US4255241A
Expired / Lapsed
US
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Cathodic protection apparatus and method for steel reinforced concrete structures
Assignee: Corrpro Companies Inc
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Filing: 1979-05-10
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Granted: 1981-03-10
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Expires: 1999-05-10
Abstract
Abstract A cathodic protection system and method for steel reinforcement in concrete structures such as bridge decks, parking garage decks and highways utilizes platinized niobium or like metal wire anodes strategically positioned adjacent the concrete in a matrix of conductive carbonaceous material. The anode and matrix are preferably positioned in slots saw cut in the concrete surface avoiding the disposition of a conductive and wear resistant surface overlay which is not only expensive but which may exceed the design limitations of the structure. An impressed protective cathodic protection current is provided between the anodes and the steel of the structure. At places where the anode crosses in close proximity to reinforcing steel which may be exposed by the slot, or at places where cathodic protection current is not desired, a plastic sleeve may be placed over the anode. The anode may be connected directly to a current source or it may be spliced to an insulated copper lead wire and be brought down through the deck of the structure to be connected to the rectifier beneath the deck. Although more than one anode may be connected to any single rectifier circuit, it is preferred to have as many individual circuits as practicable to assist in analyzing the system performance with either permanently installed reference electrodes or portable reference electrodes.
Inventors
- 👤 David H. Kroon
- 👤 James B. Bushman
- 👤 Joseph W. Rog
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 18:37
CPC Classifications
C; C23; C23F; C23F13/00; C23F13/02; C23F2201/00; C23F2201/02
Claims Analysis
Total Claims: 36
Claim 1
Independent Claim
73 words
A cathodic protection system for pre-existing steel reinforced concrete structures comprising a slot formed in the top concrete surface of such structure, a thin elongate corrosion resistant, metal anode juxtaposed to the concrete of the structure in such slot and electrically spaced from the steel of the structure, said anode being surrounded by a matrix of conductive carbonaceous backfill material, and a power source impressing a current between the anode and the steel.
Claim 2
Dependent Claim
73 words
A cathodic protection system for pre-existing steel reinforced concrete structures comprising a slot formed in the top concrete surface of such structure, a thin elongate corrosion resistant, metal anode juxtaposed to the concrete of the structure in such slot and electrically spaced from the steel of the structure, said anode being surrounded by a matrix of conductive carbonaceous backfill material, and a power source impressing a current between the anode and the steel.
Claim 3
Dependent Claim
29 words
A system as set forth in claim 1 wherein said anode and matrix is positioned in such slot which is saw-cut in a top concrete surface of said structure.
Claim 4
Dependent Claim
30 words
A system as set forth in claim 2 wherein said slot is filled with conductive carbonaceous material to form said matrix and said anode is in the approximate center thereof.
Claim 5
Dependent Claim
24 words
A system as set forth in claim 2 wherein said anode is insulated in areas where reinforcing steel may be exposed by said slot.
Claim 6
Dependent Claim
24 words
A system as set forth in claim 2 wherein said matrix is interrupted in areas where reinforcing steel may be exposed by said slot.
Claim 7
Dependent Claim
28 words
A system as set forth in claim 2 wherein said anode is insulated and said matrix interrupted in areas where reinforcing steel may be exposed by said slot.
Claim 8
Dependent Claim
16 words
A system as set forth in claim 2 wherein said matrix is covered with plastic tape.
Claim 9
Dependent Claim
19 words
A system as set forth in claim 2 wherein said matrix is enclosed top and bottom by plastic tape.
Claim 10
Dependent Claim
33 words
A system as set forth in claim 2 wherein said matrix is covered by a wear resistant sealant to bring the contents of the slot substantially flush with the surface of the structure.
Claim 11
Dependent Claim
21 words
A system as set forth in claim 2 wherein said slot is formed by adding to the surface of said structure.
Claim 12
Dependent Claim
47 words
A system as set forth in claim 2 wherein said structure is a reinforced concrete slab, and a hole drilled in the end of said slot to extend through said slab, said anode extending through said hole so that the electrical connection thereto is beneath said slab.
Claim 13
Dependent Claim
30 words
A system as set forth in claim 11 including a junction box on the underside of said slab, and a copper lead connected to said anode in said junction box.
