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Title: EFFECT OF CATHODIC POLARIZATION AND SEA WATER VELOCITY UPON CALCAREOUS DEPOSIT FORMATION ON MILD STEEL.
Creator: WOLFSON, STEPHEN LANCE., Florida Atlantic University, Hartt, William H.
Abstract/Description: To investigate environmental conditions which influence the type and formation of calcareous deposits, AISI 1010 steel specimens were exposed in sea water at constant velocities and controlled potentials. Chemistry and thickness of the deposits which formed as a result of cathodic polarization of steel in sea water were determined. These variables were found to be a function of velocity and controlled potential with film thickness decreasing as velocity increased for all potentials considered...
Show moreTo investigate environmental conditions which influence the type and formation of calcareous deposits, AISI 1010 steel specimens were exposed in sea water at constant velocities and controlled potentials. Chemistry and thickness of the deposits which formed as a result of cathodic polarization of steel in sea water were determined. These variables were found to be a function of velocity and controlled potential with film thickness decreasing as velocity increased for all potentials considered. This behavior is interpreted in terms of variations in pH at the metal surface. A mass transfer analysis is presented which projects the pH at the metal surface as a function of velocity and controlled potential. Scanning electron micrographs are also included to give information regarding the nature and type of deposits. The experimental results are discussed within the frame of accepted concepts of sea water cathodic protection.
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Date Issued: 1978
PURL: http://purl.flvc.org/fcla/dt/13954
Subject Headings: Cathodic protection
Format: Document (PDF)

Title: Cathodic polarization behavior of mild steel exposed to selected flow velocities and slope parameters in natural seawater.
Creator: Hugus, G. Dickson, IV., Florida Atlantic University, Hartt, William H.
Abstract/Description: Twenty-four test cells arranged in a pipe flow setup were assembled to investigate the effect of seawater velocity on the polarization behavior of galvanically polarized mild steel. Each 1023 steel pipe specimen of 10.8 em ID was coupled via a current limiting resistor to a mercury activated aluminum anode and exposed to a velocity of either 0.03, 0.09 or 0.30 m/s. The resistors were sized such that polarization was controlled according to one of six slope parameters. Steady state potential...
Show moreTwenty-four test cells arranged in a pipe flow setup were assembled to investigate the effect of seawater velocity on the polarization behavior of galvanically polarized mild steel. Each 1023 steel pipe specimen of 10.8 em ID was coupled via a current limiting resistor to a mercury activated aluminum anode and exposed to a velocity of either 0.03, 0.09 or 0.30 m/s. The resistors were sized such that polarization was controlled according to one of six slope parameters. Steady state potential and maintenance current density values were determined, and a steady state potential vs. current density curve was established for specimens in each velocity. Some specimens experienced a rise in cathode potential and current density after an apparent steady state had been reached. This was probably related to the influence of velocity on the protectiveness of the calcareous deposit. Of the specimens that experienced a rise in steady state potential and current density, a few were later observed to decrease in potential and current density and reach steady state. Steady state current density vs. velocity plots of specimens at steady state potentials of -0.78, -0.88 and -0.98 V showed that current density was directly proportional to velocity as well as relatively insensitive to potential. Ficks' first law was utilized in conjunction with an empirically derived dimensionless correlation that characterizes the behavior between fluid velocity and mass transfer of molecular species from the bulk solution to the cathode surface in turbulent seawater pipe flow. Calcareous deposit porosity constants were calculated and it was surmised that as velocity increased by a factor of three, the porosity of the deposits near 0.78 and -0.89 V increased by multiples of about two on average. Porosity at the above potentials increased with decreasing potential by a factor of a little over two. SEM micrographs were made and EDX analyses were performed on the calcareous deposits of selected specimens.
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Date Issued: 1997
PURL: http://purl.flvc.org/fcla/dt/15501
Subject Headings: Cathodic protection, Seawater corrosion, Marine steel
Format: Document (PDF)

