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Intermittent Cathodic Protection for Steel Reinforced Concrete Bridges

Description: Thermal-sprayed zinc anodes are used for impressed current cathodic protection (ICCP) systems on Oregon's reinforced concrete coastal bridges to prevent chloride-induced corrosion damage. Thermal-sprayed zinc performs well as an ICCP anode but the service life of the zinc anode is directly related to the average current density used to operate the systems. After a ICCP system is turned off, the rebar in the concrete remains passive and protected for a period of time. Intermittent operation of CP systems is possible when continuous corrosion rate monitoring is used to identify conditions when the CP system needs to be turned on to reestablish protection conditions for the rebar. This approach applies CP protection only when needed and reflects the fact that external protection may not be needed for a range of environmental conditions. In doing so, intermittent CP would lower the average current necessary to protect rebar, increase the anode service life, and reduce the lifetime costs for protecting reinforced concrete bridges.
Date: January 1, 2002
Creator: Bullard, Sophie J.; Ziomek-Moroz, Margaret; Cramer, Stephen D.; Covino, Bernard S., Jr.; Holcomb, Gordon R.; Russell, James H. et al.
Partner: UNT Libraries Government Documents Department

Thermal Spray Coatings for Coastal Infrastructure

Description: Several protection strategies for coastal infrastructure using thermal-spray technology are presented from research at the Albany Research Center. Thermal-sprayed zinc coatings for anodes in impressed current cathodic protection systems are used to extend the service lives of reinforced concrete bridges along the Oregon coast. Thermal-sprayed Ti is examined as an alternative to the consumable zinc anode. Sealed thermal-sprayed Al is examined as an alternative coating to zinc dust filled polyurethane paint for steel structures.
Date: November 1, 1997
Creator: Holcomb, G.R.; Covino, Bernard S., Jr.; Cramer, S. D. & Bullard, S. J.
Partner: UNT Libraries Government Documents Department

Cathodic Protection of the Yaquina Bay Bridge

Description: The Yaquina Bay Bridge in Newport, Oregon, was designed by Conde B. McCullough and built in 1936. The 3,223-foot (982 m) structure is a combination of concrete arch approach spans and a steel through arch over the shipping channel. Cathodic protection is used to prevent corrosion damage to the concrete arches. The Oregon Department of Transportation (Oregon DOT) installed a carbon anode coating (DAC-85) on two of the north approach spans in 1985. This anode was operated at a current density of 6.6 mA/m2(0.6 mA/ft2). No failure of the conductive anode was observed in 1990, five years after application, or in 2000, 15 years after application. Thermal-sprayed zinc anodes 20 mils (0.5 mm) thick were applied to half the south approach spans beginning in 1990. Thermal-sprayed zinc anodes 15 mils (0.4 mm) thick were applied to the remaining spans in 1996. These anodes were operated at a current density of 2.2 mA/m2(0.2 mA/ft2). In 1999, four zones on the approach spans were included in a two-year field trial of humectants to improve zinc anode performance. The humectants LiNO3 and LiBr were applied to two zones; the two adjacent zones were left untreated as controls. The humectants substantially reduced circuit resistance compared to the controls.
Date: February 1, 2001
Creator: Bullard, Sophie J.; Cramer, Stephen D.; Covino, Bernard S., Jr.; Holcomb, Gordon R.; Russell, James H.; Laylor, H.M. et al.
Partner: UNT Libraries Government Documents Department

Cathodic protection of carbon steel in simulated geothermal environments

Description: The applicability of cathodic protection to mitigate corrosion of carbon steel in two different environments containing H{sub 2}S has been investigated using impressed current and sacrificial anode techniques. Results of impressed current tests conducted under potential control shows that the weight loss can be reduced significantly by shifting the potential of the metal 60 to 80 mV cathodic to the open circuit potential. The relationship between the applied current and the potential shift shows that the current requirement does not necessarily increase with the voltage shift, thus implying that the cost of cathodic protection may not increase in proportion to the protection achieved. The feasibility of using zinc as a sacrificial anode in the environment of interest has also been studied.
Date: October 8, 1982
Creator: Bandy, R. & van Rooyen, D.
Partner: UNT Libraries Government Documents Department

