Processes for improving the bond between hydrating cement-based materials and existing cement-based substrates

• US 5,505,987 A
• Filed: 01/20/1995
• Issued: 04/09/1996
• Est. Priority Date: 10/10/1989
• Status: Expired due to Fees

• Current Assignee: E. Khashoggi Industries, LLC
• Original Assignee: Anthony J. Kelzenberg, Hamlin M. Jennings, Simon K. Hodson
• Inventors: Hodson, Simon K., Jennings, Hamlin M., Kelzenberg, Anthony J.
• Primary Examiner(s): DUDASH, DIANA L
• Application Number:
  US08/376,890
• Time in Patent Office: 445 Days
• Field of Search: 427/136, 427/140, 427/299, 427/301, 427/355, 427/403, 427/309, 427/427
• US Class Current: 427/136
• CPC Class Codes: B01F 2025/91 Direction of flow or arrangement of feed and discharge openings
• CPC Class Codes: B01F 27/50 Pipe mixers, i.e. mixers wherein the materials to be mixed flow continuously through pipes, e.g. column mixers
• CPC Class Codes: B01F 27/80 with stirrers rotating about a substantially vertical axis
• CPC Class Codes: B01F 27/86 co-operating with deflectors or baffles fixed to the receptacle
• CPC Class Codes: B28B 1/00 Producing shaped prefabricated articles from the material using presses B28B3/00; shaping on moving conveyors B28B5/00; producing tubular articles B28B21/00 ; producing articles with embedded elements B28B23/00
• CPC Class Codes: B28B 11/24 for curing, setting or hardening processes for influencing or modifying the setting or hardening ability of mortars, concrete or artificial stone compositions, in general C04B40/00
• CPC Class Codes: B28B 11/245 Curing concrete articles B28B11/242 takes precedence
• CPC Class Codes: B28B 23/0087 Lightweight aggregates for making lightweight articles
• CPC Class Codes: B28B 7/342 which are at least partially destroyed, e.g. broken, molten, before demoulding; Moulding surfaces or spaces shaped by, or in, the ground, or sand or soil, whether bound or not; Cores consisting at least mainly of sand or soil, whether bound or not
• CPC Class Codes: B28C 5/388 Methods
• CPC Class Codes: C04B 2111/72 Repairing or restoring existing buildings or building materials
• CPC Class Codes: C04B 22/002 Water
• CPC Class Codes: C04B 28/04 Portland cements
• CPC Class Codes: C04B 40/00 Processes, in general, for influencing or modifying the properties of mortars, concrete or artificial stone compositions, e.g. their setting or hardening ability active ingredients C04B22/00 - C04B24/00; hardening of a well-defined composition C04B26/00 - C04B28/00; making porous, cellular or lightening C04B38/00; mechanical aspects B28, e.g. conditioning the materials prior to shaping B28B17/02
• CPC Class Codes: C04B 40/0035 Processes characterised by the absence of a mechanical mixing step, e.g. "no-mix" processes
• CPC Class Codes: C04B 40/0231 Carbon dioxide hardening
• CPC Class Codes: C04B 40/0616 preformed, e.g. bandages
• CPC Class Codes: C04B 41/5076 with masses bonded by inorganic cements sulfur compositions C04B41/5097
• CPC Class Codes: C04B 7/527 obtaining cements characterised by fineness, e.g. by multi-modal particle size distribution
• CPC Class Codes: E01C 7/147 Repairing concrete pavings, e.g. joining cracked road sections by dowels, applying a new concrete covering applying thin surface layers with other binder E01C7/35; repairing pavings in general E01C11/005; roughening by means of tools E01C11/24
• CPC Class Codes: E01C 7/351 : with exclusively hydraulical binders; Aggregate, fillers or other additives for application on or in the surface of toppings with exclusively hydraulic binders
• CPC Class Codes: Y02P 40/18 : Carbon capture and storage [CCS]

Abstract

Cement compositions and processes for improving the bond between new hydrating cement-based materials and the surface of "old" cement-based substrates are disclosed. A mechanically and chemically integral bond is created between the surfaces of the cement-based materials by moistening the old cement-based surface, exposing the moist surface to carbon or carbonate sources (such as with carbon dioxide) and then applying a new hydrating cement-based material thereon. The treatment of the surface of the cement-based substrate as described above creates an aqueous phase chemistry thereon which is compatible to the aqueous phase chemistry of the hydrating cement-based materials applied thereafter. The compatibility of the aqueous phase chemistries results in a mechanically and chemically integral bond formed between the surface of the old cement-based surface and the hydrating cement-based materials. The bond interface may be characterized by low calcium hydroxide concentrations, the presence of amorphous, noncrystalline material, a low water/cement ratio, greater than 90% of all voids being less than 0.15 mm. in diameter, and a low total air content of the interface. The present invention is particularly applicable to the repairing, resurfacing and topping of existing concrete highways, roads and surfaces.