Title: Cathodic protection modeling of marine pipelines.
Creator: Lysogorski, Diane K., Florida Atlantic University, Hartt, William H., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: A governing equation for potential attenuation along a pipeline cathodically protected by identical, evenly-spaced, spherical anodes is developed. The numerical solution, obtained using a coordinate based mapping (CoMB) finite difference method (FDM), can be used to predict the potential profile of a pipeline. In addition, a modified version of Ohm's Law is developed to provide an improved approach to design of pipeline CP systems. Both approaches address anode-electrolyte, coating...
Show moreA governing equation for potential attenuation along a pipeline cathodically protected by identical, evenly-spaced, spherical anodes is developed. The numerical solution, obtained using a coordinate based mapping (CoMB) finite difference method (FDM), can be used to predict the potential profile of a pipeline. In addition, a modified version of Ohm's Law is developed to provide an improved approach to design of pipeline CP systems. Both approaches address anode-electrolyte, coating-polarization, and metallic path resistance, but the latter neglects to address the potential gradient associated with the one-dimensional nature of pipelines. These two approaches were compared to results from existing potential prediction methods and Boundary Element Methods (BEM). Furthermore, a procedure was developed to calculate the resistance of rectangular conductor arrays. This procedure was utilized to calculate the resistance of an anode sled. Combination of the first principles based equation and the rectangular array resistance procedure allows one to predict the potential profile for a pipeline protected by identical, evenly-spaced, anode sleds.
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Date Issued: 2001
PURL: http://purl.flvc.org/fcla/dt/12850
Subject Headings: Underwater pipelines, Pipelines--Cathodic protection
Format: Document (PDF)

Title: Characterization of steel cathodic polarization in seawater and its applications in offshore structure cathodic protection design.
Creator: Wang, Weiqing., Florida Atlantic University, Hartt, William H., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: Laboratory experiments have been performed to characterize the effects of initial current density and selected variables (initial current density, temperature and surface treatment) upon the cathodic polarization behavior of API 2H Grade 42 steel in natural sea water. The procedure involved galvanic coupling of a cylindrical steel specimen to a larger diameter aluminum sacrificial anode ring through an external resistor, which offset the otherwise impractically small anode/cathode surface...
Show moreLaboratory experiments have been performed to characterize the effects of initial current density and selected variables (initial current density, temperature and surface treatment) upon the cathodic polarization behavior of API 2H Grade 42 steel in natural sea water. The procedure involved galvanic coupling of a cylindrical steel specimen to a larger diameter aluminum sacrificial anode ring through an external resistor, which offset the otherwise impractically small anode/cathode surface area ratio and permitted the desired initial current density to be realized. In the initial polarization stage the change in potential versus current density data with time was found to be linear with a slope equal to the product of the total circuit resistance and cathode surface area and with the vertical intercept corresponding to the anode open circuit potential. Lower temperature or increased flow resulted in reduced polarization and a relatively high current density, but data for experiments employing a particular resistance conformed to straight lines with the same slope R[ext] x A[c] (external resistance times cathode surface area). Some experiments exhibited concave behavior at longer test duration. An explanation for the linear interdependence of potential and current density and the following concave behavior is presented. The laboratory experiments were compared with offshore structure survey results. It is projected that the potential-current density behavior of galvanic cathodic protection (CP) systems of different geometries can be quantitatively interrelated through this slope parameter. Implications of the data are discussed within the context of cathodic protection design, rapid polarization and system performance for offshore structures.
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Date Issued: 1994
PURL: http://purl.flvc.org/fcla/dt/12362
Subject Headings: Steel--Cathodic protection, Seawater, Offshore structures
Format: Document (PDF)

Title: THE PROPERTIES OF CALCAREOUS DEPOSITS FORMED ON METAL SURFACE IN SEA WATER UNDER CATHODIC PROTECTION AT DIFFERENT POTENTIALS AND CURRENT DENSITIES.
Creator: Luo, Jiunn-Shyong, Florida Atlantic University, Lee, Rupert U., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: The influence of impressed current density and potential upon the nature of calcareous deposits formed . on a cathodic steel surface has been investigated. The experiments included potentiostatic, galvanostatic and mixed mode combined galvanostatic and potentiostatic techniques for affecting polarization. Specific attention was focused upon the thickness, morphology and composition of the deposits. A Mg 2+ depletion model has been developed as a possible explanation for the nucleation and...
Show moreThe influence of impressed current density and potential upon the nature of calcareous deposits formed . on a cathodic steel surface has been investigated. The experiments included potentiostatic, galvanostatic and mixed mode combined galvanostatic and potentiostatic techniques for affecting polarization. Specific attention was focused upon the thickness, morphology and composition of the deposits. A Mg 2+ depletion model has been developed as a possible explanation for the nucleation and growth behavior of calcareous deposits formed under combined mode operation.
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Date Issued: 1987
PURL: http://purl.flvc.org/fcla/dt/14376
Subject Headings: Metals--Cathodic protection, Chemical oceanography, Calcium
Format: Document (PDF)

