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Title: Methods for detection and prevention of concrete cracking and spalling associated with embedded metal corrosion.
Creator: Hartt, William H., Florida Atlantic University
Date Issued: 1995-06
PURL: http://purl.flvc.org/fcla/dt/15853
Format: Document (PDF)

Title: RESPONSE OF 1018 STEEL TO CONCURRENT CYCLIC LOADING AND CATHODIC POLARIZATION IN NATURAL SEA WATER.
Creator: HOOPER, WILLIAM CLARENCE., Florida Atlantic University, Hartt, William H.
Abstract/Description: Reverse bend, constant deflection fatigue experiments were conducted in natural sea water at 1850 cycles per minute (cpm) to investigate the response of 1018 notched steel to concurrent cyclic loading and cathodic polarization. For comparison purposes S-log N curves were also determined in air and high purity argon. These indicate that the endurance limit established in sea water by cathodic polarization at -0.85 volts, Saturated Calomel Electrode (SCE), is greater than in either air or argon...
Show moreReverse bend, constant deflection fatigue experiments were conducted in natural sea water at 1850 cycles per minute (cpm) to investigate the response of 1018 notched steel to concurrent cyclic loading and cathodic polarization. For comparison purposes S-log N curves were also determined in air and high purity argon. These indicate that the endurance limit established in sea water by cathodic polarization at -0.85 volts, Saturated Calomel Electrode (SCE), is greater than in either air or argon. Two mechanisms are considered as responsible for this behavior. 1. Presence of carbonate and hydroxide deposits coupled with increased alkalinity at non-propagating crack tips. 2. Adsorbed OH- layer at non-propagating crack tips.
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Date Issued: 1976
PURL: http://purl.flvc.org/fcla/dt/13781
Subject Headings: Steel--Testing
Format: Document (PDF)

Title: THE MECHANISM OF CONCRETE CRACKING IN SEAWATER DUE TO EMBEDDED METAL CORROSION.
Creator: GRIMES, WILLIAM DARWIN., Florida Atlantic University, Hartt, William H.
Abstract/Description: Investigation of concrete-rebar interface conditions was conducted for the purpose of identifying governing parameters of the concrete cracking process in seawater. Experiments included an examination of chloride ion penetration, concrete pH as a function of metallic chloride concentration, and pH distribution within reinforced, impressed current specimens. Metal-concrete systems investigated included iron, molybdenum, cadmium, zinc, aluminum, copper, and nickel. Simplified models of the...
Show moreInvestigation of concrete-rebar interface conditions was conducted for the purpose of identifying governing parameters of the concrete cracking process in seawater. Experiments included an examination of chloride ion penetration, concrete pH as a function of metallic chloride concentration, and pH distribution within reinforced, impressed current specimens. Metal-concrete systems investigated included iron, molybdenum, cadmium, zinc, aluminum, copper, and nickel. Simplified models of the rebar corrosion process are presented in conjunction with electrochemical analysis of the projected interface chemistry. Results indicated that chlorinities greater than seawater concentration may occur as a result of potential gradients in reinforced concrete. Laboratory simulations of interface chemistry indicated that metallic and chloride ions may produce an acid pH in concrete solutions when present in sufficiently high concentrations. Heasurements of pH on the fracture face of impressed current corrosion specimens indicated localized acidic conditions can develop.
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Date Issued: 1977
PURL: http://purl.flvc.org/fcla/dt/13885
Subject Headings: Reinforced concrete--Corrosion
Format: Document (PDF)

