White pozzolan composition and blended cements containing same

• US 6,776,838 B2
• Filed: 03/01/2002
• Issued: 08/17/2004
• Est. Priority Date: 03/02/2001
• Status: Active Grant

• Current Assignee: Joseph Keating
• Original Assignee: Albacem, LLC
• Inventors: Nelson, Robert D., Graves, Philip L., Cornelius, Bruce J., Hemmings, Raymond T.
• Primary Examiner(s): Green, Anthony J.
• Application Number:
  US10/087,064
• Publication Number:
  US 20030047119A1
• Time in Patent Office: 900 Days
• Field of Search: 106/711, 106/712, 106/819, 106/716, 428/402, 501/35
• US Class Current: 106/716
• CPC Class Codes: C03C 3/087 containing calcium oxide, e.g. common sheet or container glass
• CPC Class Codes: C03C 3/091 containing aluminium
• CPC Class Codes: C04B 14/22 Glass ; Devitrified glass
• CPC Class Codes: C04B 20/026 Comminuting, e.g. by grinding or breaking; Defibrillating fibres other than asbestos
• CPC Class Codes: C04B 2111/802 White cement
• CPC Class Codes: C04B 28/02 containing hydraulic cements other than calcium sulfates
• 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 7/13 Mixtures thereof with inorganic cementitious materials, e.g. Portland cements
• CPC Class Codes: Y10T 428/2982 Particulate matter [e.g., sphere, flake, etc.]

Abstract

A white pozzolan derived from by-products of manufacturing vitreous low alkali, low iron glass fibers, and to the method for producing the white pozzolan. The invention relates as well to cement compositions based on the white pozzolan, such as white and pigmented blended pozzolanic cements of high durability for use in applications such as white or colored architectural concrete, building materials, and manufactured cementitious products. The white pozzolan also functions as a high performance pozzolan with grey cement.

Claims

1. A blended pozzolanic cement produced by blending with portland cement, from 5 to 40% by weight of the total composition of a fine white pozzolan comprising a finely ground vitreous calcium aumino-silicate (CaO—

Al₂O₃—

SiO₂) powder derived from previously discarded glass fibers having low alkali and low iron content and low levels of discolorants;

said powder having an alkali content by weight of not more than 2% as (Na₂O+K₂O), an iron content by weight of not more than 0.8% as Fe₂O₃, and being substantially white in color with a reflectance value of at least 80 as measured by a Technibrite TB-1C colorimeter according to the ISO 2467, 2471 method;

at least 95% by weight of the powder comprising particles of less than 45 microns E.S.D. and said particles having a blocky, relatively equi-dimensional particle shape wherein the average aspect ratio of the particles is less than 2;

1, and with substantially no residual high aspect ratio fibers.

2. A blended cement in accordance with claim 1, which is substantially white.

3. A blended pozzolanic cement in accordance with claim 1, further comprising one or more functional cement additives selected from the group consisting of accelerators, retarders, water-reducers/plasticizers, corrosion inhibitors, and pigments.

4. A colored pozzolanic cement comprising the white cement of claim 2 together with an admixed coloring pigment.

5. A white pozzolan for blending with portland cement for use in white and colored concrete applications, comprising a finely ground vitreous calcium aumino-silicate (CaO—

Al₂O₃—

SiO₂) powder derived from previously discarded glass fibers having low alkali and low iron content, and low levels of discolorants;

said powder having an alkali content by weight of not more than 2% as (Na₂O+K₂O), an iron content by weight of not more than 0.8% as Fe₂O₃, and being substantially white in color with a reflectance value of at least 80 as measured by a Technibrite TB-1C colorimeter according to the ISO 2467, 2471 method;

at least 95% by weight of the powder comprising particles of less than 45 microns E.S.D. and said particles having a blocky, relatively equi-dimensional particle shape wherein the average aspect ratio of the particles is less than 2;

1, and with substantially no residual high aspect ratio fibers.

6. A composition in accordance with claim 5, wherein the said pozzolan has a P.S.D. such that at least 95% by weight of the particles are of less than 25 microns E.S.D.

7. A composition in accordance with claim 5, wherein the said pozzolan has a P.S.D. such that at least 95% by weight of the particles are of less than 10 microns E.S.D.

8. A composition in accordance with claim 5, wherein the said pozzolan has a P.S.D. such that at least 95% by weight of the particles are of less than 5 microns E.S.D.

9. A composition in accordance with claim 5, wherein the said pozzolan has a P.S.D. such that at least 95% by weight of the particles are of less than 3 microns E.S.D.

10. A white pozzolanic cement produced by intergrinding of a vitreous low alkali, low iron pozzolan in accordance with claim 5 with white portland cement clinker and white gypsum.

11. A white pozzolanic cement in accordance with claim 10, wherein said white clinker is selected from one or more members of the group consisting of Type I, Type II, Type III, Type IV, and Type V ASTM C-150 cements.

12. A raw feed for white cement clinker production comprising a finely ground vitreous low alkali, and low iron content pozzolan in accordance with claim 5 derived from fine grinding of glass fibers.