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Title: Corrosion initiation on corrosion resistant alloys via acceleration chloride transport.
Creator: Gutierrez, Francisco, Graduate College
Date Issued: 2013-04-12
PURL: http://purl.flvc.org/fcla/dt/3361305
Subject Headings: Corrosion resistant alloys, Corrosion, Corrosion and anti-corrosives--Testing
Format: Document (PDF)

Title: INFLUENCE OF DISSOLVED ORGANICS IN SEA WATER ON THE CORROSION BEHAVIOR OF SELECTED METALS.
Creator: MACDOWELL, LOUIS GARDNER, III, Florida Atlantic University
Abstract/Description: Corrosion experiments have been performed upon steel and copper in natural sea water, photo-oxidized sea water and 3.5% sodium chloride-distilled water solutions. Anodic and cathodic polarization scans were conducted, and the resulting curves were employed to characterize corrosion behavior in each of the electrolytes. While little difference as a function of electrolyte was noted for tests upon copper, variations were apparent in the case of steel. The effect of environment has been...
Show moreCorrosion experiments have been performed upon steel and copper in natural sea water, photo-oxidized sea water and 3.5% sodium chloride-distilled water solutions. Anodic and cathodic polarization scans were conducted, and the resulting curves were employed to characterize corrosion behavior in each of the electrolytes. While little difference as a function of electrolyte was noted for tests upon copper, variations were apparent in the case of steel. The effect of environment has been interpreted in terms of differences in organics adsorbed upon the metal surface from one electrolyte to the next. Significance of adsorbed organics upon corrosion rate of steel in sea water is discussed.
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Date Issued: 1979
PURL: http://purl.flvc.org/fcla/dt/13957
Subject Headings: Seawater corrosion
Format: Document (PDF)

Title: THE CORROSION OF EPOXY COATED REINFORCING STEEL.
Creator: WANG, YUN TSO, Florida Atlantic University
Abstract/Description: Tests were conducted using 10 cm. (3.93 in.) lengths of both epoxy coated and bare steel reinforcing rods in simulated concrete environments of varying pH and chloride ion levels. Polarization studies using cathodic scan techniques were used to characterize the quality of the epoxy coating. In all the environments tested, bars with more defects required larger currents at a given potential than did the bars with few defects. Corrosion potential measurements in passive environments showed...
Show moreTests were conducted using 10 cm. (3.93 in.) lengths of both epoxy coated and bare steel reinforcing rods in simulated concrete environments of varying pH and chloride ion levels. Polarization studies using cathodic scan techniques were used to characterize the quality of the epoxy coating. In all the environments tested, bars with more defects required larger currents at a given potential than did the bars with few defects. Corrosion potential measurements in passive environments showed significant fluctuations from day to day, making it difficult to use potential measurement for corrosion characterization. Galvanic couples between epoxy coated and uncoated bars indicated that galvanic currents increased as the differences in the corrosion potentials increased and also as the chloride ion content of the environment increased from 0 to 0.05 M.
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Date Issued: 1980
PURL: http://purl.flvc.org/fcla/dt/14010
Subject Headings: Concrete--Corrosion, Seawater Corrosion
Format: Document (PDF)