System for storing cathodic protection measurement data

Description: This paper describes a custom cathodic protection (CP) database, and discusses how this combination of data structure and software improves the ability to analyze cathodic protection. This may be a unique solution to the task of managing CP data, and may have value to others. This paper is primarily about the database design, and not about cathodic protection, per se. Every database project is a balancing act. A developer can create custom software that performs complex opcrafions requiring modest operator skills. On the other hand, custom software is expensive to both create and maintain. The Hanford CP data system will be used primarily by one person, the CP Engineer. It was concluded that this position could be trained to use off-the-shelf, general purpose database to store data, and spreadsheet software to perform analyses. The database product allows flexibility in data reporting, and enforces referential integrity. The spreadsheet allows many display options. Especially useful are the graphics. This solution entailed minimal computer coding and may lend itself to adoption by others. The data structure was designed by a database application developer, with close guidance from the CP engineer. The system will require modest amounts of attention from computer support staff, primarily for new query development. The data structures are provided in this report, and are available electronically.
Date: December 2, 1996
Creator: Bowman, T.J., Westinghouse Hanford
Partner: UNT Libraries Government Documents Department

A performance evaluation of coating systems for long term aqueous immersion service

Description: The static immersion of coated steel panels in various media representative of chemical and waste processes around the Oak Ridge Y-12 Plant was terminated after 16 months exposure for evaluation of coating performance and comparison with observations collected following 1, 6, and 11 months exposure. In each environment, a wide range of coating performance was observed, including some coatings unsuitable for use in the test environment (despite the high recommendation of the vendor). Further, coating performance as a function of time suggests a test duration of at least several months is required to fully assess candidate coating performance for specific applications. The performance of many coatings, particularly in the most alkaline environment, was adversely affected by the imposition of supplemental cathodic protection on the coated test panels.
Date: November 8, 1994
Creator: Pawel, S.J.
Partner: UNT Libraries Government Documents Department

REALTIME MONITORING OF PIPELINES FOR THIRD-PARTY CONTACT

Description: Third-party contact with pipelines (typically caused by contact with a digging or drilling device) can result in mechanical damage to the pipe, in addition to coating damage that can initiate corrosion. Because this type of damage often goes unreported and can lead to eventual catastrophic failure of the pipe, a reliable, cost-effective method is needed for monitoring and reporting third-party contact events. The impressed alternating cycle current (IACC) pipeline monitoring method consists of impressing electrical signals on the pipe by generating a time-varying voltage between the pipe and the soil at periodic locations where pipeline access is available. The signal voltage between the pipe and ground is monitored continuously at receiving stations located some distance away. Third-party contact to the pipe that breaks through the coating changes the signal received at the receiving stations. In this project, the IACC monitoring method is being developed, tested, and demonstrated. Work performed to date includes (1) a technology assessment, (2) development of an IACC model to predict performance and assist with selection of signal operating parameters, (3) Investigation of potential interactions with cathodic protection systems, and (4) experimental measurements on buried pipe at a test site as well as on an operating pipeline. Initial results show that simulated contact can be detected. Future work will involve further refinement of the method and testing on operating pipelines.
Date: October 1, 2004
Creator: Burkhardt, Gary L. & Crouch, Alfred E.
Partner: UNT Libraries Government Documents Department

