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Title: Field Trial of impressed current, sacrificial anode, constant voltage and intermittent cathodic protection on a steel reinforced coastal bridge

Abstract

Equipment has been designed and installed for a field trial being conducted on a coastal reinforced concrete bridge with a newly installed cathodic protection (CP) system. The purpose of the field trial is to determine the optimum form of intermittent CP for protecting coastal bridges. The forms of CP that were considered for the field trial are: (1) impressed current CP as the control; (2) currentinterrupted ICCP; (3) corrosion rate monitoring device controlled ICCP; (4) constant voltage CP; and (5) sacrificial anode CP. Once the test is initiated, the performance of these four forms of CP on a coastal RC bridge and their effectiveness in providing protection to reinforcing steel will be is compared with that achieved by present Oregon Department of Transportation ICCP practices. Details are presented on the set up of the experiment and the logic used to control CP intermittently. The field trial is scheduled to be started early 2007.

Authors:
; ; ; ; ;  [1];  [2];  [2]
  1. (Intercorr International Inc.)
  2. (ODOT)
Publication Date:
Research Org.:
National Energy Technology Laboratory (NETL), Pittsburgh, PA, and Morgantown, WV; Oregon Department of Transportation (ODOT), Salem, OR
Sponsoring Org.:
USDOE - Office of Fossil Energy (FE); ODOT
OSTI Identifier:
913179
Report Number(s):
DOE/NETL-IR-2007-092
TRN: US200802%%577
Resource Type:
Conference
Resource Relation:
Conference: Corrosion/2007, Nashville, TN, Mar. 11-15, 2007
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; ANODES; CATHODIC PROTECTION; CORROSION; MONITORING; PERFORMANCE; REINFORCED CONCRETE; STEELS; US DOT

Citation Formats

Bullard, S.J., Covino, B.S., Jr., Williamson, K.M., Holcomb, G.R., Ziomek-Moroz, M., Eden, D.A., Cryer, C.B., and Tran, H. Field Trial of impressed current, sacrificial anode, constant voltage and intermittent cathodic protection on a steel reinforced coastal bridge. United States: N. p., 2007. Web.
Bullard, S.J., Covino, B.S., Jr., Williamson, K.M., Holcomb, G.R., Ziomek-Moroz, M., Eden, D.A., Cryer, C.B., & Tran, H. Field Trial of impressed current, sacrificial anode, constant voltage and intermittent cathodic protection on a steel reinforced coastal bridge. United States.
Bullard, S.J., Covino, B.S., Jr., Williamson, K.M., Holcomb, G.R., Ziomek-Moroz, M., Eden, D.A., Cryer, C.B., and Tran, H. Thu . "Field Trial of impressed current, sacrificial anode, constant voltage and intermittent cathodic protection on a steel reinforced coastal bridge". United States. doi:.
@article{osti_913179,
title = {Field Trial of impressed current, sacrificial anode, constant voltage and intermittent cathodic protection on a steel reinforced coastal bridge},
author = {Bullard, S.J. and Covino, B.S., Jr. and Williamson, K.M. and Holcomb, G.R. and Ziomek-Moroz, M. and Eden, D.A. and Cryer, C.B. and Tran, H.},
abstractNote = {Equipment has been designed and installed for a field trial being conducted on a coastal reinforced concrete bridge with a newly installed cathodic protection (CP) system. The purpose of the field trial is to determine the optimum form of intermittent CP for protecting coastal bridges. The forms of CP that were considered for the field trial are: (1) impressed current CP as the control; (2) currentinterrupted ICCP; (3) corrosion rate monitoring device controlled ICCP; (4) constant voltage CP; and (5) sacrificial anode CP. Once the test is initiated, the performance of these four forms of CP on a coastal RC bridge and their effectiveness in providing protection to reinforcing steel will be is compared with that achieved by present Oregon Department of Transportation ICCP practices. Details are presented on the set up of the experiment and the logic used to control CP intermittently. The field trial is scheduled to be started early 2007.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Thu Mar 01 00:00:00 EST 2007},
month = {Thu Mar 01 00:00:00 EST 2007}
}

