EP1063321A2 - Améliorations dans la protection cathodique de structures en béton et de maçonnerie - Google Patents

Améliorations dans la protection cathodique de structures en béton et de maçonnerie Download PDF

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Publication number
EP1063321A2
EP1063321A2 EP00304730A EP00304730A EP1063321A2 EP 1063321 A2 EP1063321 A2 EP 1063321A2 EP 00304730 A EP00304730 A EP 00304730A EP 00304730 A EP00304730 A EP 00304730A EP 1063321 A2 EP1063321 A2 EP 1063321A2
Authority
EP
European Patent Office
Prior art keywords
current
cathodic protection
anodes
pin
circuit
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP00304730A
Other languages
German (de)
English (en)
Other versions
EP1063321A3 (fr
Inventor
Frits Gronvold
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Gronvold & Karnov As
Original Assignee
Gronvold & Karnov As
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Gronvold & Karnov As filed Critical Gronvold & Karnov As
Publication of EP1063321A2 publication Critical patent/EP1063321A2/fr
Publication of EP1063321A3 publication Critical patent/EP1063321A3/fr
Withdrawn legal-status Critical Current

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    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23F—NON-MECHANICAL REMOVAL OF METALLIC MATERIAL FROM SURFACE; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL; MULTI-STEP PROCESSES FOR SURFACE TREATMENT OF METALLIC MATERIAL INVOLVING AT LEAST ONE PROCESS PROVIDED FOR IN CLASS C23 AND AT LEAST ONE PROCESS COVERED BY SUBCLASS C21D OR C22F OR CLASS C25
    • C23F13/00—Inhibiting corrosion of metals by anodic or cathodic protection
    • C23F13/02—Inhibiting corrosion of metals by anodic or cathodic protection cathodic; Selection of conditions, parameters or procedures for cathodic protection, e.g. of electrical conditions
    • C23F13/04—Controlling or regulating desired parameters
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23F—NON-MECHANICAL REMOVAL OF METALLIC MATERIAL FROM SURFACE; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL; MULTI-STEP PROCESSES FOR SURFACE TREATMENT OF METALLIC MATERIAL INVOLVING AT LEAST ONE PROCESS PROVIDED FOR IN CLASS C23 AND AT LEAST ONE PROCESS COVERED BY SUBCLASS C21D OR C22F OR CLASS C25
    • C23F2201/00—Type of materials to be protected by cathodic protection
    • C23F2201/02—Concrete, e.g. reinforced