REALTIME MONITORING OF PIPELINES FOR THIRD-PARTY CONTACT

Description: Third-party contact with pipelines (typically caused by contact with a digging or drilling device) can result in mechanical damage to the pipe, in addition to coating damage that can initiate corrosion. Because this type of damage often goes unreported and can lead to eventual catastrophic failure of the pipe, a reliable, cost-effective method is needed for monitoring and reporting third-party contact events. The impressed alternating cycle current (IACC) pipeline monitoring method consists of impressing electrical signals on the pipe by generating a time-varying voltage between the pipe and the soil at periodic locations where pipeline access is available. The signal voltage between the pipe and ground is monitored continuously at receiving stations located some distance away. Third-party contact to the pipe that breaks through the coating changes the signal received at the receiving stations. In this project, the IACC monitoring method is being developed, tested, and demonstrated. Work performed to date includes (1) a technology assessment, (2) development of an IACC model to predict performance and assist with selection of signal operating parameters, (3) Investigation of potential interactions with cathodic protection systems, and (4) experimental measurements on buried pipe at a test site as well as on an operating pipeline. Initial results showed that IACC signals could be successfully propagated over a distance of 3.5 miles, and that simulated contact can be detected up to a distance of 0.7 mile. Unexpected results were that the electrical impedance from the operating pipelines to the soil was very low and, therefore, the changes in impedance and signal resulting from third-party contact were unexpectedly low. Future work will involve further refinement of the method to resolve the issues with small signal change and additional testing on operating pipelines.
Date: April 1, 2005
Creator: Burkhardt, Gary L. & Crouch, Alred E.
Partner: UNT Libraries Government Documents Department

REALTIME MONITORING OF PIPELINES FOR THIRD-PARTY CONTACT

Description: Third-party contact with pipelines (typically caused by contact with a digging or drilling device) can result in mechanical damage to the pipe, in addition to coating damage that can initiate corrosion. Because this type of damage often goes unreported and can lead to eventual catastrophic failure of the pipe, a reliable, cost-effective method is needed for monitoring and reporting third-party contact events. The impressed alternating cycle current (IACC) pipeline monitoring method consists of impressing electrical signals on the pipe by generating a time-varying voltage between the pipe and the soil at periodic locations where pipeline access is available. The signal voltage between the pipe and ground is monitored continuously at receiving stations located some distance away. Third-party contact to the pipe that breaks through the coating changes the signal received at the receiving stations. In this project, the IACC monitoring method is being developed, tested, and demonstrated. Work performed to date includes (1) a technology assessment, (2) development of an IACC model to predict performance and assist with selection of signal operating parameters, (3) investigation of potential interactions with cathodic protection systems, and (4) experimental measurements on operating pipelines. Based on information recently found in published studies, it is believed that the operation of IACC on a pipeline will cause no interference with CP systems. Initial results on operating pipelines showed that IACC signals could be successfully propagated over a distance of 3.5 miles, and that simulated contact can be detected up to a distance of 1.4 miles, depending on the pipeline and soil conditions.
Date: October 1, 2005
Creator: Burkhardt, Gary L. & Crouch, Alfred E.
Partner: UNT Libraries Government Documents Department

Cathodic protection -- Rectifier 47

Description: This Acceptance Test Procedure (ATP) has been prepared to demonstrate that the cathodic protection system functions as required by project criteria. The cathodic protection system is for the tank farms at the Hanford Reservation. The tank farms store radioactive waste.
Date: June 14, 1995
Creator: Lane, W.M.
Partner: UNT Libraries Government Documents Department

Cathodic protection for geothermal wells

Description: A study was conducted to determine the current requirements for cathodic protection of geothermal wells. Oil well technology was applied in this study. Results of laboratory tests and field tests are presented. Attenuation calculations indicate that the cathodic protection current determined from field tests would protect the specific individual geothermal well.
Date: October 8, 1982
Creator: Ohnysty, B.; Slattery, D.G. & Morris, M.
Partner: UNT Libraries Government Documents Department

CATHODIC REDUCTION OF PASSIVE FILMS ON IRON IN BORATE AND PHOSPHATE BUFFER PH 8.4: DIFFERENT MECHANISMS REVEALED BY IN SITU TECHNIQUES.