Title: INVESTIGATION OF CORROSION OF REINFORCING STEEL BY USING ULTRASONIC TECHNIQUES AND SPECTRAL ANALYSIS.
Creator: WANG, YUN YU, Florida Atlantic University
Abstract/Description: In this investigation an ultrasonic technique and spectral analysis were employed to detect corrosion of reinforcing steel in concrete under conditions of accelerated testing. Various properties of a transmitted ultrasonic pulse were determined, and it was concluded that the transfer function provided the most realistic possibility for detection of corrosion and cracking. The most meaningful correlations of the transfer function with corrosion and cracking events were for situations where the...
Show moreIn this investigation an ultrasonic technique and spectral analysis were employed to detect corrosion of reinforcing steel in concrete under conditions of accelerated testing. Various properties of a transmitted ultrasonic pulse were determined, and it was concluded that the transfer function provided the most realistic possibility for detection of corrosion and cracking. The most meaningful correlations of the transfer function with corrosion and cracking events were for situations where the temporal variation of the transfer function at the particular frequency was small. The appropriateness of ultrasonic parameters with regard to problems involving corrosion of reinforcing steel is discussed.
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Date Issued: 1979
PURL: http://purl.flvc.org/fcla/dt/14006
Subject Headings: Concrete--Corrosion, Seawater Corrosion
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: STRESS CORROSION CRACKING OF 7079-T651 ALUMINUM IN RESPONSE TO A CONSTANT STRESS INTENSITY.
Creator: SCOTT, DARWIN HAROLD, II., Florida Atlantic University, Hartt, William H., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: Double cantilever beam specimens of 7079-T651 aluminum were subjected to low constant stress intensities in a sea water environment to determine the stress corrosion cracking response. In addition to a constant stress intensity some specimens were subjected to controlled, constant potentials. Despite the fact that all tests were in Region I of the crack growth rate-stress intensity curve, where the former has been projected to be very dependent upon the latter, a unique relationship between...
Show moreDouble cantilever beam specimens of 7079-T651 aluminum were subjected to low constant stress intensities in a sea water environment to determine the stress corrosion cracking response. In addition to a constant stress intensity some specimens were subjected to controlled, constant potentials. Despite the fact that all tests were in Region I of the crack growth rate-stress intensity curve, where the former has been projected to be very dependent upon the latter, a unique relationship between stress intensity and crack growth rate was not always indicated. Therefore, some variable other than stress intensity is assumed to control crack growth, particularly for the first several hundred hours of exposure. The observed behavior is discussed in terms of accepted theories of stress corrosion cracking in high strength aluminum alloys, including electrochemical dissolution and hydrogen embrittlement.
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Date Issued: 1977
PURL: http://purl.flvc.org/fcla/dt/13878
Subject Headings: Stress corrosion, Aluminum--Corrosion
Format: Document (PDF)

Title: Environmental cracking susceptibility of austenitic stainless steel alloys in acidified seawater.
Creator: Poulassichidis, Antonios N., Florida Atlantic University, Lipka, Stephen M., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: The stress corrosion cracking susceptibility of austenitic stainless steels SS304L, SS316L and SS904L was studied in an acidified seawater environment by slow strain rate testing at 24, 38 and 66$\sp\circ$C. Fractographic evidence of SCC susceptibility was obtained using scanning electron microscopy. The degree of susceptibility to SCC for each alloy in these environments is discussed based on the mechanical parameters, fractography and anodic polarization behavior. The results showed that...
Show moreThe stress corrosion cracking susceptibility of austenitic stainless steels SS304L, SS316L and SS904L was studied in an acidified seawater environment by slow strain rate testing at 24, 38 and 66$\sp\circ$C. Fractographic evidence of SCC susceptibility was obtained using scanning electron microscopy. The degree of susceptibility to SCC for each alloy in these environments is discussed based on the mechanical parameters, fractography and anodic polarization behavior. The results showed that SS904L performed better than SS304L and SS316L in the aforementioned environments.
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Date Issued: 1994
PURL: http://purl.flvc.org/fcla/dt/15071
Subject Headings: Stress corrosion, Seawater corrosion, Alloys--Stress corrosion
Format: Document (PDF)