Claims

1. A method for bonding a hydrating cement-based material onto a surface of an existing cement-based substrate in order to form a mechanically integral bond interface therebetween, the method comprising the steps of:

(a) moistening the surface of an existing cement-based substrate with water;

(b) contacting the moistened surface of the cement-based substrate with carbon dioxide having a concentration greater than carbon dioxide found in atmospheric conditions;

(c) mixing together hydraulic cement, water, and an aggregate material in a manner which yields a hydrating cement-based material in which the hydraulic cement, water, and aggregate material have been substantially homogeneously mixed;

(d) applying the hydrating cement-based material onto the surface of the cement-based substrate; and

(e) allowing the hydrating cement-based material to harden in order to form a mechanically integral bond interface between the hydrating cement-based material and the cement-based substrate.

2. A method for bonding a hydrating cement-based material onto a surface of an existing cement-based substrate as defined in claim 1, wherein the bond between the hydrating cement-based material and the surface of the cement-based substrate is obtained without an organic bonding agent.

3. A method for bonding a hydrating cement-based material onto a surface of an existing cement-based substrate as defined in claim 1, further comprising the step of applying at least one additional hydrating cement-based material over the hydrating cement-based material applied onto the surface of the cement-based substrate.

4. A method for bonding a hydrating cement-based material onto a surface of an existing cement-based substrate as defined in claim 3, wherein the hydrating cement-based material applied onto the surface of the cement-based substrate comprises a mixture of cement paste and silica fume.

5. A method for bonding a hydrating cement-based material onto a surface of an existing cement-based substrate as defined in claim 3, wherein the at least one additional hydrating cement-based material has been substantially homogeneously mixed.

6. A method for bonding a hydrating cement-based material onto a surface of an existing cement-based substrate as defined in claim 1, wherein the aggregate material comprises microsilica.

7. A method for bonding a hydrating cement-based material onto a surface of an existing cement-based substrate as defined in claim 1, wherein step (d) includes working the hydrating cement-based material into pores within the surface of the cement-based substrate after applying the hydrating cement-based material onto the cement-based substrate.

8. A method for bonding a hydrating cement-based material onto a surface of an existing cement-based substrate as defined in claim 1, wherein step (d) includes hand scrubbing the hydrating cement-based material into the surface of the cement-based substrate.

9. A method for bonding a hydrating cement-based material onto a surface an existing cement-based substrate as defined in claim 1, further comprising the step of cleaning the surface of the existing cement-based substrate prior to step (a) in order to remove noncementitious materials from pores within the surface of the existing cement-based substrate.

10. A method for bonding a hydrating cement-based material onto a surface of an existing cement-based substrate as defined in claim 1, wherein the aqueous phase chemistry of the surface of the existing cement-based substrate is in a supersaturated state with respect to calcium ions after steps (a) and (b).

11. A method for bonding a hydrating cement-based material onto a surface of an existing cement-based substrate as defined in claim 1, wherein the existing cement-based substrate comprises concrete which has begun to set.

12. A method for bonding a hydrating cement-based material onto a surface of an existing cement-based substrate as defined in claim 1, wherein the hydraulic cement in the hydrating cement-based material comprises silica aluminate cement.

13. A method for bonding a hydrating cement-based material onto a surface of an existing cement-based substrate as defined in claim 1, wherein the hydraulic cement in the hydrating cement-based material comprises a portland cement.

14. A method for bonding a hydrating cement-based material onto a surface of an existing cement-based substrate as defined in claim 1, wherein the hydraulic cement in the hydrating cement-based material comprises a mixture of chemically different hydraulic cements.

15. A method for bonding a hydrating cement-based material onto a surface of an existing cement-based substrate as defined in claim 1, wherein the hydraulic cement in the hydrating cement-based material comprises calcium aluminate cement.

16. A method for bonding a hydrating cement-based material onto a surface of an existing cement-based substrate as defined in claim 1, wherein the hydraulic cement in the hydrating cement-based material comprises dicalcium silicate cement.