Description: The electrochemical behavior of passive Fe and thin, sputter-deposited films of Fe{sub 2}O{sub 3} was studied in borate and phosphate buffer pH 8.4 solutions. Cyclic voltammograms and in situ light absorption measurements--which enable the monitoring of the oxide film thickness--indicate a similar behavior of the Fe electrode in both pH 8.4 solution, especially a presence of a oxide-free surface at low cathodic potentials. However, X-ray absorption near edge structure (XANES) studies--which allow a simultaneous monitoring of changes in the samples' average valency and thickness - reveal that the reactions taking place during reduction of the passive film on iron are completely different for the two electrolytes. In borate buffer (pH 8.4), reduction leads to a complete dissolution of the passive film and the end product of reduction is soluble Fe(2+). In phosphate buffer (pH 8.4), there is no dissolution in a direct step to low cathodic potentials, but the resulting reduction product is metallic iron. Hence, the formation of the bare oxide-free metal surface at cathodic potentials takes place by different mechanisms in the two pH 8.4 solutions, depending on the type of anion present in the solution.
Date: March 25, 2001
Creator: SCHMUKI,P.; VIRTANEN,S. & ISAACS,H.S.
Partner: UNT Libraries Government Documents Department

Cathodic protection -- Rectifier 46

Description: This Acceptance Test Procedure (ATP) has been prepared to demonstrate that the cathodic protection system functions as required by project criteria. The cathodic protection system is for the tank farms on the Hanford Reservation. The tank farms store radioactive waste.
Date: June 14, 1995
Creator: Lane, W.M.
Partner: UNT Libraries Government Documents Department

Cathodic protection -- Addition of 6 anodes to existing rectifier 31

Description: This Acceptance Test Procedure (ATP) has been prepared to demonstrate that the cathodic protection system additions are installed, connected, and function as required by project criteria. The cathodic protection system is for the tank farms on the Hanford Reservation. The tank farms store radioactive wastes.
Date: June 14, 1995
Creator: Lane, W.M.
Partner: UNT Libraries Government Documents Department

1999 Annual Cathodic Protection Survey Report for PFP

Description: This cathodic protection (CP) report documents the results of the 1999 annual CP survey of the underground piping within PFP property. An annual survey of CP systems is required by Washington Administrative Code (WAC). A spreadsheet to document the 1999 annual survey polarization data is included in this report. Graphs are included to trend the cathodic voltages and the polarization voltages at each test station on PFP property. The trending spans from 1994 to 1999. Graphs are also included to trend voltage and amperage outputs of each rectifier during the annual surveys. During the annual survey, resistance testing between the underground piping was conducted at each test station. The testing showed that all piping (with test leads into the test stations) was continuous with every pipe represented in the test stations. The resistance data is not documented in this report but can be accessed in work package 22-99-01003. During the annual survey, the wiring configurations of anode junction boxes AJB(R45-1) and AJB(45-1) were documented. The sketches can be accessed from the JCS work record of work package 22-99-01003. Analysis, conclusions, and recommendations of the 1999 annual CP survey results are included in this report.
Date: October 3, 2000
Creator: BOWMAN, T.J.
Partner: UNT Libraries Government Documents Department

Performance of Zinc Anodes for Cathodic Protection of Reinforced Concrete Bridges