Title: Effect of strain rate and temperature on the stress corrosion cracking tendency of engineering alloys in acidified seawater.
Creator: Kundalgurki, Srivatsa G., Florida Atlantic University, Lipka, Stephen M., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: The stress corrosion cracking (SCC) tendencies of several engineering alloys were studied in an acidified seawater environment as a function of applied strain rate and electrolyte temperature. The selected alloys included austenitic stainless steels 304L, 316L, 904L and A-286 (an iron-based superalloy at two heat treatments yielding ultimate tensile strengths of 130 and 200 ksi), Inconel 718 (220 ksi ultimate tensile strength) and Hastelloys C-22 and C-276. The slow strain rate test technique...
Show moreThe stress corrosion cracking (SCC) tendencies of several engineering alloys were studied in an acidified seawater environment as a function of applied strain rate and electrolyte temperature. The selected alloys included austenitic stainless steels 304L, 316L, 904L and A-286 (an iron-based superalloy at two heat treatments yielding ultimate tensile strengths of 130 and 200 ksi), Inconel 718 (220 ksi ultimate tensile strength) and Hastelloys C-22 and C-276. The slow strain rate test technique was used to evaluate the SCC strain rate dependency of each alloy at extension rates of 4.7 x 10^-6, 4.7 x 10^-4 and 4.7 x 10^-3 mm/sec. The effect of electrolyte temperature was evaluated at 38C and 60C at a single extension rate of 4.7 x 10^-5 mm/sec. Control specimens were tested in a laboratory air environment at an extension rate of 4.7 x 10^-5 mm/sec. Various mechanical parameters of the specimens tested in the corrosive medium were compared with those of control specimens to quantify the degree of cracking. Fractographic evidence of SCC was obtained using scanning electron microscopy (SEM). An attempt was made to correlate SCC tendency with the alloy's passivation kinetics and microstructure. Atmospheric exposure testing was performed in a simulated space shuttle launch pad environment for selected alloys.
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Date Issued: 1992
PURL: http://purl.flvc.org/fcla/dt/14853
Subject Headings: Alloys--Stress corrosion, Stress corrosion, Sea-water corrosion
Format: Document (PDF)

Title: Stress corrosion cracking susceptibility of engineering alloys in acidified seawater.
Creator: Campaignolle, Xavier., Florida Atlantic University, Lipka, Stephen M.
Abstract/Description: Experiments were conducted to determine the stress corrosion cracking (SCC) susceptibility of various corrosion-resistant alloys which included: 17-4 PH, INCONEL 718 and A286. These alloys were studied for different aging (heat) treatments. Slow strain rate tests (extension rate = 4.7 x 10^-5 mm/s) were performed on each alloy in four different environments; including air and natural seawater acidified with reagent grade hydrochloric acid to a pH of 0.1, 1 and 3. During the experiments, the...
Show moreExperiments were conducted to determine the stress corrosion cracking (SCC) susceptibility of various corrosion-resistant alloys which included: 17-4 PH, INCONEL 718 and A286. These alloys were studied for different aging (heat) treatments. Slow strain rate tests (extension rate = 4.7 x 10^-5 mm/s) were performed on each alloy in four different environments; including air and natural seawater acidified with reagent grade hydrochloric acid to a pH of 0.1, 1 and 3. During the experiments, the load versus time and the open circuit potential were monitored. Various parameters such as time-to-failure, energy-to-failure, maximum or failure stress and reduction-in-area were calculated in order to determine SCC susceptibility. Fractography using SEM was conducted to confirm whether any SCC occurred and, if so, to identify its mode (intergranular or transgranular). Limited potentiodynamic studies were also completed to evaluate the passive behavior of these alloys. The results are discussed in terms of the SCC susceptibility and the nature of the cracking. An attempt was also made to correlate alloy microstructure, slow strain rate test parameters and passivation behavior with SCC susceptibility.
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Date Issued: 1991
PURL: http://purl.flvc.org/fcla/dt/14756
Subject Headings: Stress corrosion, Alloys--Stress corrosion, Metals--Stress corrosion
Format: Document (PDF)

