View All Items

Title: SERVICEABILITY OF REINFORCED CONCRETE BEAMS SUBJECTED TO ACCELERATED CORROSION (ACOUSTIC EMISSION, DAMAGE, REMAINING STRENGTH/LIFE, TESTING).
Creator: TITUS, REJI NINAN K., Florida Atlantic University, Reddy, Dronnadula V., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: Steel reinforced concrete beams were placed in contact with seawater in a state of accelerated corrosion, for varying periods of time. Some of them were simultaneously monitored for acoustic emission and the results were analyzed to evaluate the effectiveness of acoustic emission as a non-destructive monitor of corrosion induced damage. It was shown that, in a laboratory environment, counts are good indicators of the extent of corrosion damage. A review of acoustic emission monitoring...
Show moreSteel reinforced concrete beams were placed in contact with seawater in a state of accelerated corrosion, for varying periods of time. Some of them were simultaneously monitored for acoustic emission and the results were analyzed to evaluate the effectiveness of acoustic emission as a non-destructive monitor of corrosion induced damage. It was shown that, in a laboratory environment, counts are good indicators of the extent of corrosion damage. A review of acoustic emission monitoring techniques and theoretical background is included. The concrete beams were tested for flexural strength after being corroded. Reduction in rebar section was found to have a very good correlation with da mage. An attempt was made to predict remaining life of the beams based on data obtained from the tests.
Show less
Date Issued: 1986
PURL: http://purl.flvc.org/fcla/dt/14310
Subject Headings: Reinforced concrete--Corrosion
Format: Document (PDF)

Title: Analytical evaluation of marine concrete pile repairs.
Creator: Saleh, Zaher A. Abou., Florida Atlantic University, Reddy, Dronnadula V., College of Engineering and Computer Science, Department of Civil, Environmental and Geomatics Engineering
Abstract/Description: The purpose of the thesis is to determine and compare the performance characteristics of marine piles corroded by chloride diffusion and repaired by several different methods for both uncracked and cracked concrete and to determine their structural integrity. The long-term objective is the comparison of the analytical values with those from an on-going experimental evaluation. The time for chloride concentration reach the threshold value that initiates corrosion in the reinforcement has been...
Show moreThe purpose of the thesis is to determine and compare the performance characteristics of marine piles corroded by chloride diffusion and repaired by several different methods for both uncracked and cracked concrete and to determine their structural integrity. The long-term objective is the comparison of the analytical values with those from an on-going experimental evaluation. The time for chloride concentration reach the threshold value that initiates corrosion in the reinforcement has been determined by Fick's law, extended to 2-D and 3-D chloride diffusion, for (a) uncracked concrete, and (b) for cracked concrete with the Simplified Smeared Approach (SSA). The structural integrity of the concrete circular pile is compared before and alter repair, by (a) finite element modeling using ANSYS software with the maximum deflection, and (b) beam strength analysis to find the moment capacity for cracked and ultimate conditions. The overall findings indicate the adequacy of the repair procedures.
Show less
Date Issued: 2003
PURL: http://purl.flvc.org/fcla/dt/13062
Subject Headings: Concrete piling, Reinforced concrete--Corrosion, Seawater corrosion
Format: Document (PDF)