Claim 14
Dependent Claim
19 words
A system as set forth in claim 11 wherein said hole is filled with a plastic or elastomeric sealant.
Claim 15
Dependent Claim
21 words
A system as set forth in claim 1 wherein said anode is a thin wire of a platinum coated reactive metal.
Claim 16
Dependent Claim
22 words
A system as set forth in claim 14 wherein said reactive metal is selected from the group of columbium, titanium or tantalum.
Claim 17
Dependent Claim
14 words
A system as set forth in claim 15 wherein said thin wire is copper-cored.
Claim 18
Dependent Claim
36 words
A system as set forth in claim 1 wherein the principal ingredient of said carbonaceous material is selected from the group consisting of graphite, coke breeze, metallurgical coke, calcined fluid petroleum coke, or calcined petroleum coke.
Claim 19
Independent Claim
56 words
A method of cathodically protecting a pre-existing metal reinforced concrete structure comprising the steps of strategically positioning slots near the top surface of the structure, positioning elongated corrosion resistant, metal wire or rod anodes adjacent the concrete in such slots in a matrix of carbonaceous backfill material, and impressing a protective current flow from the anodes.
Claim 20
Independent Claim
56 words
A method of cathodically protecting a pre-existing metal reinforced concrete structure comprising the steps of strategically positioning slots near the top surface of the structure, positioning elongated corrosion resistant, metal wire or rod anodes adjacent the concrete in such slots in a matrix of carbonaceous backfill material, and impressing a protective current flow from the anodes.
Claim 21
Dependent Claim
32 words
A method as set forth in claim 18 including the step of saw-culting a slot in a top surface of the concrete and positioning said anode and the matrix in such slot.
Claim 22
Dependent Claim
20 words
A method as set forth in claim 19 including sealing the slot substantially flush with the surface of the concrete.
Claim 23
Dependent Claim
23 words
A method as set forth in claim 19 wherein the slot is formed by parallel saw cuts with the area therebetween broken out.
Claim 24
Dependent Claim
22 words
A method as set forth in claim 19 wherein the slot is formed by adding concrete to the surface of the structure.
Claim 25
Dependent Claim
28 words
A method as set forth in claim 19 including the step of drilling a hole in the end of the slot, and extending the anode through the hole.
Claim 26
Dependent Claim
28 words
A method as set forth in claim 23 including the step of electrically connecting the anode to a lead at the end of the hole opposite the slot.
Claim 27
Dependent Claim
15 words
A method as set forth in claim 23 including the step of sealing the hole.
Claim 28
Dependent Claim
37 words
A method as set forth in claim 19 including the step of carefully inspecting the slot after forming for exposed reinforcing metal, and in the area of any exposed metal insulating the anode and interrupting the matrix.
Claim 29
Dependent Claim
31 words
A method as set forth in claim 26 wherein the step of insulating the anode includes placing plastic tape over the exposed metal, and surrounding the anode with a dielectric sealant.
Claim 30
Dependent Claim
27 words
A method as set forth in claim 27 including the step of enclosing the anode in a plastic tube and surrounding the tube with such dielectric sealant.
Claim 31
Dependent Claim
24 words
A method as set forth in claim 19 wherein the matrix includes plastic tape confining the top and bottom thereof with a sealant thereover.
Claim 32
Dependent Claim
19 words
A method as set forth in claim 18 wherein the anode is a wire of platinum coated reactive metal.
Claim 33
Dependent Claim
23 words
A method as set forth in claim 30 wherein the reactive metal is selected from the group consisting of columbium, titanium or tantalum.
Claim 34
Dependent Claim
19 words
A method as set forth in claim 31 wherein the wire is straightened before being placed in the matrix.
Claim 35
Dependent Claim
13 words
A method as set forth in claim 31 wherein said wire is copper-cored.
Claim 36
Dependent Claim
34 words
A method as set forth in claim 18 wherein the matrix includes a conductive ingredient selected from the group consisting of coke breeze, graphite, metallurgical coke, calcined fluid petroleum coke, or calcined petroleum coke.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1984-03-09 | 1984-09-08 | 1985-03-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-03-09 | 1988-09-08 | 1989-03-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-03-09 | 1992-09-08 | 1993-03-10 | $7700.00 | Window Closed / Lapsed |