Title: Atmospheric corrosion sensor studies in accelerated and natural environments.
Creator: Richard, Sebastien Laurent., Florida Atlantic University, Granata, Richard D., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: Tests in a cyclic chamber and in real atmospheric conditions resulted in the development of an improved corrosion coulometer sensor. First tests showed that it responded well in a reproduced environment but not satisfactorily in a real one, although it seemed to present a good correlation with the weather observations. However, these tests allowed a small time step data analysis of atmospheric corrosion and therefore an improved knowledge of this process. Also discussed are the possible ways...
Show moreTests in a cyclic chamber and in real atmospheric conditions resulted in the development of an improved corrosion coulometer sensor. First tests showed that it responded well in a reproduced environment but not satisfactorily in a real one, although it seemed to present a good correlation with the weather observations. However, these tests allowed a small time step data analysis of atmospheric corrosion and therefore an improved knowledge of this process. Also discussed are the possible ways of retrieving the corrosion coulometer data wirelessly, thus allowing a real-time analysis of atmospheric corrosion on steel structures. Ideas are proposed for improving both the sensor and the electronic package to make the system an efficient monitor of atmospheric corrosion.
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Date Issued: 2003
PURL: http://purl.flvc.org/fcla/dt/13041
Subject Headings: Corrosion and anti-corrosives, Voltameters, Detectors
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: CORROSION OF CONCRETE COVERED REINFORCING STEEL IN A MARINE ENVIRONMENT RESULTING FROM STRAY CURRENT AND GALVANIC COUPLING.
Creator: MILLER, RONALD LAWRENCE., Florida Atlantic University, Hartt, William H., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: It is recognized that reinforced concrete structures are often susceptible to stray current corrosion damage. Experiments have been performed upon a reinforced concrete bridge model in sea water, and these indicate that 0.01 percent of stray direct current in this electrolyte may enter the structure. Alternating current may also contribute to corrosion of reinforcing steel, though experimental results reveal detection to be more difficult than for direct current. Two other sources of current...
Show moreIt is recognized that reinforced concrete structures are often susceptible to stray current corrosion damage. Experiments have been performed upon a reinforced concrete bridge model in sea water, and these indicate that 0.01 percent of stray direct current in this electrolyte may enter the structure. Alternating current may also contribute to corrosion of reinforcing steel, though experimental results reveal detection to be more difficult than for direct current. Two other sources of current in reinforcing steel are from cathodic protection systems of utility attachments and from galvanic coupling of the covered steel and bare steel. Mechanisms by which the above types of current contribute to deterioration of reinforced concrete structures are discussed.
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Date Issued: 1976
PURL: http://purl.flvc.org/fcla/dt/13772
Subject Headings: Steel--Corrosion
Format: Document (PDF)

Title: Effect of Polarization on Steel Embedded in Simulated Piling Specimens Evaluated by Critical Chloride Threshold.
Creator: Tanner, Russell, Hartt, William H., Florida Atlantic University, College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: Critical chloride threshold, CT values for initiation of reinforced steel corrosion m mortar typical of Florida coastal bridge substructures were determined in laboratory tests. Previous research has reported CT values that vary by more than an order-of-magnitude, making design life estimation for structures difficult. On this basis, experiments on piling type specimens focused on [Cl-] contamination in the splash zone and coupling of this steel to a large surface area submerged anode. The...
Show moreCritical chloride threshold, CT values for initiation of reinforced steel corrosion m mortar typical of Florida coastal bridge substructures were determined in laboratory tests. Previous research has reported CT values that vary by more than an order-of-magnitude, making design life estimation for structures difficult. On this basis, experiments on piling type specimens focused on [Cl-] contamination in the splash zone and coupling of this steel to a large surface area submerged anode. The lower portion of simulated piling was immersed and the region above the waterline periodically sprayed with NaCI solution. Corrosion potential with respect to height above the waterline was monitored. A temporary depolarization method for determining as to whether or not corrosion had initiated is proposed. Chloride distribution at the reinforcement-concrete interface was determined in piling using energy dispersive x-ray analysis and related to height with respect to the waterline. Chloride threshold was related to corrosion potential.
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Date Issued: 2007
PURL: http://purl.flvc.org/fau/fd/FA00012560
Subject Headings: Reinforced concrete construction, Steel, Structural--Corrosion, Chlorides, Corrosion and anti-corrosives, Seawater corrosion
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: 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: Influences of chlorides, pH and surface films on the corrosion of reinforcing steel in alkaline solutions.
Creator: Sundaresan, Raman., Florida Atlantic University, Hartt, William H., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: The objective of this study was to determine the influences of chlorides, pH and surface films on the corrosion of reinforcing steel in alkaline solutions. Anodic and linear polarization experiments were conducted on 1018 steel specimens exposed to these environments. The results indicate that there is a threshold amount of [Cl-] beyond which passivity is compromised. The i-passive in the electrolyte of pH 12.24 was approximately 0.01 of that in the electrolyte of pH 10.13. At least a one day...
Show moreThe objective of this study was to determine the influences of chlorides, pH and surface films on the corrosion of reinforcing steel in alkaline solutions. Anodic and linear polarization experiments were conducted on 1018 steel specimens exposed to these environments. The results indicate that there is a threshold amount of [Cl-] beyond which passivity is compromised. The i-passive in the electrolyte of pH 12.24 was approximately 0.01 of that in the electrolyte of pH 10.13. At least a one day period was necessary for the effect of the excess crystals of Ca(OH)2 to be felt. Corrosion rates of specimen with a Ca(OH)2 surface film were lower than without this film. [Cl-] /[OH-] in the range 2.5 to 3.5 appeared to be the threshold for breakdown of passivity.
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Date Issued: 1989
PURL: http://purl.flvc.org/fcla/dt/14520
Subject Headings: Reinforced concrete--Corrosion, Steel--Corrosion, Corrosion and anti-corrosives
Format: Document (PDF)