Title: Evaluation of carbon fiber/polyetheretherketone composites exposed to marine microbial communities in laboratory media and natural seawater.
Creator: Sheetz, Andrew Douglas., Florida Atlantic University, Hartt, William H., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: This research proposed to characterize any microbial induced degradation of carbon fiber/polyetheretherketone (PEEK) composites from acid-producing bacteria (APB) and sulfate-reducing bacteria (SRB). Electrochemical impedance spectroscopy (EIS) was used to provide a measure of degradation of the composite system as a function of exposure time. In addition, mechanical testing and microscopic evaluation of the specimens were utilized to determine if changes in the EIS spectra as a function of...
Show moreThis research proposed to characterize any microbial induced degradation of carbon fiber/polyetheretherketone (PEEK) composites from acid-producing bacteria (APB) and sulfate-reducing bacteria (SRB). Electrochemical impedance spectroscopy (EIS) was used to provide a measure of degradation of the composite system as a function of exposure time. In addition, mechanical testing and microscopic evaluation of the specimens were utilized to determine if changes in the EIS spectra as a function of exposure time correlated to changes in the mechanical properties. Results from most EIS scans were consistent with a well-consolidated and undamaged composite system. Changes in the EIS response of specimens exposed to the SRB environment were not matched by a reduction in the flexural strength. Mechanical testing also indicated no reduction in the flexural strength in any of the other exposure environments. Environmental scanning electron microscopy (ESEM)/energy dispersive x-ray spectroscopy (EDS) were inconclusive, though changes in the EDS spectra were seen. No definitive degradation was seen to occur in this composite system.
Show less
Date Issued: 1998
PURL: http://purl.flvc.org/fcla/dt/15531
Subject Headings: Corrosion and anti-corrosives, Composite materials--Biodegradation
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.
Show less
Date Issued: 2007
PURL: http://purl.flvc.org/fau/fd/FA00012527
Subject Headings: Steel--Corrosion, Reinforcing bars--Corrosion, Chlorides
Format: Document (PDF)

Title: STUDY OF ELECTROCHEMISTRY MODIFICATIONS WITHIN CATHODICALLY PROTECTED FATIGUE CREVICES IN 3% SODIUM-CHLORIDE - DISTILLED WATER SOLUTION AND SEAWATER.
Creator: RAJPATHAK, SHIRISH SHRIDHAR., Florida Atlantic University, Hartt, William H., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: It is well recognized that the electrochemistry modifications within cathodically protected fatigue crevices in seawater has pronounced effect on crack growth rate. This study focuses its attention on potential distribution within simulated fatigue crevice as a function of electrolyte velocity, fatigue frequency and cathodic protection potential. Results of salt water electrolyte and seawater electrolyte are compared to bring about the effect of calcareous deposits, Finally, a mathematical...
Show moreIt is well recognized that the electrochemistry modifications within cathodically protected fatigue crevices in seawater has pronounced effect on crack growth rate. This study focuses its attention on potential distribution within simulated fatigue crevice as a function of electrolyte velocity, fatigue frequency and cathodic protection potential. Results of salt water electrolyte and seawater electrolyte are compared to bring about the effect of calcareous deposits, Finally, a mathematical model based on mass transfer laws is developed to rationalise potential distribution trends within fatigue crevice and are compared with the observed behaviour.
Show less
Date Issued: 1983
PURL: http://purl.flvc.org/fcla/dt/14151
Subject Headings: Cathodic protection, Metals--Corrosion fatigue, Sea-water corrosion
Format: Document (PDF)

Title: pH determination of concrete pore water by a leaching technique for various concrete mixtures.
Creator: Sitton, Izic., Florida Atlantic University, Hartt, William H., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: A pH determination technique of concrete pore water by means of leaching OH- ions from powdered samples was developed. This method was then evaluated in terms of sample size, extent of dilution, leaching period, the type of leaching, calcium hydroxide error, and titration scatter. Based upon variations of the above parameters it was concluded that a maximum amount of hydroxide ions was released into solution for samples with the smallest particle size within a 24 hours static leaching period....
Show moreA pH determination technique of concrete pore water by means of leaching OH- ions from powdered samples was developed. This method was then evaluated in terms of sample size, extent of dilution, leaching period, the type of leaching, calcium hydroxide error, and titration scatter. Based upon variations of the above parameters it was concluded that a maximum amount of hydroxide ions was released into solution for samples with the smallest particle size within a 24 hours static leaching period. A 50ml dilution volume proved optimum with regard to filtration and titration. Under the above circumstances calcium hydroxide dissolution did not seem to pose a significant source of error. Furthermore, repeatability of the measurements was good and titration scatter was determined to be about 0.05 pH units. This method was used to determine the pH of samples containing different amounts of fly ash or silica fume additions as well as plain cement (control) samples. A drop in OH- concentration, that is pH, was detected with increasing pozzolanic addition. The results are discussed with the context of the degree of corrosion mitigation afforded by these pozzolans.
Show less
Date Issued: 1996
PURL: http://purl.flvc.org/fcla/dt/15364
Subject Headings: Concrete--Corrosion, Seawater corrosion, Concrete--Testing, Leaching
Format: Document (PDF)