Title: ONCE-THROUGH VERSUS RECIRCULATING SEAWATER TESTING OF CATHODICALLY PROTECTED STEEL FOR CALCAREOUS DEPOSIT FORMATION.
Creator: NYE, TRACY LOUISE., Florida Atlantic University, Smith, Samuel W., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: The efficiency of cathodic protection of steel in seawater is partially due to calcareous deposits. To better understand deposits, expericents are conducted testing the effects of variables such as tecperature, velocity, and applied current, on film formation and protection capabilities. It is the intent of this thesis to investigate differences in using recirculating seawater rather than once-through seawater in these experiments. It is believed that these differences were caused by an...
Show moreThe efficiency of cathodic protection of steel in seawater is partially due to calcareous deposits. To better understand deposits, expericents are conducted testing the effects of variables such as tecperature, velocity, and applied current, on film formation and protection capabilities. It is the intent of this thesis to investigate differences in using recirculating seawater rather than once-through seawater in these experiments. It is believed that these differences were caused by an increase in dissolved organics in the recirculating bath. Data is in the form of current needed to maintain a potential of -1.0v SCE since differences in current help describe differences in film properties.
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Date Issued: 1984
PURL: http://purl.flvc.org/fcla/dt/14224
Subject Headings: Steel--Cathodic protection, Steel--Testing
Format: Document (PDF)

Title: Prestressing steel to concrete bond degradation due to cathodic polarization.
Creator: Joubert, Emmanuel., Florida Atlantic University, Hartt, William H.
Abstract/Description: Experiments were conducted to evaluate occurrence of any deterioration of prestressing steel tendon to concrete bond as a consequence of cathodic polarization. Pretensionned concrete specimens were cathodically polarized with current densities ranging from 50 to 5000 m^2 of steel while exposed to a constant flow of natural sea water. The concrete and steel dimensional changes were monitored by strain gages mounted on the tendons and embedded in the concrete. Contractions of the steel of 25 to...
Show moreExperiments were conducted to evaluate occurrence of any deterioration of prestressing steel tendon to concrete bond as a consequence of cathodic polarization. Pretensionned concrete specimens were cathodically polarized with current densities ranging from 50 to 5000 m^2 of steel while exposed to a constant flow of natural sea water. The concrete and steel dimensional changes were monitored by strain gages mounted on the tendons and embedded in the concrete. Contractions of the steel of 25 to 50 percent of the initial tensioning were recorded after 17 to 36 MC/m^2 were transferred to the tendons on specimens polarized at the highest currents. This corresponds to 54 to 114 years of polarization at 10mA/m^2 if bond loss was solely dependent on the charge transfer. It was noticed that the smaller the current, the more the charge that was transferred before steel contraction began. These results imply that cathodic polarization should impose no threat to the prestressing steel-to-concrete bond on typical structures over their expected lifetime.
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Date Issued: 1995
PURL: http://purl.flvc.org/fcla/dt/15209
Subject Headings: Prestressed concrete, Steel--Corrosion, Cathodic protection
Format: Document (PDF)

Title: Potential attenuation and anode current output determination alternatives for galvanic anode cathodic protection upon offshore pipelines.
Creator: Bethune, Keith P., Florida Atlantic University, Hartt, William H.
Abstract/Description: A recently developed equation governing cathodic polarization attenuation along a pipeline protected by galvanic anodes is first solved. The solution is based upon a numerical finite difference method (FDM). The resulting subroutine computes the polarization along the cathode and the corresponding anode current output based upon the physical design variables and electrochemical properties of the cathode. Validation of this method is accomplished through comparisons with a proven existing...
Show moreA recently developed equation governing cathodic polarization attenuation along a pipeline protected by galvanic anodes is first solved. The solution is based upon a numerical finite difference method (FDM). The resulting subroutine computes the polarization along the cathode and the corresponding anode current output based upon the physical design variables and electrochemical properties of the cathode. Validation of this method is accomplished through comparisons with a proven existing method for attenuation prediction, namely the Boundary Element Method (BEM). As both the FDM and BEM solutions are mathematically complex and time consuming, it is then demonstrated that a modified form of Ohm's Law that quantitatively interrelates (1) design life, (2) anode size, weight, and properties, (3) pipe size, current demand, and coating quality, (4) sea water resistivity, (5) magnitude of polarization, and (6) anode spacing is sufficient for design purposes where metallic resistance of the pipeline itself is negligible. This new method can be easily adapted in a spreadsheet type analysis as no numerical subroutine is necessary. One size pipeline of varying lengths is analyzed using these methods for comparisons and validation and the effect of metallic resistance on attenuation profiles is examined. It is concluded that for small diameter pipelines with anode spacing up to 800 m metallic resistance is negligible, and thus all three methods can be used with reasonable confidence for spacings below 800 m. An analysis to illustrate the effect of a stratified electrolyte in the vicinity of the pipeline has been initiated and preliminary results are also presented.
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Date Issued: 2000
PURL: http://purl.flvc.org/fcla/dt/12672
Subject Headings: Underwater pipelines, Pipelines--Cathodic protection
Format: Document (PDF)

