Low pH colloidal silica compositions for application to concrete

• US 9,272,951 B1
• Filed: 04/04/2015
• Issued: 03/01/2016
• Est. Priority Date: 02/05/2008
• Status: Active Grant

• Current Assignee: Adhesives Technology Corporation (Meridian Adhesives Group LLC)
• Original Assignee: ARRIS Technology, Inc. (CommScope Holding Company, Inc.)
• Inventors: Hills, Dal N., Barrus, Kent
• Primary Examiner(s): Marcantoni, Paul
• Application Number:
  US14/678,959
• Time in Patent Office: 332 Days
• US Class Current: 1/1
• CPC Class Codes: C04B 14/062 Microsilica, e.g. colloïdal silica preparing microsilica slurries or suspensions C04B18/148
• CPC Class Codes: C04B 14/303 Alumina
• CPC Class Codes: C04B 2103/40 Surface-active agents, dispersants
• CPC Class Codes: C04B 2103/606 Agents for neutralising Ca(OH)2 liberated during cement hardening
• CPC Class Codes: C04B 2111/00112 Mixtures characterised by specific pH values
• CPC Class Codes: C04B 22/06 Oxides, Hydroxides C04B22/0013 takes precedence
• 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 40/0295 Inhomogeneous curing or hardening, e.g. accelerated curing of surface regions of a concrete article; Influencing the setting or hardening process to generate physical or mechanical effects, e.g. to create cracks
• CPC Class Codes: C04B 41/009 characterised by the material treated
• CPC Class Codes: C04B 41/5089 Silica sols, alkyl, ammonium or alkali metal silicate cements
• CPC Class Codes: C04B 41/68 Silicic acid; Silicates
• CPC Class Codes: C09D 1/00 Coating compositions, e.g. paints, varnishes or lacquers, based on inorganic substances

Abstract

A composition for hardening concrete that has a pH of less than 10, and may have a pH of 8 or less. Thus, the hardening composition may be free of or substantially free of alkaline materials. The hardening composition is water-based and includes silica particles and stabilizer, which may be present on portions of the surfaces of the silica particles. The stabilizer may be aluminum-based (e.g., it may comprise alumina, etc.). In use, the hardening composition is applied to the surface of concrete, either alone, with curing compounds, or as part of a polishing process. Any residue that remains on the treated surface may simply be swept, blown, or sprayed away.

Claims

1. A composition for hardening and/or polishing concrete, consisting of:

colloidal silica;

a stabilizer for enabling the colloidal silica to remain in solution at a pH of less than 10;

surfactant; and

water,

the composition being formulated not to form a hard reside on a surface of the concrete.

2. The composition of claim 1, having a pH of 8 or less.

3. The composition of claim 1, having a neutral pH.

4. The composition of claim 1, having a pH of about 3.5 or less.

5. The composition of claim 1, wherein silica particles of the colloidal silica have diameters of about 3 nm to about 50 nm.

6. The composition of claim 5, wherein the silica particles have diameters of 12 nm.

7. The composition of claim 1, wherein silica particles of the colloidal silica comprise about 1.5% to about 6% of a weight of the composition.

8. The composition of claim 7, wherein the silica particles comprise about 4.5% of the weight of the composition.

9. A composition for application to a surface of concrete, comprising:

colloidal silica including silica particles with sizes that enable the silica particles to penetrate into the surface of the concrete to react with calcium hydroxide beneath the surface of the concrete; and

a stabilizer enabling silica particles of the colloidal silica to remain in solution at a pH below 10,

the composition formulated to harden the surface of the concrete without forming a hard residue on the surface.

10. The composition of claim 9, wherein silica particles of the colloidal silica have diameters of about 3 nm to about 50 nm.

11. The composition of claim 10, wherein the silica particles have diameters of about 12 nm.

12. The composition of claim 9, wherein the silica particles of the colloidal silica comprise about 1.5% to about 6% of a weight of the composition.

13. The composition of claim 9, wherein the colloidal silica comprises from about 5% to about 50% of a weight of the composition.

14. The composition of claim 9, wherein the stabilizer enables the silica particles to remain in solution at a pH of from about 3 to about 7.

15. The composition of claim 9, wherein the stabilizer enables the silica particles to remain in solution at a pH of about 3.5 or less.

20. The composition of claim 9, wherein the stabilizer enables the silica particles to remain in solution at a pH of from about 3 to about 7.

16. A composition for application to a surface of concrete, comprising:

colloidal silica including silica particles with sizes that enable the silica particles to penetrate into the surface of the concrete to react with calcium hydroxide beneath the surface of the concrete;

a stabilizer enabling the silica particles to remain in solution at a pH below 10;

surfactant; and

water,

the composition formulated to harden the surface of the concrete without forming a hard residue on the surface.

17. The composition of claim 16, wherein silica particles of the colloidal silica comprise about 1.5% to about 6% of a weight of the composition.

18. The composition of claim 16, wherein the colloidal silica comprises from about 5% to about 50% of a weight of the composition.

19. The composition of claim 16, wherein the stabilizer enables the silica particles to remain in solution at a pH of about 8 or less.