Conference:
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  • This paper addresses both safe cathodic protection limits for pre-stressing steel in concrete given the concern of hydrogen embrittlement (HE) and the adequacy of cathodic protection using established criteria. Impressed current cathodic protection was applied to laboratory scale pilings at current densities ranging from 0.1 to 2.5 {micro}A/cm{sup 2} via a skirt anode located at the waterline. Adequate cathodic protection was achieved at positions ranging from 25 cm above to 50 cm below the waterline, according to the 100 mV depolarization criterion, at an apparent applied current density of 0.33 {micro}A/cm{sup 2}. However, the {minus}780 mV{sub SCE} criterion was notmore » met for currents as high as 1.33 {micro}A/cm{sup 2} for these positions. Hydrogen production, absorption, and permeation in steel was first observed via embedded hydrogen sensors, located 50 cm and 25 cm above the waterline, at an applied current density of 0.33 {micro}A/cm{sup 2}. The observation of hydrogen production verifies the concerns that the local oxygen concentration may be readily depleted at modest cathodic protection levels and that local pH levels may be below 12.5. Experimentation presented here, as well as within the literature, has demonstrated that steel crevice corrosion is readily initiated within chloride contaminated concrete prior to the application of cathodic protection, and that this corrosion is accompanied by an acidification of the local environment to a pH of 6 or below due to ferrous ion hydrolysis. The mobile subsurface hydrogen concentration present within the steel reinforcement was determined for each applied cathodic current density. Although hydrogen production and uptake occurred at current densities as low as 0.33 {micro}A/cm{sup 2}, the critical hydrogen concentration for embrittlement (2 {times} 10{sup {minus}7} mol H/cm{sup 3}) was not exceeded at area averaged current densities as high as 1.33 {micro}A/cm{sup 2}.« less
  • Safe cathodic protection (CP) limits for prestressing steel in concrete and the adequacy of CP using established criteria were evaluated in regard to hydrogen embrittlement (HE). Impressed-current CP was applied to laboratory scale pilings at current densities from 0.1 {micro}A/cm{sup 2} to 3.0 {micro}A/cm{sup 2} via a skirt anode located at the waterline. Adequate CP was achieved at positions 25 cm (9.8 in.) above to 50 cm (19.7 in.) below the waterline, according to the 100-mV depolarization criterion, at an apparent applied current density of 0.33 {micro}A/cm{sup 2}. However, the {minus}780 mV{sub SCE} criterion was not met for currents asmore » high as 1.33 {micro}A/cm{sup 2} for these positions. Hydrogen production, absorption, and permeation in steel first was observed via embedded hydrogen sensors 50 cm and 25 cm above the water line at an applied current density of 0.33 {micro}A/cm{sup 2}. Observation of hydrogen production verified concerns that the local oxygen concentration might be depleted readily at modest CP levels and that local pH levels may be below 12.5. Experimentation demonstrated that steel crevice corrosion was initiated readily within chloride (Cl{sup {minus}})-contaminated concrete prior to CP application and that this corrosion was accompanied by acidification of the local environment to pH {le} 6 as a result of ferrous ion (Fe{sup 2+}) hydrolysis. The mobile subsurface hydrogen concentration present within the steel reinforcement was determined for each applied cathodic current density. Although hydrogen production and uptake occurred at current densities as low as 0.33 {micro}A/cm{sup 2}, the critical hydrogen concentration for embrittlement (i.e., 2 {times} 10{sup {minus}7} mol H/cm{sup 3}, as determined in prior research for bluntly notched prestressing steel) was not exceeded at area averaged current densities <1.33 {micro}A/cm{sup 2}.« less
  • Various configurations of sacrificial zinc anodes have been successfully used to provide cathodic protection in the tidal zone of steel reinforced concrete structures. Studies conducted by the Florida Department of Transportation have shown that zinc anodes configured in simple fashion can provide long term cathodic protection. These simple systems represent an attractive alternative to conventional cathodic protection where rectifiers are used. This paper discusses a cathodic protection system comprised of zinc sheet anodes used in conjunction with a submerged bulk zinc anode. An overview of long term performance is presented along with estimated service life and costs.
  • The problem of corrosion of the reinforcing steel in concrete is recognized as a worldwide problem. In particular, these is extensive corrosion in residential and commercial balconies in tropical, coastal areas of the US, especially in Florida. A system of cathodic protection of reinforcing steel in concrete utilizing a sacrificial zinc anode and ionically conductive adhesive is described. Installation and monitoring of two condominium balconies in south Florida will be described, including instant-off and depolarization measurements over 18 months.
  • A sacrificial magnesium anode cathodic protection system has been installed to provide corrosion protection to an underground steel reinforced concrete structure. The system was installed to abate the development of corrosion on steel reinforcing bars that were left exposed to soil and water as a result of concrete placement difficulties. The system has been in service for a period of five months and exhibits excellent performance. This paper reports on the design, installation, materials used, and system performance for the period in service.