,

wherein at least about 90% by volume of combined pozzolan and hydraulic cement particles less than about 5 μ

m are composed of hydraulic cement particles.

21. A pozzolan cement composition as in claim 20, wherein at least about 90% by volume of the combined pozzolan and hydraulic cement particles greater than about 15 μ

m are composed of the pozzolan particles and at least about 90% by volume of the combined pozzolan and hydraulic cement particles less than about 7.5 μ

m are composed of the hydraulic cement particles.

23. A pozzolan cement composition as in claim 20, wherein the pozzolan comprises at least one member selected from the group consisting of fly ash, trass, and volcanic ash.

22. (canceled)