Title: Influence of direct electrical current upon specific volume of mortar in sea water.
Creator: Le Floch, Anne., Florida Atlantic University, Hartt, William H., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: Hollow, cylindrical mortar specimens of 0.4 water-cement ratio were prepared without reinforcement and exposed to flowing natural sea water for periods up to one year. Direct currents of 2, 10 and 50 mA were impressed between a mixed metal-oxide titanium substrate electrode positioned within each of these two zones, with a different electrolyte supply and exhaust for the cylinder core and exterior surface. Linear expansion of the specimens was evaluated as a function of exposure duration from...
Show moreHollow, cylindrical mortar specimens of 0.4 water-cement ratio were prepared without reinforcement and exposed to flowing natural sea water for periods up to one year. Direct currents of 2, 10 and 50 mA were impressed between a mixed metal-oxide titanium substrate electrode positioned within each of these two zones, with a different electrolyte supply and exhaust for the cylinder core and exterior surface. Linear expansion of the specimens was evaluated as a function of exposure duration from the output of embedded strain gages and from dimensional measurement of cylinder length and diameter. It was found that expansion of specimens exposed to direct current exceeded baseline ones (no current). Also, the expansion was anisotropic in that different magnitudes and trends were apparent for the diameter versus length directions. The expansion under free exposure (no current) was determined to be a function of specimen size and of the direction of measurement relative to the cast specimen face.
Show less
Date Issued: 1995
PURL: http://purl.flvc.org/fcla/dt/15214
Subject Headings: Concrete--Deterioration, Concrete--Corrosion, Seawater corrosion, Cathodic protection
Format: Document (PDF)

Title: Influence of chlorides and surface condition on pitting potential of high performance reinforcing steel.
Creator: Leroux, Virginie Edwige., Florida Atlantic University, Hartt, William H., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: In order to identify the influence of chlorides and surface finish on pitting potential of high performance reinforcing steel, cyclic polarization scans were performed on types 304, 2201 and 3Cr12 stainless steels and MMFX-II in simulated pore solution to which chloride was incrementally added. Furthermore, the surface condition was investigated with regard to the pitting potential. Pitting potential distributions versus the chloride content and surface finish were obtained. Pitting...
Show moreIn order to identify the influence of chlorides and surface finish on pitting potential of high performance reinforcing steel, cyclic polarization scans were performed on types 304, 2201 and 3Cr12 stainless steels and MMFX-II in simulated pore solution to which chloride was incrementally added. Furthermore, the surface condition was investigated with regard to the pitting potential. Pitting potential distributions versus the chloride content and surface finish were obtained. Pitting resistance was lowered as chloride was added and as the surface became rougher. Furthermore, a critical chloride to hydroxide ratio as a function of potential was determined for each material. Finally, according to the results of this study, the MMFX reinforcing steel was considered to have a corrosion performance close to that of Type 2201 stainless steel for bridge use. MMFX-II specimens with a polished surface exhibited more positive pitting potentials than did ones with an as-received finish.
Show less
Date Issued: 2004
PURL: http://purl.flvc.org/fcla/dt/13103
Subject Headings: Reinforcing bars--Corrosion, Steel, Structural--Corrosion, Chlorides
Format: Document (PDF)