Title: The assessment of bond for cathodically polarized pretensioning steel in concrete.
Creator: Dohlen, Knut Herman., Florida Atlantic University, Hartt, William H.
Abstract/Description: Pretensioned concrete members require a certain bond strength between the steel and concrete to maintain prestress force. Previous studies have indicated that when reinforcing steel in concrete is cathodically polarized, a chemical change of the cement near the steel-concrete interface occurs; and this can reduce the bond strength. In the present research experiments were conducted with concrete specimens that contained either a non-stressed seven wire steel tendon or a single strand through...
Show morePretensioned concrete members require a certain bond strength between the steel and concrete to maintain prestress force. Previous studies have indicated that when reinforcing steel in concrete is cathodically polarized, a chemical change of the cement near the steel-concrete interface occurs; and this can reduce the bond strength. In the present research experiments were conducted with concrete specimens that contained either a non-stressed seven wire steel tendon or a single strand through the longitudinal direction. The specimens were cathodically polarized with current densities ranging between 50 and 2500 mA/m^2 of steel. Upon achieving a pre-determined charge density transfer, the steel was pulled relative to the concrete until the bond was broken. Results indicate that a total charge density transfer of up to 14000 A*h/m^2 of steel, may introduce an average 16 percent decrease in ultimate bond strength. This and other data were evaluated in order to assess if cathodic protection, as utilized for corrosion control, is likely to compromise structural integrity of pretensioned concrete members and structures.
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Date Issued: 1998
PURL: http://purl.flvc.org/fcla/dt/15543
Subject Headings: Cathodic protection, Reinforced concrete--Corrosion
Format: Document (PDF)

Title: The effects of substrate, surface finish, flow rate and exposure duration on calcareous deposits.
Creator: Mantel, Katherine Elizabeth., Florida Atlantic University, Hartt, William H., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: The effect of substrate finish and composition, flow rate and exposure duration on the composition, morphology and protective properties of calcareous deposits formed during cathodic polarization of several steels in seawater has been investigated. The current density behaviour of the scale formation in conjunction with morphology and composition characteristics indicated that the substrate finish and composition did not influence the nucleation or growth of the deposit. The results strongly...
Show moreThe effect of substrate finish and composition, flow rate and exposure duration on the composition, morphology and protective properties of calcareous deposits formed during cathodic polarization of several steels in seawater has been investigated. The current density behaviour of the scale formation in conjunction with morphology and composition characteristics indicated that the substrate finish and composition did not influence the nucleation or growth of the deposit. The results strongly suggest a relationship between electrolyte velocity, current density behaviour and morphology. With increased flow and consequent higher current density requirements, results indicated a low nucleation rate of CaCO3. The current density behaviour and composition of the calcareous deposit revealed a growth progression of a Mg rich film formed in the first few minutes, followed by an increasingly uniform surface coverage by CaCO3 in the form of aragonite.
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Date Issued: 1989
PURL: http://purl.flvc.org/fcla/dt/14575
Subject Headings: Steel--Cathodic protection, Calcium carbonate
Format: Document (PDF)

Title: A critical evaluation of current demand determination methods for cathodic protection retrofits of offshore structures.
Creator: Lemieux, Edward John., Florida Atlantic University, Hartt, William H., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: Development of a baseline design protocol for cathodic protection retrofits of offshore structures is becoming an increasingly important topic in light of the large number of structures operating beyond their original cp system design life. One of the critical steps in this development is determination of the total anode mass which is required to continue sufficient cathodic protection for which structure current demand must be established. Three current demand determination methods were...
Show moreDevelopment of a baseline design protocol for cathodic protection retrofits of offshore structures is becoming an increasingly important topic in light of the large number of structures operating beyond their original cp system design life. One of the critical steps in this development is determination of the total anode mass which is required to continue sufficient cathodic protection for which structure current demand must be established. Three current demand determination methods were investigated including the Gaussian ammeter, the Potential method, which utilizes the driving potential and anode resistance in its current calculation, and the IR Drop method. To this end, three anodes were deployed at the Naval Research Laboratory, Key West, Fl., and current output determinations were made upon these. Each of the three current measurement methods was evaluated on the basis of accuracy, reliability and feasibility in field use.
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Date Issued: 1997
PURL: http://purl.flvc.org/fcla/dt/15503
Subject Headings: Cathodic protection, Offshore structures, Ocean currents
Format: Document (PDF)