Definitions

  • This invention relates to cathodic protection for reinforced concrete or masonry structures and, in particular, cathodic protection of such structures using internal anodes.
  • the invention is particularly concerned with the prevention or reduction of corrosion of reinforcing elements in concrete and masonry structures using impressed current cathodic protection.
  • Cathodic protection for reinforced concrete structures is well-known and has for the last two decades been used to protect steel in concrete. These systems typically use an anode which feeds current, a cathode or metal structure to be protected and an electrolytic conductor between the anode and cathode.
  • the current is supplied by a power source feeding a continuous direct current (DC) and a reference electrode is utilised to indicate the required current.
  • DC direct current
  • the principle of cathodic protection is to transfer the natural surface potential of the structure to a more negative value so that the corrosion rate is slowed. If the potential of carbon steel is commonly taken to a more negative value than around -850mV Cu/CuSO 4 , the corrosion is stopped. For steel in concrete the depolarisation is also commonly used to denote reduction in corrosion rate.
  • the present invention aims to reduce the number of pin anodes required and yet still maintain the level and spread of the protection current. This gives a significant advantage both economically in material and installation cost and also causes significantly less disruption to the original structure.
  • a method for the cathodic protection of reinforced concrete or masonry structures in which a number of pin anodes are inserted and connected to a source of direct current, wherein a high frequency current interruption is imposed on the output of the DC circuit supplying current to the anode(s).
  • the high frequency current interruption is imposed in the range of 100 Hz to 10 MHz and a duty cycle typically of 1 to 99.9%.
  • the interruption can be caused by the imposition of a specially developed circuit on the output of a DC circuit.
  • This circuit is sufficiently specified to be able to switch the currents being delivered and will normally be between 1 mA and 5A, depending on the application.
  • the present invention also provides a circuit for performing the above-described method.
  • a current interruption circuit according to the invention comprises two unstable multivibrators M1 and M2 making a square pulse with adjustable frequency and pulse width. This pulse is used to control a semiconductor switch (power MOS) which switches the input from DC to interrupted current.
  • power MOS semiconductor switch
  • two pin anodes 11 and 12 were installed in a concrete deck slab 13 which was reinforced with a network of steel reinforcing rods 14 having a diameter of approximately 16mm.
  • a series of first reference electrodes MMO consisting of mixed metal oxide on a titanium substrate were installed in the reinforced concrete slab 13 at regular spaced intervals between the pin anodes 11 and 12 and a series of second reference electrodes G consisting of pure graphite were also installed in the reinforced concrete slab at regular spaced intervals between the pin electrodes 11 and 12.
  • the MMO electrodes were placed away from the reinforcement 14 while the G electrodes were placed close to the reinforcement.
  • the MMO electrodes measured approximately 6mm x 50mm while the G electrodes measured approximately 4mm x 20mm.
  • MMO+G MMO+G
  • the pin anodes 11 and 12 had an active length of about 90mm and were surrounded by an electrically conductive couplant (not shown). As indicated in Fig. 2, the pin anodes were located close to one another but were electrically isolated from each other.
  • the results of the trials are given in Figs. 3 and 4. These figures demonstrate that there is a difference in the attenuation between the interrupted and continuous currents.
  • the lines indicating the best fitting curves show the reproducibility of the experiments.
  • the interrupted current provides a substantial depolarisation effect at a distance, which is substantially greater than the continuous current.
  • 100 mV depolarisation which is BS 7361:Part 1:1991 Cathodic Protection advised minimum level
  • the interrupted current has a reach of 800mm with the continuous current reach of only 500mm.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Prevention Of Electric Corrosion (AREA)
EP00304730A 1999-06-17 2000-06-05 Améliorations dans la protection cathodique de structures en béton et de maçonnerie Withdrawn EP1063321A3 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB9914198 1999-06-17
GBGB9914198.8A GB9914198D0 (en) 1999-06-17 1999-06-17 Improvements in capthodic protection for concrete and masonry structures

Publications (2)

Publication Number Publication Date
EP1063321A2 true EP1063321A2 (fr) 2000-12-27
EP1063321A3 EP1063321A3 (fr) 2002-02-06

Family

ID=10855583

Family Applications (1)

Application Number Title Priority Date Filing Date
EP00304730A Withdrawn EP1063321A3 (fr) 1999-06-17 2000-06-05 Améliorations dans la protection cathodique de structures en béton et de maçonnerie

Country Status (2)

Country Link
EP (1) EP1063321A3 (fr)
GB (1) GB9914198D0 (fr)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1777322A1 (fr) * 2005-10-18 2007-04-25 Technische Universiteit Delft Appareil et méthode pour la protection cathodique d'une structure en béton armé
EP3916128A1 (fr) * 2020-05-27 2021-12-01 iCor Intelligent Corrosion Control GmbH Circuit de protection cathodique contre la corrosion et agencement de mesure lors de la protection cathodique contre la corrosion

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5324405A (en) * 1991-09-09 1994-06-28 Doniguian Thaddeus M Pulse cathodic protection system

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1777322A1 (fr) * 2005-10-18 2007-04-25 Technische Universiteit Delft Appareil et méthode pour la protection cathodique d'une structure en béton armé
EP3916128A1 (fr) * 2020-05-27 2021-12-01 iCor Intelligent Corrosion Control GmbH Circuit de protection cathodique contre la corrosion et agencement de mesure lors de la protection cathodique contre la corrosion

Also Published As

Publication number Publication date
GB9914198D0 (en) 1999-08-18
EP1063321A3 (fr) 2002-02-06

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