17. A method for bonding a hydrating cement-based material onto a surface of an existing cement-based substrate as defined in claim 1, wherein the hydraulic cement in the hydrating cement-based material comprises tricalcium silicate cement.

18. A method for bonding a hydrating cement-based material onto a surface of an existing cement-based substrate as defined in claim 1, wherein the hydraulic cement in the hydrating cement-based material comprises phosphate cement.

19. A method for bonding a hydrating cement-based material onto a surface of an existing cement-based substrate as defined in claim 1, step (c) includes mixing carbon dioxide into the hydrating cement-based material.

20. A method for bonding a hydrating cement-based material onto a surface of an existing cement-based substrate as defined in claim 1, wherein the hydrating cement-based material has a ratio of water to hydraulic cement in a range from about 0.01 to about 5.

21. A method for bonding a hydrating cement-based material onto a surface of an existing cement-based substrate as defined in claim 1, wherein the aggregate material comprises a plurality of differently sized aggregate particles.

22. A method for bonding a hydrating cement-based material onto a surface of an existing cement-based substrate as defined in claim 1, wherein the aggregate material includes a plurality of fibers.

23. A method for bonding a hydrating cement-based material onto a surface of an existing cement-based substrate as defined in claim 22, wherein the fibers comprise glass fibers.

24. A method for bonding a hydrating cement-based material onto a surface of an existing cement-based substrate as defined in claim 22, wherein the fibers comprise alumina fibers.

25. A method for bonding a hydrating cement-based material onto a surface of an existing cement-based substrate as defined in claim 22, wherein the fibers comprise silica fibers.

26. A method for bonding a hydrating cement-based material onto a surface of an existing cement-based substrate as defined in claim 22, wherein the fibers comprise metallic fibers.

27. A method for bonding a hydrating cement-based material onto a surface of an existing cement-based substrate as defined in claim 22, wherein the fibers comprise organic fibers.

28. A method for bonding a hydrating cement-based material onto a surface of an existing cement-based substrate as defined in claim 1, wherein the surface of the cement-based substrate is exposed to the carbon dioxide for a time period sufficient to supersaturate the aqueous phase chemistry of the surface of the cement-based substrate with carbonate ions.

29. A method for bonding a hydrating cement-based material onto a surface of an existing cement-based substrate as defined in claim 1, wherein the mechanically integral bond interface that is formed between the hydrating cement-based material and the cement-based substrate is stronger than the tensile strength of the cement-based substrate.

30. A method for bonding a hydrating cement-based material onto a surface of an existing cement-based substrate in order to form a mechanically integral bond interface therebetween, the method comprising the steps of:

(a) moistening the surface of the existing cement-based substrate with an aqueous carbonate solution;

(b) mixing together hydraulic cement, water, and an aggregate material in a manner which yields a hydrating cement-based material in which the hydraulic cement, water, and aggregate material have been substantially homogeneously mixed;

(c) applying the hydrating cement-based material onto the cement-based substrate; and

(d) allowing the hydrating cement-based material to harden in order to form a mechanically integral bond interface between the hydrating cement-based material and the cement-based substrate.

31. A method for bonding a hydrating cement-based material onto a surface of an existing cement-based substrate as defined in claim 30, herein the aqueous carbonate solution includes a carbonated water solution.

32. A method for bonding a hydrating cement-based material onto a surface of an existing cement-based substrate as defined in claim 30, wherein the aqueous carbonate solution includes a carbonate or bicarbonate salt.

33. A method for bonding a hydrating cement-based material onto a surface of an existing cement-based substrate as defined in claim 30, wherein the bond interface between the hydrating cement-based material and the cement-based substrate is obtained without an organic bonding agent.

34. A method for bonding a hydrating cement-based material onto a surface of an existing cement-based substrate as defined in claim 30, further comprising the step of applying at least one additional hydrating cement-based material over of the hydrating cement-based material applied onto the surface of the cement-based substrate.

35. A method for bonding a hydrating cement-based material onto a surface of an existing cement-based substrate as defined in claim 34, wherein the hydrating cement-based material applied onto the surface of the cement-based substrate comprises a mixture of cement paste and silica fume.

36. A method for bonding a hydrating cement-based material onto a surface of an existing cement-based substrate as defined in claim 35, wherein the at least one additional hydrating cement-based material comprises concrete that has been substantially homogeneously mixed.

37. A method for bonding a hydrating cement-based material onto a surface of an existing cement-based substrate as defined in claim 30, wherein the aggregate material comprises microsilica.