Title: Steel cathodic polarization and calcareous deposit characteristics in deep seawater.
Creator: Chen, Shaowei., Florida Atlantic University, Hartt, William H., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: Field and laboratory ambient and simulated deep seawater sacrificial anode cathodic protection experiments were performed by coupling steel specimens to Al-Zn-Hg anode through an appropriately sized external resistor and thereby permitting a particular level of cathodic protection from freely corroding to overprotection to be simulated. The effects of sea current velocity, surface preparation, initial current density, temperature and hydrostatic pressure upon cathodic polarization and...
Show moreField and laboratory ambient and simulated deep seawater sacrificial anode cathodic protection experiments were performed by coupling steel specimens to Al-Zn-Hg anode through an appropriately sized external resistor and thereby permitting a particular level of cathodic protection from freely corroding to overprotection to be simulated. The effects of sea current velocity, surface preparation, initial current density, temperature and hydrostatic pressure upon cathodic polarization and characteristics of calcareous deposits were investigated in the context of slope parameter and steady-state potential and current density trend. The results revealed that a linear relationship between cathode potential and current density is applicable for design of sacrificial anode cathodic protection systems and analysis of cathodic protection survey data from existing structures both in shallow and deep waters. It was also found that for cathodically polarized steel specimens in ambient (shallow) seawater steady-state cathode potential and current density varied according to a sigmoidal trend that indicates the importance of calcareous deposits in such exposures and demonstrated the utility of rapid polarization. On the other hand, no sigmoidal trend was apparent for field and simulated deep water tests; but instead steady-state current density was constant for potential range between -0.80 and -1.05 v (Ag/AgCl). This disclosed that no particular benefit could be derived from employing rapid polarization in cold water exposures. SEM, EDX and X-ray diffraction analysis revealed that the calcareous deposits formed upon specimens exposed at 5C and ambient pressure or 8.96 MPa laboratory experiments exhibited two layer structures--an outer layer of CaCO3 as aragonite and inner layer of Mg(OH)2 as brucite. The morphology and coverage of the deposits depended on the design slope parameter (initial current density). Field testing results indicated that deposits were also composed of CaCO3 and Mg(OH)2 where the former was calcite. Because of the poor coverage of the deposits formed in the deep water condition, limited current density reduction was noted. These results suggest that a different cp design approach and strategy should be considered for deep, cold seawater compared to that commonly used in shallow water environments.
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Date Issued: 1996
PURL: http://purl.flvc.org/fcla/dt/12457
Subject Headings: Seawater corrosion, Cathodic protection, Steel--Corrosion
Format: Document (PDF)

Title: Thermodynamic analysis of the influences of temperature and pressure on deep sea cathodic protection criterion.
Creator: Wang, Weiqing., Florida Atlantic University, Hartt, William H., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: Knowledge of the reversible potential for corrosion reaction under condition of deep sea exposure and how this is influenced by parameters such as temperature and pressure is of importance to the understanding and design of deep sea cathodic protection systems, since this potential is used as the cathodic protection criterion. Also, if the polarized potential is more negative than the reversible potential of the hydrogen reaction, then hydrogen embrittlement may occur. Thermodynamic analysis...
Show moreKnowledge of the reversible potential for corrosion reaction under condition of deep sea exposure and how this is influenced by parameters such as temperature and pressure is of importance to the understanding and design of deep sea cathodic protection systems, since this potential is used as the cathodic protection criterion. Also, if the polarized potential is more negative than the reversible potential of the hydrogen reaction, then hydrogen embrittlement may occur. Thermodynamic analysis methods are used to calculate Gibbs free energy change and reversible potential of reactions involved in cathodic protection of steel for temperatures and pressures typical of deep sea. Based on the assumptions employed it is found that the reversible potential for the iron reaction becomes less negative with depth for the first 1000m and remains approximately constant beyond this.
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Date Issued: 1989
PURL: http://purl.flvc.org/fcla/dt/14515
Subject Headings: Steel--Cathodic protection, Seawater--Thermodynamics
Format: Document (PDF)