Title: Spectrum fatigue of welded structural steel in sea water.
Creator: Clark, A. M., Qian, D., Hartt, William H., Martin, P. E., Czarnecki, M. F., Harbor Branch Oceanographic Institute
Date Issued: 1983
PURL: http://purl.flvc.org/fau/fd/FA00007432
Subject Headings: Offshore structures--Welded joints--Fatigue, Steel, Structural--Fatigue, Seawater
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 polarization response of simulated prestressed concrete piles exposed to natural sea water.
Creator: Chaix, Olivier., Florida Atlantic University, Hartt, William H.
Abstract/Description: Experiments were conducted to determine the effectiveness of localized cathodic polarization for reducing corrosion of simulated prestressed concrete piles containing admixed calcium chloride and exposed to a simulated sea water tidal cycle. The specimens contained both continuous and segmented steel tendons, the purpose of the latter being to facilitate measurement of cathodic protection current. Conductive rubber in an impressed current system was used as the anode material. The specimens...
Show moreExperiments were conducted to determine the effectiveness of localized cathodic polarization for reducing corrosion of simulated prestressed concrete piles containing admixed calcium chloride and exposed to a simulated sea water tidal cycle. The specimens contained both continuous and segmented steel tendons, the purpose of the latter being to facilitate measurement of cathodic protection current. Conductive rubber in an impressed current system was used as the anode material. The specimens were initially freely corroded and then cathodically polarized at a constant current ranging from 0.5 to 1 mA/m$\sp2$ which corresponded to potentials (current-on) which ranged from $-$0.500 to $-$1.100 V(sce) in the anode region. The magnitude of impressed current and its distribution along the embedded steel was monitored as a function of exposure time, level of polarization and water levels. Current-on and instant-off potential distribution for both the continuous and segmented tendons were also measured. The level of cathodic polarization was assessed as a function of position along the specimens by the depolarization method. The results were evaluated within the context of marine bridge substructure cathodic protection technology.
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Date Issued: 1992
PURL: http://purl.flvc.org/fcla/dt/14865
Subject Headings: Corrosion and anti-corrosives, Sea-water corrosion, Offshore structures, Reinforced concrete--Deterioration
Format: Document (PDF)

Title: CORROSION OF STEEL REINFORCEMENT IN CONCRETE: THRESHOLD CHLORIDE ION CONCENTRATION FOR CORROSION IN TYPE I PORTLAND CEMENT CONCRETE.
Creator: FUNAHASHI, MIKI., Florida Atlantic University, Hartt, William H.
Abstract/Description: Initiation of corrosion of reinforcing steel in concrete is often caused by chlorides. Using a pressurized method for the purpose of accelerating penetration of sea water into concrete, the threshold chloride ion concentration for corrosion of reinforcing steel in Type I portland cement concrete has been studied in detail. The variables that have been investigated include water-cement ratio and steel surface preparation. When corrosion was detected by electrochemical potential measurement,...
Show moreInitiation of corrosion of reinforcing steel in concrete is often caused by chlorides. Using a pressurized method for the purpose of accelerating penetration of sea water into concrete, the threshold chloride ion concentration for corrosion of reinforcing steel in Type I portland cement concrete has been studied in detail. The variables that have been investigated include water-cement ratio and steel surface preparation. When corrosion was detected by electrochemical potential measurement, the test was terminated; and chloride ion concentration was evaluated. No correlation between threshold concentration and water-cement ratio was found. With regard to surface condition, the pre-rusted steel specimen showed a tendency to corrode at a lesser chloride ion concentration than for the other preparation techniques, which were sand blasting and pretreatment in a saturated calcium hydroxide solution. The results are presented and discussed within a perspective of established concrete and corrosion technologies.
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Date Issued: 1985
PURL: http://purl.flvc.org/fcla/dt/14264
Subject Headings: Steel--Corrosion, Reinforced concrete
Format: Document (PDF)

