WO1992013116A1 - Materiau antirouille et procede d'application - Google Patents

Materiau antirouille et procede d'application Download PDF

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Publication number
WO1992013116A1
WO1992013116A1 PCT/US1992/000624 US9200624W WO9213116A1 WO 1992013116 A1 WO1992013116 A1 WO 1992013116A1 US 9200624 W US9200624 W US 9200624W WO 9213116 A1 WO9213116 A1 WO 9213116A1
Authority
WO
WIPO (PCT)
Prior art keywords
zinc
concrete
structure according
steel
sheet
Prior art date
Application number
PCT/US1992/000624
Other languages
English (en)
Inventor
Dodd S. Carr
Rodney G. Powers
Robert M. Langley
Ivan R. Lasa
Original Assignee
International Lead Zinc Research Organization, Inc.
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 International Lead Zinc Research Organization, Inc. filed Critical International Lead Zinc Research Organization, Inc.
Publication of WO1992013116A1 publication Critical patent/WO1992013116A1/fr

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Classifications

    • 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
    • C23F13/06—Constructional parts, or assemblies of cathodic-protection apparatus

Definitions

  • the cracked concrete may be chipped away from the corroding steel rebars; the exposed areas may be thoroughly sandblasted to remove any rust and loose concrete; and
  • a fusion bonded epoxy film is used to encapsulate the deformed (ridged) steel rebar with a corrosion resistant coating.
  • the epoxy film is damaged during shipment; during bending; during cutting to length; and during installation with bare or coated steel tie wires.
  • saltwater corrosion proceeds rapidly through the many defects in the epoxy film on the steel rebar. This causes the concrete to crack and spall in the same way as with bare steel rebars.
  • the chemical composition of the zinc is environmentally acceptable; the perforations provide a means of maintaining a moist condition in the concrete, thereby offering a necessary conductive path between the sacrificial zinc anode and the embedded steel rebars in the concrete; no expensive rectifier and electrical wiring system is needed; the protective current to the steel rebar is self controlled by the natural corrosion potential of zinc in saltwater; problems of gassing and acid formation are avoided, and the protective system of perforated zinc is easily, rapidly, and economically installed.
  • perforated zinc sheets illustrates the present concept of cathodic protection of steel rebars in concrete, other forms of zinc sheets may be employed with equal efficacy.
  • expanded zinc mesh prepared by slitting zinc sheets at longitudinal intervals and then stretching the sheets transversely, may be used effectively.
  • any other metallic elements above mild steel in the electromotive series in seawater could be employed; for example, cadmium, aluminum, and magnesium.
  • these alternative materials would not be preferred because of their toxicity (cadmium) or rapid rate of consumption (aluminum and magnesium) .
  • Figure 1 is a side view of concrete pier structure with a cathodic protection system according to the present invention.
  • Figure 2 is a cross-sectional view of Figure 1 taken at plane A-A.
  • Figure 3 is a graph depicting E-log-I test criteria.
  • Figure 4 is a graph depicting depolarizing test results.
  • Figure 4a is a graph also depicting depolarizing test results.
  • Figure 4b is a graph also depicting depolarizing test results.
  • a concrete pier 11 has imbedded therein steel rebars 12.
  • a perforated zinc sheet 13 is wrapped around the pier in the intertidal zone 30 (i.e. the zone encompassing mean low tide and mean high tide water levels) and is held firmly in place by mats 14.
  • the mats as shown in Fig. 2, have vertical grooves 15 which allow seawater to irrigate the zinc sheet.
  • the mats are held in place by straps 16, preferably of stainless steel.
  • the mats serve to space the straps away from the zinc sheet at the corners of the piers thus relieving a potential stress and excessive corrosion point.
  • An electrical connection is maintained between the zinc sheet and the rebar, e.g., by a wire 17, and a bore hole 18 in the concrete may be made for this purpose.
  • Example 1 Strips of perforated zinc sheets, nine inches wide by 0.049 inch thick by four feet long, were fabricated into two open cage structures large enough to wrap around the four sides of two steel reinforced concrete highway bridge piers, in saltwater (B.B. McCormick Bridge, U.S. Highway 90, Jacksonville, Florida) .
  • the composition of the perforated zinc sheet was as follows:
  • Zinc Balance The perforations were approximately 0.75 inch in diameter and the solid area between holes was about 0.05 inch.
  • One end of each perforated zinc sheet was bent tightly around the solid zinc strip and crimped. Then, soft solder (rosin core) was used to join the splice areas of the perforated sheets to the solid zinc supporting strip.
  • each cage structure was placed around a concrete pier (piers A and E) ; tapped firmly around each corner of the concrete piers; and electrically connected to the steel rebar through a bore hole in the concrete above the high tide mark (a hole was drilled and tapped into the exposed rebar through the bore hole) .
  • the midline of the perforated zinc sheet cage was positioned at the mean high tide level of the concrete pier.
  • each retainer was 15.0 inches wide by 1.75 inches thick with a tapered profile thinner toward the corners of the pier (to assure uniform pressure distribution across each perforated zinc sheet) ; a one-half inch radius of curvature was used longitudinally along each side of each four-foot long plastic retainer (to avoid sharp bends in the stainless steel binder straps) ; and the flat, contact surface of the plastic retainer was ribbed with parallel longitudinal grooves 3/16 inch wide by 3/16 inch deep. The grooves provide tidal irrigation of saltwater to the perforations in the zinc sheets to flush away any acidic films that may have formed, and increase the compressive forces exerted on the zinc-concrete interface by reducing the compression-transmitting contact areas.