Title: Galvanic anode cathodic protection (CP) retrofit upon offshore pipelines: An analytical model for CP potential profiles.
Creator: Pierson, Patrick Robert., Florida Atlantic University, Hartt, William H., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: An analytical model for cathodic protection (CP) attenuation along a one-dimensional structure such as a pipeline is developed in terms of non-dimensional polarization and, alternately, cathode potential. The derivation is based upon the fundamental principle that (1) potential is, in fact, the potential difference across the metal/electrolyte interface, (2) an assumption of a linear potential and current density relationship, and (3) the treatment of Galvanic anodes as spherical current...
Show moreAn analytical model for cathodic protection (CP) attenuation along a one-dimensional structure such as a pipeline is developed in terms of non-dimensional polarization and, alternately, cathode potential. The derivation is based upon the fundamental principle that (1) potential is, in fact, the potential difference across the metal/electrolyte interface, (2) an assumption of a linear potential and current density relationship, and (3) the treatment of Galvanic anodes as spherical current sources. The resulting expression characterizes the distribution of protection in terms of physical design variables and electrochemical properties of the cathode. Polarization is presented graphically in terms of two parameters which are comprised of the aforementioned variables and make for a novel method of analysis. Two sample pipeline CP systems are analyzed by this method, one of which is an existing design and the other a hypothetical design used to illustrate the effect of the varying parameters. Some sample anode life calculations based upon the analytical model are performed, and a method for correcting the model for the existence of a non-spherical bracelet anode is proposed. It is concluded that electrolyte resistance (or alternately anode resistance) is of greater importance in all practical Galvanic CP attenuation calculations than is the metallic (Ohmic) resistance.
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Date Issued: 1998
PURL: http://purl.flvc.org/fcla/dt/15581
Subject Headings: Petroleum pipelines--Cathodic protection, Natural gas pipelines--Cathodic protection
Format: Document (PDF)

Title: AN ASPECT OF THE LIMITING CURRENT DENSITY ALONG THE CIRCUMFERENCE OF A STEEL CYLINDER BY THE EFFECT OF THE FLOW VELOCITY (CATHODIC PROTECTION, CIRCULAR, BOUNDARY LAYER THICKNESS).
Creator: WANG, TIEN-JEN., Florida Atlantic University, Smith, Samuel W., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: The influence of hydrodynamic parameters and limiting current density by cathodic protection on a steel cylinder in flowing water is investigated. The limiting current density variations along the circumference of a circular cylinder are determined for different flow velocities. Several methods are also used to relate the cathodic current density distribution to variations in hydrodynamic and diffusional boundary layer thickness along the circumference of the cylinder for laminar and...
Show moreThe influence of hydrodynamic parameters and limiting current density by cathodic protection on a steel cylinder in flowing water is investigated. The limiting current density variations along the circumference of a circular cylinder are determined for different flow velocities. Several methods are also used to relate the cathodic current density distribution to variations in hydrodynamic and diffusional boundary layer thickness along the circumference of the cylinder for laminar and turbulent flow regimes. a comparison of experimental current densities on a cylinder to that predicated by theory is also examined.
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Date Issued: 1986
PURL: http://purl.flvc.org/fcla/dt/14316
Subject Headings: Steel--Cathodic protection, Sea-water corrosion
Format: Document (PDF)

Title: Adhesion of calcareous deposits formed on steel surfaces under cathodic polarization.
Creator: Luo, Jiunn-Shyong, Florida Atlantic University, Hartt, William H., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: A procedure has been devised to characterize the adhesion of calcareous deposits formed upon steel in association with cathodic polarization in seawater. This involved bending the substrate in-situ and characterization of deposit debonding in terms of visual appearance, changes in the cathodic current density and the net charge transferred in association with film disruption. Specific attention has been focused upon the influence of exposure time, applied potential, flow rate, temperature,...
Show moreA procedure has been devised to characterize the adhesion of calcareous deposits formed upon steel in association with cathodic polarization in seawater. This involved bending the substrate in-situ and characterization of deposit debonding in terms of visual appearance, changes in the cathodic current density and the net charge transferred in association with film disruption. Specific attention has been focused upon the influence of exposure time, applied potential, flow rate, temperature, substrate surface finish and electrolyte type upon deposit adhesion. Presence of a Mg-rich, inner film as well as the impingement of CaCO3 particles enhanced the adhesion of calcareous deposits. Electrostatic forces, Van der Waals attraction, and chemical alteration of precipitates could be important factors contributing to deposit adhesion.
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Date Issued: 1991
PURL: http://purl.flvc.org/fcla/dt/12271
Subject Headings: Sea-water corrosion, Marine steel, Cathodic protection, Adhesives
Format: Document (PDF)