Title: Effect of cathodic protection and cyclic frequency on corrosion fatigue of selected high strength steels in seawater.
Creator: Badve, Ashwin P., Florida Atlantic University, Hartt, William H.
Abstract/Description: Study of selected candidate steels for offshore application was undertaken to observe the effects of cathodic protection and cyclic frequency on corrosion fatigue life. Keyhole Compact Tension Fatigue experiments under constant amplitude sinusoidal loading and stress ratio of 0.5 were performed on 25.4 mm thick specimens in natural sea water and also in air upon three different steels (Y.S. 500-563 MPa). These steels represented different strengthening techniques, namely precipitation...
Show moreStudy of selected candidate steels for offshore application was undertaken to observe the effects of cathodic protection and cyclic frequency on corrosion fatigue life. Keyhole Compact Tension Fatigue experiments under constant amplitude sinusoidal loading and stress ratio of 0.5 were performed on 25.4 mm thick specimens in natural sea water and also in air upon three different steels (Y.S. 500-563 MPa). These steels represented different strengthening techniques, namely precipitation hardening, direct quenching--a thermomechanical control process (TMCP), and controlled rolling. Cathodic polarization was in the range between freely corroding and -1.10 Volts (SCE). The tests were performed at a frequency of 0.3 and 1.0 Hz. The results are presented in the S-N and potential versus cycles to initiation format. No effect of frequency (1.0-0.3 Hz) was observed at cathodic protection of -1.10 V (SCE). The steels showed an increase in fatigue life to an optimum potential, and excessive potentials were detrimental. The fatigue life in dry air was greater than in laboratory air (~50% RH).
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Date Issued: 1989
PURL: http://purl.flvc.org/fcla/dt/14494
Subject Headings: Marine steel--Fatigue, Offshore structures, Sea-water corrosion, Corrosion and anti-corrosives
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: EFFECTS OF NATURAL SEAWATER AND CATHODIC POLARIZATION OF HIGH CYCLE FATIGUE OF 5086-H34 ALUMINUM.
Creator: FLODDER, STEVEN PAUL., Florida Atlantic University, Hartt, William H.
Abstract/Description: High cycle fatigue tests were conducted using symmetrical center cracked plate specimens in air, sea water and constant potentials of -1.0V and -1.3V(SCE) at 20 Hz. (1200 cycles per minute) to determine what effect these environments had on crack growth rates, delta a/delta n (inches per cycle), of 5086-H34 aluminum when plotted against stress intensity range, delta K (Ksi root of in). Crack growth rates of 10^-8 inches per cycle were obtained which indicated that apparent threshold stress...
Show moreHigh cycle fatigue tests were conducted using symmetrical center cracked plate specimens in air, sea water and constant potentials of -1.0V and -1.3V(SCE) at 20 Hz. (1200 cycles per minute) to determine what effect these environments had on crack growth rates, delta a/delta n (inches per cycle), of 5086-H34 aluminum when plotted against stress intensity range, delta K (Ksi root of in). Crack growth rates of 10^-8 inches per cycle were obtained which indicated that apparent threshold stress intensities, delta K th, exist which are the same for air, sea water and a constant potential of -1.0V(SCE); however, under a constant potential of -1.3V(SCE) the threshold shifts to a significantly higher value. It was also observed that the different enviroments had a pronounced effect on crack growth rate only at low stress intensities. Several mechanisms are considered to explain this behavior.
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Date Issued: 1977
PURL: http://purl.flvc.org/fcla/dt/13859
Subject Headings: Aluminum--Testing, Aluminum--Fatigue
Format: Document (PDF)

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: CORROSION FATIGUE OF NOTCHED 1018 STEEL IN SEA WATER.
Creator: FLUET, JOSEPH E., JR., Florida Atlantic University, Hartt, William H.
Abstract/Description: A summary of some pertinent previous research by other authors is presented separately from the actual laboratory report. The report presents the results of air and corrosion fatigue tests which are. interpreted in terms of time to failure, crack growth history, and fracture mechanics techniques. In addition, the results of cathodic protection of corrosion fatigue tests are interpreted in terms of simple-design criteria, as well as relative to Critical Corrosion Rate Theory. One of the more...
Show moreA summary of some pertinent previous research by other authors is presented separately from the actual laboratory report. The report presents the results of air and corrosion fatigue tests which are. interpreted in terms of time to failure, crack growth history, and fracture mechanics techniques. In addition, the results of cathodic protection of corrosion fatigue tests are interpreted in terms of simple-design criteria, as well as relative to Critical Corrosion Rate Theory. One of the more significant results presented is the greater longevity of corrosion fatigue, as compared to air fatigue, notched specimens stressed within 10-15 KSI above the air endurance limit. Also, the potential required to cathodically protect such notched specimens is shown to be 50 mV lower than for comparable smooth specimens. Both phenomena are attributed in part to the lowering of crack pH to acidic levels in notched specimens.
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Date Issued: 1976
PURL: http://purl.flvc.org/fcla/dt/13768
Subject Headings: Steel--Fatigue, Steel--Corrosion, Steel--Fracture, Notched bar testing
Format: Document (PDF)