Title: FREQUENCY DEPENDENCE OF SEA WATER CORROSION FATIGUE OF NOTCHED 1018 STEEL.
Creator: HENKE, THOMAS ELMER, Florida Atlantic University
Abstract/Description: Experiments were conducted to investigate frequency dependence of sea water corrosion fatigue of notched 1018 steel under constant deflection, reverse bend test conditions. Frequencies of 1850, 1200, and 600 cycles per minute (CPM) were studied. Results indicate that frequency effects are not observed at high stresses, apparently due to the mechanical damage component of the fatigue process dominating over corrosion considerations. At low stresses reduced frequency resulted in decreased...
Show moreExperiments were conducted to investigate frequency dependence of sea water corrosion fatigue of notched 1018 steel under constant deflection, reverse bend test conditions. Frequencies of 1850, 1200, and 600 cycles per minute (CPM) were studied. Results indicate that frequency effects are not observed at high stresses, apparently due to the mechanical damage component of the fatigue process dominating over corrosion considerations. At low stresses reduced frequency resulted in decreased cycles to failure. Acidification of the crack tip solution is proposed as possibly responsible for this behavior. For specimens subjected to equal stress levels in the frequency dependent region, greater cathodic protection is required to mitigate corrosion fatigue for 600 CPM specimens (-0.86 volts standard calomel electrode) (V SCE) than for 1850 CPM specimens (-079V SCE).
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Date Issued: 1975
PURL: http://purl.flvc.org/fcla/dt/13731
Subject Headings: Steel--Corrosion, Seawater
Format: Document (PDF)

Title: The role of calcium-hydroxide in the maintenance of passivity of steel.
Creator: Sohanghpurwala, Ali Akbar S., Florida Atlantic University, Hartt, William H., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: The objective of this study was to determine whether the presence of undissolved calcium hydroxide at the steel interface helped maintain or delay the breakdown of passivity under adverse conditions, such as the presence of chlorides and carbonation. Saturated calcium hydroxide solution was used as an electrolyte in the test cell, and steel specimens were exposed to a range of chloride ion concentration and carbonation. The results indicate that undissolved calcium hydroxide has an important...
Show moreThe objective of this study was to determine whether the presence of undissolved calcium hydroxide at the steel interface helped maintain or delay the breakdown of passivity under adverse conditions, such as the presence of chlorides and carbonation. Saturated calcium hydroxide solution was used as an electrolyte in the test cell, and steel specimens were exposed to a range of chloride ion concentration and carbonation. The results indicate that undissolved calcium hydroxide has an important role in the passivation of reinforcing steel. Also, the critical chloride to hydroxide ratio may be more relevant in characterizing the breakdown of passivity than the threshold value of total or soluble chloride present in the electrolyte. It was noted that in the presence of undissolved calcium hydroxide, steel remained passive for as high a chloride ion concentration as 0.54% (by weight of electrolyte).
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Date Issued: 1988
PURL: http://purl.flvc.org/fcla/dt/14429
Subject Headings: Chlorides, Steel--Corrosion
Format: Document (PDF)