Title: Characterization of electrochemical properties of arc-sprayed zinc and zinc-aluminum alloy coatings for cathodic protection of reinforced concrete structures.
Creator: Sigonney, Yann Manuel., Florida Atlantic University, Hartt, William H., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: The present research focused on the behavior of arc sprayed zinc and zinc-aluminum coatings on concrete specimens exposed to specific relative humidity environments (100, 85, 60 and 25% RH) and with specific chloride contents (0.0, 3.0, 5.9 and 11.8 kg/m^3). All specimens experienced a decline in current output with time. Anode wastage and formation of oxidation products were mainly responsible for this lack of protection in 100 and 85% RH, whereas for 60 and 25% RH, drying of the concrete...
Show moreThe present research focused on the behavior of arc sprayed zinc and zinc-aluminum coatings on concrete specimens exposed to specific relative humidity environments (100, 85, 60 and 25% RH) and with specific chloride contents (0.0, 3.0, 5.9 and 11.8 kg/m^3). All specimens experienced a decline in current output with time. Anode wastage and formation of oxidation products were mainly responsible for this lack of protection in 100 and 85% RH, whereas for 60 and 25% RH, drying of the concrete and long-term polarization of the anode were the key factors. Validity of the DC measurements was verified with slope parameter analysis on selected specimens. In addition, Electrochemical Impedance Spectroscopy was performed on the galvanic anode and an equivalent circuit model was obtained for the zinc-concrete interface.
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Date Issued: 1999
PURL: http://purl.flvc.org/fcla/dt/15665
Subject Headings: Reinforced concrete--Corrosion, Cathodic protection, Zinc coating
Format: Document (PDF)

Title: Calcareous deposits in simulated fatigue cracks of cathodically protected steel in seawater.
Creator: Davidson, Keith Dewayne., Florida Atlantic University, Haratt, William H.
Abstract/Description: An experiment was designed to provide a simulated steel fatigue crack under cathodic protection in seawater for study. Calcareous deposits were found to form in the simulated crack at -0.800, -0.900, -1.000 and -1.100 volts (SCE) with cycle frequencies of both 0.5 and 1.0 Hertz. By X-ray and SEM analysis, calcium carbonate deposits were shown to grow in quantities sufficient to block and become compressed by this simulated crack. Increased fluid velocities from crack pumping were shown to...
Show moreAn experiment was designed to provide a simulated steel fatigue crack under cathodic protection in seawater for study. Calcareous deposits were found to form in the simulated crack at -0.800, -0.900, -1.000 and -1.100 volts (SCE) with cycle frequencies of both 0.5 and 1.0 Hertz. By X-ray and SEM analysis, calcium carbonate deposits were shown to grow in quantities sufficient to block and become compressed by this simulated crack. Increased fluid velocities from crack pumping were shown to negatively affect crystal nucleation and growth. Due to kinetic barriers to crystal growth, aragonite and brucite were determined to be the most likely deposit type; excluding calcite, dolomite and magnesite. The deposits formed at -1.000V were shown by current requirements and SEM to provide the best protection as a coating.
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Date Issued: 1988
PURL: http://purl.flvc.org/fcla/dt/14442
Subject Headings: Steel--Fatigue, Cathodic protection, Sea-water corrosion
Format: Document (PDF)

Title: Effect of cathodic protection on bond strength between prestressing steel and concrete.
Creator: Ducrocq, Luc., Florida Atlantic University, Hartt, William H.
Abstract/Description: A series of experiments was performed on prestressed concrete specimens for the purpose of studying the tendency of disbonding between the embedded steel and the concrete due to an impressed cathodic current. The procedure first involved impressing an anodic current until active potentials were recorded along the tendon length. Subsequently, cathodic polarization of the prestressed tendons was affected using a current density of 1 mA/cm^2. The strain variation of the concrete specimens was...
Show moreA series of experiments was performed on prestressed concrete specimens for the purpose of studying the tendency of disbonding between the embedded steel and the concrete due to an impressed cathodic current. The procedure first involved impressing an anodic current until active potentials were recorded along the tendon length. Subsequently, cathodic polarization of the prestressed tendons was affected using a current density of 1 mA/cm^2. The strain variation of the concrete specimens was monitored during these two procedures using gages placed on the top or bottom surface. It was found that for a current density of 1 mA/cm^2 during the 30 day monitoring period the concrete relaxed by an amount equivalent to an 80 percent loss of bond between the tendons and concrete. The implications of this with regard to cathodic protection of prestressed concrete structures and components in actual service are discussed.
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Date Issued: 1990
PURL: http://purl.flvc.org/fcla/dt/14591
Subject Headings: Prestressed steel construction, Prestressed concrete construction, Cathodic protection
Format: Document (PDF)