Title: Evaluation of Corrosion Resistant Ferric-Alloys in Chloride Contaminated Concrete.
Creator: Himiob, Rodrigo J., Hartt, William H., Florida Atlantic University
Abstract/Description: The penetration of chloride ions through concrete can compromise the integrity of a structure. The chloride concentration, [Cl-], at which the corrosion process initiates is termed the critical chloride concentration or chloride threshold, [Cl-]th. One of the purposes of this research was to determine the [Cl-]th for various reinforcing alloys. Furthermore, the time-to-corrosion (TIC) was measured to determine the time at which bars become active. Both parameters, [Cl-]th and TTC, were found...
Show moreThe penetration of chloride ions through concrete can compromise the integrity of a structure. The chloride concentration, [Cl-], at which the corrosion process initiates is termed the critical chloride concentration or chloride threshold, [Cl-]th. One of the purposes of this research was to determine the [Cl-]th for various reinforcing alloys. Furthermore, the time-to-corrosion (TIC) was measured to determine the time at which bars become active. Both parameters, [Cl-]th and TTC, were found to be distributed; therefore, statistical analyses were performed to forecast the probability of activity. A new experimental procedure was introduced to increase the TTC data set by electrically isolating the top bars as they became active. The research also compared the [Cl-] for core samples with those values obtained from along the top rebar trace. In general, this analysis demonstrated that core sample [Cr] was lower than at the rebar-trace.
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Date Issued: 2007
PURL: http://purl.flvc.org/fau/fd/FA00012527
Subject Headings: Steel--Corrosion, Reinforcing bars--Corrosion, Chlorides
Format: Document (PDF)

Title: INTERGRANULAR CORROSION OF 5086-H34 ALUMINUM.
Creator: DUNN, MICHAEL JOSEPH., Florida Atlantic University, Hartt, William H.
Abstract/Description: Experiments were carried out in order to better characterize the intergranular corrosion process of 5086-H34 aluminum in sea water. Specimens were exposed at a constant potential in the range -0.75VSCE
Show moreExperiments were carried out in order to better characterize the intergranular corrosion process of 5086-H34 aluminum in sea water. Specimens were exposed at a constant potential in the range -0.75VSCE < corr < -0.83 Volts Saturated Calomel Electrode (VSCE). As a result, it was found that for a potential noble to -0.79VSCE intergranular corrosion indeed occurs. Under the same conditions 5052-H34 shows no intergranular attack. Since the major difference between these alloys is beta phase percent and distribution, this implies a minimum of this phase is required for intergranular corrosion to occur. Measurements of pH within simulated occluded cells were made in an attempt to obtain reasons for the observed -0.79VSCE threshold. The results of this did not point to any particular course which would explain this potential.
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Date Issued: 1975
PURL: http://purl.flvc.org/fcla/dt/13752, http://purl.flvc.org/fau/fd/FADT13752
Subject Headings: Aluminum--Corrosion
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: Obstruction of chloride diffusion in concrete by embedded reinforcing bars.
Creator: Cros, Pascal., Florida Atlantic University, Hartt, William H.
Abstract/Description: A study was performed of the effect of reinforcing bars on chloride diffusion into concrete. These bars act as obstacles to chloride movement, and this obstruction allows the chloride concentration to build-up faster along the top of the reinforcing bar than elsewhere. As a consequence, the critical chloride threshold to initiate corrosion of the steel is reached sooner than otherwise expected. This research was performed using two different methods. First, chloride analyses were performed on...
Show moreA study was performed of the effect of reinforcing bars on chloride diffusion into concrete. These bars act as obstacles to chloride movement, and this obstruction allows the chloride concentration to build-up faster along the top of the reinforcing bar than elsewhere. As a consequence, the critical chloride threshold to initiate corrosion of the steel is reached sooner than otherwise expected. This research was performed using two different methods. First, chloride analyses were performed on chloride exposed concrete blocks by taking cores in the concrete and drillings along the trace of the top bars. Second, concrete blocks models were analyzed by finite element analysis and the effect of the obstruction by the bar quantified. The role of the reinforcing bar in the chloride diffusional flow is discussed considering these two methods.
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Date Issued: 2005
PURL: http://purl.flvc.org/fcla/dt/13239
Subject Headings: Reinforcing bars--Corrosion, Reinforced concrete construction--Corrosion, Concrete--Additives, Chlorides--Diffusion rate
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: A STUDY OF STRESS CORROSION CRACKING IN 7079-T651 ALUMINUM.
Creator: FINNEGAN, JOHN EDMUND., Florida Atlantic University, Hartt, William H.
Abstract/Description: This study investigated the stress corrosion cracking behavior of aluminum alloy 7079 - T651 in two corrosive environments, sea water and a 3% NaCl-distilled water solution. Self stressing, double cantilever beam specimens were employed; and these were stressed at various levels, exposed in one of the two test environments and crack extension monitored as a function of time. Equations for the plane strain stress intensity factor (K1) were compared and evaluated, with respect to stress...
Show moreThis study investigated the stress corrosion cracking behavior of aluminum alloy 7079 - T651 in two corrosive environments, sea water and a 3% NaCl-distilled water solution. Self stressing, double cantilever beam specimens were employed; and these were stressed at various levels, exposed in one of the two test environments and crack extension monitored as a function of time. Equations for the plane strain stress intensity factor (K1) were compared and evaluated, with respect to stress intensities calculated from compliance measurements. Results suggest that stress intensity is not the only important variable controlling crack growth rate and a time dependent cracking mechanism may govern a portion of crack growth.
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Date Issued: 1975
PURL: http://purl.flvc.org/fcla/dt/13730
Subject Headings: Aluminum--Corrosion, Stress corrosion
Format: Document (PDF)