Title: CORROSION MONITORING AND ANALYSIS OF REINFORCED CONCRETE: CORROSION RESISTANT ALLOYS AFTER LONG TERM EXPOSURE TO CHLORIDES.
Creator: Taylor, Redmayne, Presuel-Moreno, Francisco, Florida Atlantic University, Department of Ocean and Mechanical Engineering, College of Engineering and Computer Science
Abstract/Description: Reinforced concrete (RC) is the building block of modern architecture and industry. The failure of which is costly and dangerous. Typically made with carbon steel rebars, corrosion resistant alloys provide an alternative method of delaying failure. Stainless steels, while more expensive than carbon steels, provide excellent corrosion resistance, but less is known about the long term monitoring of corrosion activity for stainless steel than for carbon steel. This study looks at samples...
Show moreReinforced concrete (RC) is the building block of modern architecture and industry. The failure of which is costly and dangerous. Typically made with carbon steel rebars, corrosion resistant alloys provide an alternative method of delaying failure. Stainless steels, while more expensive than carbon steels, provide excellent corrosion resistance, but less is known about the long term monitoring of corrosion activity for stainless steel than for carbon steel. This study looks at samples prepared between 2005 and 2009 using 304SS, 316SS, and 2304SS rebars, as well as SMI and Stelax stainless steel clad carbon steel reinforcements embedded in three different concrete mixes. These selected samples are split into two exposure environments, inside humidity chambers within the laboratory and outdoor exposure. Measurements reported here were made monthly over the course of 250 plus days using the Galvanostatic Pulse method, Electrochemical Impedance Spectroscopy, and a Gecor 8 device. These methods were used to determine corrosion current, isolated corrosion current density, and solution resistance. Corrosion current density values calculated from measurements by the Galvanostatic Pulse and Electrochemical Impedance Spectroscopy method are too small to indicate corrosion, based on value ranges provided by Andrade. However, Gecor 8 corrosion current density values indicate low levels or moderate levels of corrosion for all samples compared to the Andrade’s value ranges. The area used by the Gecor is unknown, so it’s possible this is driving up the measured values.
Show less
Date Issued: 2023
PURL: http://purl.flvc.org/fau/fd/FA00014258
Subject Headings: Reinforced concrete, Corrosion resistant alloys, Carbon steel, Corrosion
Format: Document (PDF)

Title: Corrosion propagation of dry-cast reinforced concrete pipes after initiation.
Creator: Balasubramanian, Hariharan, Graduate College
Date Issued: 2013-04-12
PURL: http://purl.flvc.org/fcla/dt/3361269
Subject Headings: Reinforced concrete, Corrosion, Drainage pipes
Format: Document (PDF)

Title: INITIATION AND PROPAGATION OF CORROSION IN DRY-CAST REINFORCED CONCRETE PIPES WITH ENVIRONMENTAL EFFECTS.
Creator: Balasubramanian, Hariharan, Presuel-Moreno, Francisco, Florida Atlantic University, College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: This research was conducted to better understand the corrosion propagation stage on dry-cast reinforced concrete pipes (DCRCPs) while exposed to high moisture conditions and chlorides. Corrosion initiation and propagation were studied in instrumented specimens obtained from segments of dry-cast reinforced concrete pipes. All specimens were subjected to accelerated chloride transport by the application of an electric field. Corrosion of the steel wire mesh initiated after a few days to a few...
Show moreThis research was conducted to better understand the corrosion propagation stage on dry-cast reinforced concrete pipes (DCRCPs) while exposed to high moisture conditions and chlorides. Corrosion initiation and propagation were studied in instrumented specimens obtained from segments of dry-cast reinforced concrete pipes. All specimens were subjected to accelerated chloride transport by the application of an electric field. Corrosion of the steel wire mesh initiated after a few days to a few months rather than several years. The specimens were then transferred to high moisture environments (immersed in water, high humidity and/or covered with wet sand) during the corrosion propagation stage. Reinforcement potentials, linear polarization resistance (LPR) and Electrochemical Impedance Spectroscopy (EIS) measurements were carried out periodically. During the propagation stage in different exposures, reinforcement eventually reached negative potentials values (< –-0.55 Vsce), which suggest mass transfer limitations. These specimens showed no visual signs of corrosion such as cracks or corrosion products except the ones exposed to high humidity and laboratory environments; where some corrosion products have reached the concrete surface. Moreover, the apparent corrosion rate values obtained suggest high corrosion rates. No crack appearance on specimens exposed to other conditions could be explained by the porosity of the specimens; the corrosion products moved into saturated pores. It is speculated that although there might be mass transfer limitations present, the current demanded by the anode is being balanced by a larger cathode area due to macrocell effects since the high moisture conditions likely reduced the concrete resistivity and increased the throwing power. The corrected polarization resistance (Rc) was calculated by subtracting the solution resistance from the apparent polarization resistance measured. The Rc values measured over time were used to obtain the calculated mass loss (using Faraday’s Law). Most specimens were forensically analyzed and the measured mass loss compared to the calculated mass loss. The forensic examination includes the measurement of the actual corroding areas. The measured corroding areas were used to obtain corrosion current density (icorr) values. A comparison was made of the calculated corrosion current densities obtained using the linear polarization resistance method (LPR) and the extrapolation method from cyclic polarization tests. It was evident that most of the specimens’ corrosion rates were significantly high. The corrosion products filled the wet-pores inside the concrete and provide an explanation for no cracks or corrosion bleed outs being visually observed on the specimens.
Show less
Date Issued: 2019
PURL: http://purl.flvc.org/fau/fd/FA00013182
Subject Headings: Reinforced concrete, Corrosion, Environmental effects
Format: Document (PDF)