  • Mitigation of corrosion utilizing the herein described system was achieved by allowing direct ionic current flow from the zinc sheets onto the surface of the reinforcing steel and electronic current flow through the direct connection between the zinc and the steel.
  • the direct current was supplied by the zinc sheets, which maintain a higher electromotive potential in relation to the rebar, without requiring an external power source.
  • the E-log-I criteria for cathodic protection states that by graphical analysis of the curve produced by the plotting of the polarized voltage potentials against the log of the current applied, the minimum required current for cathodic protection can be determined.
  • the current supplied by the anode (perforated zinc sheets) was applied to the structure in small increments, producing a polarized potential shift at the cathode (steel) .
  • the potentials do not shift significantly.
  • the potentials shift to a point where a direct relationship exists between the potential and the logarithm of the current, producing a linear segment in the polarization curve. From this linear relationship (Tafel Slope) , the minimum amount of current required for cathodic protection (Icp) and its corresponding cathodic protection potential (Ecp) as well as the corrosion current (Icorr) can be graphically determined.
  • Example 2 To further corroborate the cathodic polarization level achieved, four identical test probes were embedded in the concrete at the same depth of the reinforcing steel on each pile. Polarization was verified by interrupting the direct current flow while monitoring the open circuit potential decay for a period of four hours. The results of this test are shown in the following Tables 1(a) and 1(b):
  • Example 3 Complementary to the herein described corrosion control system, additional sacrificial zinc can be applied to the structure surface at elevations above the perforated zinc panels if corrosion levels at those elevations so require.
  • This can be achieved by arc or flame sprayed zinc metalizing on the concrete surface.
  • This method applies the zinc by means of equipment designed to feed two zinc wires through a handheld gun provided with the capability of maintaining an electric arc or a continuous flame which melts the zinc wires.
  • a trigger type switch on the gun activates the preset air nozzle which sprays the molten zinc onto the concrete surface.
  • the sprayed zinc provides the protection current for the steel at this elevation while the perforated zinc protects the tidal areas elevation.
  • This sprayed zinc coating is depicted in Fig. 1 at the area 19.
  • the sprayed zinc surface may be electrically connected to the rebars by a wire or the like (not shown) .
  • Example 4 When corrosion protection requirements of steel rebars in concrete bridge piers extend to elevations below the perforated zinc sheet system, additional sacrificial zinc bulk anodes 21 (Fig. 1) can be incorporated below the intertidal zone and electrically connected to the zinc sheets by connection means 22. By placing the bulk anodes in permanent direct contact with the tidal waters, additional protection current can flow through the water onto the concrete and then onto the embedded reinforcing steel surface. This procedure will extend the service life of the perforated zinc sheets by supplying the necessary current to protect the steel below the tidal area which otherwise would use current from the perforated zinc during high tides.
  • Example 5 installation of the perforated zinc sheets around steel reinforced concrete piers in saltwater environments is greatly facilitated by means of a novel plastic-wood attachment device.
  • a novel plastic-wood attachment device is manufactured by Riverhead Milling Inc., Philadelphia, PA, and employs a composite of recycled plastics and wood. It is designed to apply uniform pressure of the perforated zinc sheet against the faces of the concrete pier; it floats in saltwater and can be easily retrieved if dropped; it provides a unique means of irrigating the zinc-concrete interface; and it can be easily and rapidly installed and held in place with corrosion resistant stainless steel straps.
  • the corrosion prevention device will mitigate corrosion of reinforcing steel embedded in concrete at the intertidal zone.
  • the perforated zinc sheets may be fabricated to conform to different shapes and dimensions of various structures.
  • the fabrication being relatively simple, the material derived from recycled products, and the elimination of extensive electrical work and maintenance costs, it is believed that the hereby presented corrosion prevention device exhibits a superior cost effective system in relation to other conventional devices for steel protection in marine environments.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Prevention Of Electric Corrosion (AREA)

Abstract

Des tôles perforées (13) en zinc laminé, maintenues contre des piliers (11) d'autoroutes en béton à armure en acier immergés dans des zones intertidales d'eau de mer (30) offrent une protection cathodique sacrificielle à l'acier enrobé (12). Des extrusions composites (14) uniques en plastique/bois recyclé, cannelées, compriment les tôles en zinc perforées fermement contre les quatre faces des piliers en béton au moyen de bandes (16) de serrage en acier inoxydable résistantes.
PCT/US1992/000624 1991-01-25 1992-01-24 Materiau antirouille et procede d'application WO1992013116A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US64579691A 1991-01-25 1991-01-25
US645,796 1991-01-25