Title: Effect of steel reinforcement type and surface condition on corrosion initiation in mortar.
Creator: Huang, Yirong., Florida Atlantic University, Hartt, William H.
Abstract/Description: This study employed half-cell potential (Eoc), polarization resistance (PR) and galvanic current tests to explore effects of surface condition and steel reinforcement type on corrosion initiation in mortar. A low impurity steel plate and #10 grade 60 rebar were used. Four surface conditions (as-received, atmospherically rusted, #240 SiC paper polished, and #500 SiC paper polished) were employed. Cyclic wet and dry exposure of specimens in 15% NaCl solution was conducted. Half-cell potential...
Show moreThis study employed half-cell potential (Eoc), polarization resistance (PR) and galvanic current tests to explore effects of surface condition and steel reinforcement type on corrosion initiation in mortar. A low impurity steel plate and #10 grade 60 rebar were used. Four surface conditions (as-received, atmospherically rusted, #240 SiC paper polished, and #500 SiC paper polished) were employed. Cyclic wet and dry exposure of specimens in 15% NaCl solution was conducted. Half-cell potential measurements showed that the corrosion probability of specimens with as-received and pre-rusted surfaces was lower than that of specimens with a polished surface. However, the PR and galvanic current tests indicated higher corrosion rate for specimens prepared with atmospherically rusted and as-received steels. Good agreement was found between results of the polarization resistance test and galvanic current measurements. There is a lack of correlation between half-cell potential and corrosion rate.
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Date Issued: 2003
PURL: http://purl.flvc.org/fcla/dt/13075
Subject Headings: Corrosion and anti-corrosives--Testing, Reinforced concrete--Corrosion, Mortar, Steel--Corrosion
Format: Document (PDF)

Title: Study of corrosion-induced failure mechanisms of epoxy-coated reinforcing steel.
Creator: Lee, Seung-Kyoung, Florida Atlantic University, Hartt, William H., McIntyre, Jack F., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: A study of the corrosion protection afforded by epoxy coatings on reinforcing steel was performed. To accomplish this bars were acquired from ten sources and coatings were characterized in terms of defects, thickness, solvent extraction weight loss and hardness. Testing involved exposure in various aqueous solutions at both ambient temperature and 80$\sp\circ$C and in chloride-contaminated concrete slabs under outdoor exposure. Direct pull-off adhesion testing was performed on tested and...
Show moreA study of the corrosion protection afforded by epoxy coatings on reinforcing steel was performed. To accomplish this bars were acquired from ten sources and coatings were characterized in terms of defects, thickness, solvent extraction weight loss and hardness. Testing involved exposure in various aqueous solutions at both ambient temperature and 80$\sp\circ$C and in chloride-contaminated concrete slabs under outdoor exposure. Direct pull-off adhesion testing was performed on tested and virgin epoxy coated reinforcing steels (ECRs). Electrochemical impedance spectroscopy (EIS) scans were made periodically, and a curve fitting technique was employed to analyze coating parameters. Conventional electrochemical measurements were also made, and corrosion morphology of ECR specimens was examined. It was found that the density and size of coating defects was the primary factor affecting ECR performance. The circuit analysis indicated that poorly performing defect-free coatings absorbed water and oxygen; and these species reached the coating/substrate interface and electrochemical reactions at the interface caused coating degradation. By way of contrast, the impedance response for well-performing ECR specimens showed no signs of active degradation at the interface although diffusional processes similar to those noted for poorly performing bars occurred here also. Experimental results indicated a relationship between corrosion behavior and bar source. Weight loss upon solvent extraction correlated with impedance reduction from hot water exposure. Coating defects developed during most of the tests, especially in high pH solutions containing chloride ions. ECRs with excessive coating defects, either initially present or ones which developed in service, performed poorly in every test category regardless of source. Forms of coating failure were extensive rusting at defects, blistering, wet adhesion loss, cathodic delamination, underfilm corrosion and coating cracks. These occurred sequentially or concurrently, depending on the condition of the ECR and nature of the environment.
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Date Issued: 1994
PURL: http://purl.flvc.org/fcla/dt/12389
Subject Headings: Corrosion and anti-corrosives, Epoxy coatings, Steel--Corrosion, Concrete--Corrosion
Format: Document (PDF)

FAU Theses and Dissertations (102)	+ -
FAU Graduate Student Research (2)	+ -

Steel--Corrosion (20)	+ -
Reinforced concrete--Corrosion (16)	+ -
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)	+ -
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