Title: Some corrosion problems associated with underwater turbines.
Creator: Miglis, Yohann., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: This thesis deals with corrosion problems of underwater turbines in marine environment. The effect of a tensile stress on the uniform corrosion rate of a metal bar is studied, and an analytical model predicting the time of service of a bar under a tensile load in a corrosive environment is proposed. Stress corrosion relationships are provided for different type of alloys, and different types of relationships. Dolinskii's and Gutman's models are studied and extended to a general order...
Show moreThis thesis deals with corrosion problems of underwater turbines in marine environment. The effect of a tensile stress on the uniform corrosion rate of a metal bar is studied, and an analytical model predicting the time of service of a bar under a tensile load in a corrosive environment is proposed. Stress corrosion relationships are provided for different type of alloys, and different types of relationships. Dolinskii's and Gutman's models are studied and extended to a general order polynomial, along with a Least Square and Spline Interpolation of the experimental data. In a second part, the effect of the passive film, delaying the initiation of the corrosion process, is studied. Finally, an algorithm predicting the time of service of a cracked bar is provided, using the stress corrosion assumption, along with a validation using experimental data.
Show less
Date Issued: 2012
PURL: http://purl.flvc.org/FAU/3342238
Subject Headings: Turbines, Stress corrosion, Testing, Computational fluid dynamics, Stress corrosion, Fracture mechanics, Measurement, Alloys, Stress corrosion, Testing, Alloys, Corrosion fatigue, Testing
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.
Show less
Date Issued: 1985
PURL: http://purl.flvc.org/fcla/dt/14264
Subject Headings: Steel--Corrosion, Reinforced concrete
Format: Document (PDF)