Title: STUDY OF THE WIDE-BAND SPECTRUM FATIGUE ON WELDED OFFSHORE STRUCTURES.
Creator: CHU, ZIN-HON., Florida Atlantic University, Hartt, William H.
Abstract/Description: In the present research butt welded ABS DH-32 steel specimens were fatigue tested under freely corroding and cathodic protection conditions by a time-series simulated wide-band spectra of a North Sea wave climate. Previous research pertaining to the probabilistic features of wave dynamics, wave force models, Markov-Chain sea state evolution and time-series simulation of wide-band spectra are addressed as a background review. The resulting freely corroding data are discussed on the basis of...
Show moreIn the present research butt welded ABS DH-32 steel specimens were fatigue tested under freely corroding and cathodic protection conditions by a time-series simulated wide-band spectra of a North Sea wave climate. Previous research pertaining to the probabilistic features of wave dynamics, wave force models, Markov-Chain sea state evolution and time-series simulation of wide-band spectra are addressed as a background review. The resulting freely corroding data are discussed on the basis of the SN plot which developed from the previous investigations at FAU. Calculation of the damage of failed specimens by employing the "Equivalent Narrow-Band Approach" resulted in excellent agreement with the linear damage summation assumption.
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Date Issued: 1985
PURL: http://purl.flvc.org/fcla/dt/14266
Subject Headings: Steel--Fatigue, Steel--Corrosion
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)

FAU Theses and Dissertations (80)	+ -
HBOI Faculty Contributions (1)	+ -
Florida Atlantic University Patents (1)	+ -

Steel--Corrosion (19)	+ -
Cathodic protection (15)	+ -
Steel--Fatigue (9)	+ -
Corrosion and anti-corrosives (8)	+ -
Reinforced concrete--Corrosion (8)	+ -

Chlorides (6)	+ -
Sea-water corrosion (6)	+ -
Seawater corrosion (6)	+ -
Offshore structures (4)	+ -
Pipelines--Cathodic protection (4)	+ -
Seawater (4)	+ -
Steel--Cathodic protection (4)	+ -
Underwater pipelines (4)	+ -
Aluminum--Corrosion (3)	+ -
Concrete--Corrosion (3)	+ -
Prestressed steel construction (3)	+ -
Reinforced concrete construction--Corrosion (3)	+ -
Reinforcing bars--Corrosion (3)	+ -
Steel, Structural--Fatigue (3)	+ -
Steel--Fracture (3)	+ -
Bridges--Florida (2)	+ -
Chlorides--Diffusion rate (2)	+ -
Composite reinforced concrete (2)	+ -
Concrete--Additives (2)	+ -
Concrete--Deterioration (2)	+ -
Marine steel (2)	+ -
Post-tensioned prestressed concrete construction (2)	+ -
Prestressed concrete--Corrosion (2)	+ -
Reinforced concrete (2)	+ -
Reinforced concrete construction (2)	+ -

Electronic Thesis or Dissertation (80)	+ -
article (1)	+ -
patent (1)	+ -

Hartt, William H. (82)	+ -
Florida Atlantic University (81)	+ -
College of Engineering and Computer Science (54)	+ -
Department of Ocean and Mechanical Engineering (54)	+ -
Clark, A. M. (2)	+ -

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