Publications (1)

Publication Number Publication Date
WO1992013116A1 true WO1992013116A1 (fr) 1992-08-06

Family

ID=24590516

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/US1992/000624 WO1992013116A1 (fr) 1991-01-25 1992-01-24 Materiau antirouille et procede d'application

Country Status (3)

Country Link
AU (1) AU1342392A (fr)
CA (1) CA2101251A1 (fr)
WO (1) WO1992013116A1 (fr)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2730751A1 (fr) * 1995-02-21 1996-08-23 Gen Coatings Nv Procede pour proteger des armatures en acier de structures en beton arme
WO2013062233A1 (fr) * 2011-10-28 2013-05-02 주식회사 화승알앤에이 Système de protection cathodique pour une structure en béton utilisant une anode sacrificielle sous-marine et une anode sacrificielle fixée à une enveloppe de protection

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN113789809A (zh) * 2021-09-16 2021-12-14 中国华能集团清洁能源技术研究院有限公司 防腐蚀的海上风电基础

Citations (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US485618A (en) * 1892-11-08 Apparatus for and process of refining copper by electricity
US651849A (en) * 1899-05-26 1900-06-19 Max Haas Electrolytic apparatus.
US2752308A (en) * 1952-08-18 1956-06-26 Smith Corp A O Cathodically protected water storage tank with safety shutoff
US2817634A (en) * 1953-09-22 1957-12-24 Texas Co Device for preventing corrosion
US3012958A (en) * 1958-04-17 1961-12-12 Patrol Valve Co Vitreous lined water tanks with sacrificial anodes
US3260661A (en) * 1965-04-01 1966-07-12 Koppers Co Inc Sacrificial metal pipe coverings
US3718554A (en) * 1969-09-18 1973-02-27 R Hull Cathodic protection for water tanks
US4506485A (en) * 1983-04-12 1985-03-26 State Of California, Department Of Transportation Process for inhibiting corrosion of metal embedded in concrete and a reinforced concrete construction
US4544465A (en) * 1983-10-26 1985-10-01 Union Oil Company Of California Galvanic anodes for submergible ferrous metal structures
US4699703A (en) * 1986-05-02 1987-10-13 Lauren Manufacturing Company Anodic boot for steel reinforced concrete structures

Patent Citations (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US485618A (en) * 1892-11-08 Apparatus for and process of refining copper by electricity
US651849A (en) * 1899-05-26 1900-06-19 Max Haas Electrolytic apparatus.
US2752308A (en) * 1952-08-18 1956-06-26 Smith Corp A O Cathodically protected water storage tank with safety shutoff
US2817634A (en) * 1953-09-22 1957-12-24 Texas Co Device for preventing corrosion
US3012958A (en) * 1958-04-17 1961-12-12 Patrol Valve Co Vitreous lined water tanks with sacrificial anodes
US3260661A (en) * 1965-04-01 1966-07-12 Koppers Co Inc Sacrificial metal pipe coverings
US3718554A (en) * 1969-09-18 1973-02-27 R Hull Cathodic protection for water tanks
US4506485A (en) * 1983-04-12 1985-03-26 State Of California, Department Of Transportation Process for inhibiting corrosion of metal embedded in concrete and a reinforced concrete construction
US4544465A (en) * 1983-10-26 1985-10-01 Union Oil Company Of California Galvanic anodes for submergible ferrous metal structures
US4699703A (en) * 1986-05-02 1987-10-13 Lauren Manufacturing Company Anodic boot for steel reinforced concrete structures

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
APOSTOLOS et al., STATE OF CALIFORNIA DEPARTMENT OF TRANSPORTATION REPORT, "Development Testing & Field Application of Metallized Cathodic Protection Coatings on Reinforced Concrete Substructures", pages 28-41. *
WHITING et al., NATIONAL COOPERATIVE HIGHWAY RESEARCH PROGRAM REPORT 234, "Gelvanic Cathodic Protection for Reinforced Concrete Bridge Decks", June 1981, pages 1-63. *

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2730751A1 (fr) * 1995-02-21 1996-08-23 Gen Coatings Nv Procede pour proteger des armatures en acier de structures en beton arme
BE1009152A5 (nl) * 1995-02-21 1996-12-03 Gen Coatings Werkwijze voor het tegenwerken van de corrosie van wapeningen in een betonmassa.
WO2013062233A1 (fr) * 2011-10-28 2013-05-02 주식회사 화승알앤에이 Système de protection cathodique pour une structure en béton utilisant une anode sacrificielle sous-marine et une anode sacrificielle fixée à une enveloppe de protection

Also Published As

Publication number Publication date
CA2101251A1 (fr) 1992-07-26
AU1342392A (en) 1992-08-27

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