Title: Design of cathodic protection using BEM for components of the piilot ocean energy system.
Creator: Gantiva, Nicolas., College of Engineering and Computer Science, Florida Atlantic University, Department of Ocean and Mechanical Engineering
Abstract/Description: The Center for Ocean Energy Technology at Florida Atlantic University is developing an ocean energy turbine system to investigate the feasibility of harnessing Florida's Gulf Stream current kinetic energy and transforming it into a usable form. The turbine system has components which are prone to marine corrosion given the materials they are made of and to the harsh environment they will be exposed to. This study assumes a two-part system composed of a coating system acting as a barrier and...
Show moreThe Center for Ocean Energy Technology at Florida Atlantic University is developing an ocean energy turbine system to investigate the feasibility of harnessing Florida's Gulf Stream current kinetic energy and transforming it into a usable form. The turbine system has components which are prone to marine corrosion given the materials they are made of and to the harsh environment they will be exposed to. This study assumes a two-part system composed of a coating system acting as a barrier and sacrificial anode cathodic protection which polarizes the metal structures to a potential value where corrosion is significantly reduced. Several configurations (varying in anode quantity, size and location) were considered in order to cathodically protect the structures with various coating qualities (poor, good and excellent). These cases were modeled and simulated via Boundary Element Method software and analyzed so as to assess the most appropriate design.
Show less
Date Issued: 2010
PURL: http://purl.flvc.org/FAU/2684309
Subject Headings: Cathodic protection, Corrosion and anti-corrosives, Finite element method, Seawater corrosion, Prevention
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.
Show less
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: 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).
Show less
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: Evaluation of corrosion behavior of ion vapor deposited aluminum related coating systems.
Creator: Hang, Ling., Florida Atlantic University, McIntyre, Jack F.
Abstract/Description: Experiments were conducted to investigate the effectiveness of ion vapor deposited (IVD) aluminum as a base coat for polyurethane topcoat systems in marine environments. Three test environments were used including marine atmospheric atmosphere, quiescent filtered seawater open to laboratory air and aerated seawater. Visual observation and electrochemical impedance spectroscopy techniques were primary testing methods; other characterizations included adhesion tape test, coating thickness...
Show moreExperiments were conducted to investigate the effectiveness of ion vapor deposited (IVD) aluminum as a base coat for polyurethane topcoat systems in marine environments. Three test environments were used including marine atmospheric atmosphere, quiescent filtered seawater open to laboratory air and aerated seawater. Visual observation and electrochemical impedance spectroscopy techniques were primary testing methods; other characterizations included adhesion tape test, coating thickness measurements, holiday detection, optical microscopy, open circuit potential measurements and potentiodynamic polarization. It was found that IVD aluminum was a good candidate for replacement of environmentally sensitive coatings on AA2219-T87 and AISI 4340 steel substrates, respectively. The IVD aluminum coating provided good sacrificial protection and served as a good base for polyurethane topcoat systems. Electrochemical impedance spectroscopy was a suitable method to predict coating performance in the early stages of exposure.
Show less
Date Issued: 1993
PURL: http://purl.flvc.org/fcla/dt/14970
Subject Headings: Aluminum coating, Corrosion and anti-corrosives, Metals--Corrosion fatigue, Electrochemical analysis
Format: Document (PDF)

Title: Mathematical modeling of the pit initiation process.
Creator: Kappukattil, Lizamma Joseph., Florida Atlantic University, Lee, Rupert U., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: The potential at which pitting corrosion begins under anodic polarization is a function of the environmental parameters. Determination of this characteristic potential enables prediction of pitting susceptibility under specific environmental conditions. The pitting potentials were determined experimentally for AISI 304 stainless steel for different values of chloride ion concentration, sulphate ion concentration, temperature and solution pH. A factorial design technique was employed to study...
Show moreThe potential at which pitting corrosion begins under anodic polarization is a function of the environmental parameters. Determination of this characteristic potential enables prediction of pitting susceptibility under specific environmental conditions. The pitting potentials were determined experimentally for AISI 304 stainless steel for different values of chloride ion concentration, sulphate ion concentration, temperature and solution pH. A factorial design technique was employed to study the individual and interaction effects of parameters in order to investigate the multi-faceted nature of the pitting process. An empirical model was developed based on the result of the factorial analysis. The model emphasizes the fact that the pit nucleation process involves interrelated processes, and that the parameters behave differently with respect to each process.
Show less
Date Issued: 1989
PURL: http://purl.flvc.org/fcla/dt/14548
Subject Headings: Corrosion and anti-corrosives--Mathematical models, Metals--Corrosion fatigue--Mathematical models
Format: Document (PDF)