38. A method for bonding a hydrating cement-based material onto a surface of an existing cement-based substrate as defined in claim 30, wherein step (c) includes working the hydrating cement-based material into the surface of the cement-based substrate.

39. A method for bonding a hydrating cement-based material onto a surface of an existing cement-based substrate as defined in claim 30, wherein step (c) includes hand scrubbing the hydrating cement-based material into the surface of the cement-based substrate.

40. A method for bonding a hydrating cement-based material onto a surface an existing cement-based substrate as defined in claim 30, further comprising the step of cleaning the surface of the existing cement-based substrate prior to step (a) in order to remove noncementitious materials from pores within the surface of the existing cement-based substrate.

41. A method for bonding a hydrating cement-based material onto a surface of an existing cement-based substrate as defined in claim 30, wherein the aqueous phase chemistry of the surface of the cement-based substrate is in a supersaturated state with respect to calcium ions after step (a).

42. A method for bonding a hydrating cement-based material onto a surface of an existing cement-based substrate as defined in claim 30, wherein the existing cement-based substrate comprises concrete which has begun to set.

43. A method for bonding a hydrating cement-based material onto a surface of an existing cement-based substrate as defined in claim 30, wherein the hydraulic cement in the hydrating cement-based material comprises silica aluminate cement.

44. A method for bonding a hydrating cement-based material onto a surface of an existing cement-based substrate as defined in claim 30, wherein the hydraulic cement in the hydrating cement-based material comprises a portland cement.

45. A method for bonding a hydrating cement-based material onto a surface of an existing cement-based substrate as defined in claim 30, wherein the hydraulic cement in the hydrating cement-based material comprises a mixture of chemically different hydraulic cements.

46. A method for bonding a hydrating cement-based material onto a surface of an existing cement-based substrate as defined in claim 30, wherein the hydraulic cement in the hydrating cement-based material comprises calcium aluminate cement.

47. A method for bonding a hydrating cement-based material onto a surface of an existing cement-based substrate as defined in claim 30, wherein the hydraulic cement in the hydrating cement-based material comprises dicalcium silicate cement.

48. A method for bonding a hydrating cement-based material onto a surface of an existing cement-based substrate as defined in claim 30, wherein the hydraulic cement in the hydrating cement-based material comprises tricalcium silicate cement.

49. A method for bonding a hydrating cement-based material onto a surface of an existing cement-based substrate as defined in claim 30, wherein the hydraulic cement in the hydrating cement-based material comprises phosphate cement.

50. A method for bonding a hydrating cement-based material onto a surface of an existing cement-based substrate as defined in claim 30, wherein step (b) includes mixing carbon dioxide into the hydrating cement-based material.

51. A method for bonding a hydrating cement-based material onto a surface of an existing cement-based substrate as defined in claim 30, wherein the hydrating cement-based material has a ratio of water to hydraulic cement in a range from about 0.01 to about 5.

52. A method for bonding a hydrating cement-based material onto a surface of an existing cement-based substrate as defined in claim 30, wherein the aggregate material comprises a plurality of differently sized and graded aggregates.

53. A method for bonding a hydrating cement-based material onto a surface of an existing cement-based substrate as defined in claim 30, wherein the aggregate includes a plurality of fibers.

54. A method for bonding a hydrating cement-based material onto a surface of an existing cement-based substrate as defined in claim 53, wherein the fibers include glass fibers.

55. A method for bonding a hydrating cement-based material onto a surface of an existing cement-based substrate as defined in claim 53, wherein the fibers include alumina fibers.

56. A method for bonding a hydrating cement-based material onto a surface of an existing cement-based substrate as defined in claim 53, wherein the fibers include silica fibers.

57. A method for bonding a hydrating cement-based material onto a surface of an existing cement-based substrate as defined in claim 53, wherein the fibers include metallic fibers.

58. A method for bonding a hydrating cement-based material onto a surface of an existing cement-based substrate as defined in claim 53, wherein the fibers include organic fibers.

59. A method for bonding a hydrating cement-based material onto a surface of an existing cement-based substrate as defined in claim 30, wherein the surface of the cement-based substrate is exposed to the aqueous carbonate solution for a time period sufficient to supersaturate the aqueous phase chemistry of the surface of the cement-based substrate with carbonate ions.

60. A method for bonding a hydrating cement-based material onto a surface of an existing cement-based substrate as defined in claim 30, wherein the mechanically integral bond interface that is formed between the hydrating cement-based material and the cement-based substrate is stronger than the tensile strength of the cement-based substrate.