Description: Operation of thermal spray zinc (Zn) anodes for cathodic protection (CP) of reinforced concrete structures was investigated in laboratory and field studies conducted by the Albany Research Center (ARC) in collaboration with the Oregon Department of Transportation. The purposes of the research presented in this report were: evaluate the need for preheating concrete to improve the adhesion of the anode; estimate the service life of thermal spray Zn CP anodes; determine the optimum thickness for Zn CP anodes; characterize the anode-concrete interfacial chemistry; and correlate field and laboratory results. Laboratory studies involved accelerated electrochemical aging of thermal sprayed Zn anodes on concrete slabs, some of which were periodically wetted while others were unwetted. Concrete used in the slabs contained either 1.2 or 3 kg NaCl /m3 (2 or 5 lbs NaCl /yd3) as part of the concrete mix design. The Zn anodes were applied to the slabs using the twin wire arc-spray technique. Half of the slabs were preheated to 120-160 C (250-320 F) to improve the initial Zn anode bond strength and the other half were not. Accelerated aging was done at a current density of 0.032 A/m2 (3 mA/ft2), 15 times that used on Oregon DOT Coastal bridges, i.e, . 0.0022 A/m2 (0.2 mA/ft2) Cores from the Cape Creek Bridge (OR), the Richmond San Rafael Bridge (CA), and the East Camino Underpass (CA) were used to study the anode-concrete interfacial chemistry, to relate the chemistry to electrochemical age at the time of sampling, and to compare the chemistry of the field anodes to the chemistry of anodes from the laboratory studies. Cores from a CALTRANS study of a silane sealant used prior to the application of the Zn anodes and cores with galvanized rebar from the Longbird Bridge (Bermuda) were also studied. Aged laboratory and field anodes were ...
Date: March 1, 2002
Creator: Covino, Bernard S., Jr.; Cramer, Stephen D.; Bullard, Sophie J.; Holcomb, Gordon R.; Russell, James H.; Collins, W. Keith et al.
Partner: UNT Libraries Government Documents Department

Thermal-sprayed zinc anodes for cathodic protection of steel-reinforced concrete bridges

Description: Thermal-sprayed zinc anodes are being used in Oregon in impressed current cathodic protection (ICCP) systems for reinforced concrete bridges. The U.S. Department of Energy, Albany Research Center, is collaborating with the Oregon Department of Transportation (ODOT) to evaluate the long-term performance and service life of these anodes. Laboratory studies were conducted on concrete slabs coated with 0.5 mm (20 mil) thick, thermal-sprayed zinc anodes. The slabs were electrochemically aged at an accelerated rate using an anode current density of 0.032 A/m2 (3mA/ft2). Half the slabs were preheated before thermal-spraying with zinc; the other half were unheated. Electrochemical aging resulted in the formation at the zinc-concrete interface of a thin, low pH zone (relative to cement paste) consisting primarily of ZnO and Zn(OH)2, and in a second zone of calcium and zinc aluminates and silicates formed by secondary mineralization. Both zones contained elevated concentrations of sulfate and chloride ions. The original bond strength of the zinc coating decreased due to the loss of mechanical bond to the concrete with the initial passage of electrical charge (aging). Additional charge led to an increase in bond strength to a maximum as the result of secondary mineralization of zinc dissolution products with the cement paste. Further charge led to a decrease in bond strength and ultimately coating disbondment as the interfacial reaction zones continued to thicken. This occurred at an effective service life of 27 years at the 0.0022 A/m2 (0.2 mA/ft2) current density typically used by ODOT in ICCP systems for coastal bridges. Zinc coating failure under tensile stress was primarily cohesive within the thickening reaction zones at the zinc-concrete interface. There was no difference between the bond strength of zinc coatings on preheated and unheated concrete surfaces after long service times.
Date: January 1, 1996
Creator: Bullard, Sophie J.; Covino, Bernard S., Jr.; Cramer, Stephen D. & McGill, Galen E. (Oregon Dept. of Transportation)
Partner: UNT Libraries Government Documents Department

Impacts of cathodic protection on waste package performance

Description: The current design concept for a multi-barrier waste container for the potential repository at Yucca Mountain, Nevada, calls for an outer barrier of 100 mm thick corrosion-allowance material (CAM) (carbon steel) and an inner barrier of 20 mm thick corrosion-resistant material (CRM) (Alloy 825). Fulfillment of the NRC subsystem requirements (10 CFR 60.113) of substantially complete containment and controlled release of radionuclides from the engineered barrier system (EBS) will rely mostly upon the robust waste container design, among other EBS components. In the current waste container design, some degree of cathodic protection of CRM will be provided by CAM. This paper discusses a sensitivity case study for the impacts of cathodic protection of the inner barrier by the outer barrier on the performance of waste package.
Date: June 1, 1996
Creator: Atkins, J.E.; Lee, J.H. & Andrews, R.W.
Partner: UNT Libraries Government Documents Department