Title: Experimental and theoretical characterization of near-threshold fatigue crack growth for high strength steels in seawater.
Creator: Yang, Jingjun., Florida Atlantic University, Hartt, William H., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: Near-threshold fatigue crack growth rate data were generated for six high strength steels at stress ratios of 0.5 and 0.8 under different environmental conditions, which included air, freely corroding in seawater, and cathodically polarized in seawater to -0.80v, -0.95v and -1.10v (vs SCE). The influence of stress ratio, loading frequency, magnitude of cathodic polarization and initial DeltaK on fatigue crack growth behavior for these high strength steels was experimentally characterized. The...
Show moreNear-threshold fatigue crack growth rate data were generated for six high strength steels at stress ratios of 0.5 and 0.8 under different environmental conditions, which included air, freely corroding in seawater, and cathodically polarized in seawater to -0.80v, -0.95v and -1.10v (vs SCE). The influence of stress ratio, loading frequency, magnitude of cathodic polarization and initial DeltaK on fatigue crack growth behavior for these high strength steels was experimentally characterized. The results disclosed general trends of fatigue crack growth under conditions relevant to offshore structure applications and circumscribed variables that are primarily influential with regard to service performance. The rate controlling processes and cracking mechanisms of near-threshold fatigue crack growth, particularly under cathodic polarization in seawater, were also studied in conjunction with crack mouth opening displacement measurements, fractographic observation and crack profile examination. The data and observations suggest that calcareous deposit induced closure was the rate-controlling factor for near-threshold fatigue crack growth under cathodic polarization in seawater although the cracking involved a brittle failure mechanism as a result of hydrogen embrittlement. With different FCGR determining procedures which included natural K-decreasing, enhanced K-decreasing, natural K-increasing and constant DeltaK, the FCGR under cathodic polarization in seawater was found to be time-dependent and, as such, was not a unique function of DeltaK but depended upon K-history or experimental procedures. These observations were consistent with results of a theoretical analysis which involved kinetics modeling of the interaction between fatigue crack growth and calcareous deposit thickening. The model also predicted the existence of an upper limit transition DeltaK, DeltaK Upp/T, between the Paris and threshold regions and it was found that the predicted DeltaK Upp/T was in agreement with the experimental one. The basis for applying this critical parameter (DeltaK Upp/T) to offshore structure designs was addressed in conjunction with experimental results.
Show less
Date Issued: 1995
PURL: http://purl.flvc.org/fcla/dt/12410
Subject Headings: Seawater corrosion, Steel--Fatigue, Steel--Fracture, Corrosion and anti-corrosives
Format: Document (PDF)