Title: Design approaches for asymmetrical marine pipeline cathodic protection systems.
Creator: Qian, Haijun., Florida Atlantic University, Hartt, William H., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: Marine pipeline cathodic protection systems for asymmetrical situation were systematically investigated by means of a newly proposed approach and Boundary Element Method (BEM). Potential attenuation profiles from BEM modeling indicate that far-field cathode potentials of different pipe sections approach identical values under different coating resistance and different electrolyte resistivity conditions provided anodes are separated by at least 10m and metallic resistance is negligible. A...
Show moreMarine pipeline cathodic protection systems for asymmetrical situation were systematically investigated by means of a newly proposed approach and Boundary Element Method (BEM). Potential attenuation profiles from BEM modeling indicate that far-field cathode potentials of different pipe sections approach identical values under different coating resistance and different electrolyte resistivity conditions provided anodes are separated by at least 10m and metallic resistance is negligible. A series of equations based on the Slope Parameter Method (SPM) has been modified for more extensive applicability. Several design examples have been analyzed and the results verified by BEM. Cathode potential and current demands projected by the new method are consistent with those of BEM. The inclusive equation for even anode spacing CP has been modified to include the cable parameters by combining cable resistance and the anode resistance. Current demand for existing pipelines can be determined by either of two methods. The first utilizes the inclusive equation and involves solving this for current demand based upon a known potential profile. The other is based on SPM.
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Date Issued: 2003
PURL: http://purl.flvc.org/fcla/dt/13098
Subject Headings: Underwater pipelines, Pipelines--Cathodic protection, Boundary element methods
Format: Document (PDF)

Cathodic protection (18)	+ -
Steel--Cathodic protection (6)	+ -
Sea-water corrosion (5)	+ -
Pipelines--Cathodic protection (4)	+ -
Seawater corrosion (4)	+ -

Underwater pipelines (4)	+ -
Prestressed steel construction (3)	+ -
Reinforced concrete--Corrosion (3)	+ -
Steel--Corrosion (3)	+ -
Corrosion and anti-corrosives (2)	+ -
Marine steel (2)	+ -
Offshore structures (2)	+ -
Plates, Iron and steel--Cathodic protection (2)	+ -
Prestressed concrete--Corrosion (2)	+ -
Reinforcing bars--Cathodic protection (2)	+ -
Seawater (2)	+ -
Tendons (Prestressed concrete) (2)	+ -
Adhesives (1)	+ -
Anodes (1)	+ -
Boundary element methods (1)	+ -
Calcium (1)	+ -
Calcium carbonate (1)	+ -
Calcium--Effect of temperature on (1)	+ -
Carbon steel--Corrosion (1)	+ -
Chemical oceanography (1)	+ -
Concrete piling--Corrosion (1)	+ -
Concrete--Corrosion (1)	+ -
Concrete--Deterioration (1)	+ -
Electrolytic corrosion (1)	+ -
Finite element method (1)	+ -

Florida Atlantic University (33)	+ -
College of Engineering and Computer Science (26)	+ -
Department of Ocean and Mechanical Engineering (26)	+ -
Hartt, William H. (26)	+ -
Smith, Samuel W. (4)	+ -

Luo, Jiunn-Shyong (2)	+ -
Wang, Weiqing. (2)	+ -
Bethune, Keith P. (1)	+ -
Chen, Shaowei. (1)	+ -
Davidson, Keith Dewayne. (1)	+ -
Dohlen, Knut Herman. (1)	+ -
Ducrocq, Luc. (1)	+ -
Gantiva, Nicolas. (1)	+ -
Haratt, William H. (1)	+ -
Hugus, G. Dickson, IV. (1)	+ -
Joubert, Emmanuel. (1)	+ -
KUNJAPUR, MADANA MOHAN. (1)	+ -
Kliszowski, Stanislas Henri. (1)	+ -
Le Floch, Anne. (1)	+ -
Lee, Rupert U. (1)	+ -
Lemieux, Edward John. (1)	+ -
Lysogorski, Diane K. (1)	+ -
MAO, WEI-YUN. (1)	+ -
MCCABE, KEVIN MICHAEL. (1)	+ -
Mantel, Katherine Elizabeth. (1)	+ -
NYE, TRACY LOUISE. (1)	+ -
Pangrazzi, Richard. (1)	+ -
Pierson, Patrick Robert. (1)	+ -
Poeydomenge, Arnaud. (1)	+ -
Qian, Haijun. (1)	+ -

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