Title: Corrosion Propagation of Reinforcing Steel Embedded in Binary and Ternary Concrete.
Creator: Hoque, Kazi Naimul, Presuel-Moreno, Francisco, Florida Atlantic University, Department of Ocean and Mechanical Engineering, College of Engineering and Computer Science
Abstract/Description: The Florida Department of Transportation (FDOT) has been using supplementary cementitious materials while constructing steel reinforced concrete marine bridge structures for over three decades. It has been found from previous studies that such additions in concrete mix makes the concrete more durable. This research was conducted to better understand the corrosion propagation stage of steel rebar embedded in high performance concrete exposed to high humidity environment. Reinforced concrete...
Show moreThe Florida Department of Transportation (FDOT) has been using supplementary cementitious materials while constructing steel reinforced concrete marine bridge structures for over three decades. It has been found from previous studies that such additions in concrete mix makes the concrete more durable. This research was conducted to better understand the corrosion propagation stage of steel rebar embedded in high performance concrete exposed to high humidity environment. Reinforced concrete samples that were made with binary mixes, and ternary mixes were considered. None of these concretes had any admixed chloride to start with. An accelerated chloride transport method was used to drive chloride ions into the concrete so that chlorides reached and exceed the chloride threshold at the rebar surface and hence the corrosion process initiated after a short period of time (within few days to few months). Once corrosion has initiated the corrosion propagation can be studied. Electrochemical measurements such as rebar potential measurements, Linear Polarization Resistance (LPR), Electrochemical Impedance Spectroscopy (EIS), and Galvanostatic Pulse (GP) measurements were taken at regular intervals (during and after the electro-migration process) to observe the corrosion propagation in each sample. During the propagation stage, reinforcement eventually reached negative potentials values (i.e., Ecorr≤ –0.200 Vsce) for all the samples. The corrected polarization resistance (Rc) was calculated by subtracting the concrete solution resistance from the apparent polarization resistance measured. The Rc values obtained from LPR and GP measurements were converted to corrosion current (as the corroding area is unknown), and these corrosion current values measured over time were used to obtain the calculated mass loss (using Faraday’s Law). A comparison was made of the calculated corrosion current obtained using the LPR and GP tests. A comparison of mass loss was also obtained from the values measured from LPR and GP tests. From the experimental results, it was observed that the corrosion current values were largely dependent on the length of solution reservoirs. For specimens cast with single rebar as well as three rebars, the most recent corrosion current values (measurements taken between July 2018 to October 2020) in general were larger for the rebars that are embedded in specimens prepared with SL mix, followed by specimens prepared with FA, T1, and T2 mixes respectively. The range of corrosion current values (most recent) were 0.8-33.8 μA for SL samples, 0.5-22.5 μA for FA samples, 0.8-14.8 μA for T1 samples, and 0.7-10.4 μA for T2 samples respectively. It was also found that the calculated mass loss values were larger for rebars that are embedded in specimens (single rebar and three rebars) prepared with SL mix, followed by specimens prepared with FA, T1, and T2 mixes respectively. The range of calculated mass loss values were 0.07-1.13 grams for SL samples, 0.06-0.62 grams for FA samples, 0.12-0.54 grams for T1 samples, and 0.06-0.40 grams for T2 samples respectively. A variety of corrosion related parameters (Ecorr, Rs, Rc, and Icorr) and calculated theoretical mass loss values observed, were due to the changing parameters such as concrete compositions, concrete cover thickness, rebar diameter, total ampere-hour applied, and reservoir size. The specimens showed no visual signs of corrosion such as cracks or corrosion products that reached the concrete surface. The actual size of the corroding sites was unknown as the specimens were not terminated for forensic analysis. The size of the corroding sites could affect how much corrosion products are required to crack the concrete. It is speculated that the corrosion products in liquid form penetrated the pore structure but did not build up enough to cause cracks. No cracks or corrosion bleed outs were observed within the monitored propagation period of approximately 1600 days.
Show less
Date Issued: 2020
PURL: http://purl.flvc.org/fau/fd/FA00013634
Subject Headings: Concrete, Concrete bridges--Corrosion, Carbon steel
Format: Document (PDF)

FAU Theses and Dissertations (103)	+ -
FAU Graduate Student Research (2)	+ -

Steel--Corrosion (20)	+ -
Reinforced concrete--Corrosion (17)	+ -
Cathodic protection (14)	+ -
Corrosion and anti-corrosives (13)	+ -
Reinforced concrete (13)	+ -

Corrosion (11)	+ -
Seawater corrosion (11)	+ -
Sea-water corrosion (10)	+ -
Chlorides (7)	+ -
Concrete (7)	+ -
Reinforced concrete construction (7)	+ -
Stress corrosion (7)	+ -
Testing (7)	+ -
Concrete--Corrosion (6)	+ -
Steel--Fatigue (6)	+ -
Reinforcing bars--Corrosion (5)	+ -
Acoustic emission testing (4)	+ -
Alloys--Stress corrosion (3)	+ -
Aluminum--Corrosion (3)	+ -
Carbon steel (3)	+ -
Composite reinforced concrete (3)	+ -
Concrete construction (3)	+ -
Concrete--Additives (3)	+ -
Quality control (3)	+ -
Reinforced concrete construction--Corrosion (3)	+ -
Reinforced concrete--Cracking (3)	+ -
Steel, Structural--Corrosion (3)	+ -
Steel--Fracture (3)	+ -
Chemical resistance (2)	+ -
Chlorides--Diffusion rate (2)	+ -

Electronic Thesis or Dissertation (103)	+ -
abstract (2)	+ -

Florida Atlantic University (93)	+ -
College of Engineering and Computer Science (73)	+ -
Department of Ocean and Mechanical Engineering (68)	+ -
Hartt, William H. (49)	+ -
Presuel-Moreno, Francisco (11)	+ -

Search In

Pages

Pages

Sort Results By:

Narrow results by:

Collection

Topical Subject

Genre

Type of Resource

Language

Creator

Format

Owner