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Title: ACOUSTIC EMISSION ASSOCIATED WITH EMBEDDED METAL CORROSION IN A CONCRETE SLAB.
Creator: MARSHALL, RICHARD MELBOURNE., Florida Atlantic University, Dunn, Stanley E., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: Measured values of attenuation with distance, amplitude distribution, and propagation velocity of acoustic emissions associated with embedded metcil corrosion induced cracking in a concrete slab are presented. An extensive review of acoustic emission signal processing techniques and theoretical background material is also included. The study points out how attenuation and propagation velocity of the acoustic emission signal affects various signal processing techniques and verifies an...
Show moreMeasured values of attenuation with distance, amplitude distribution, and propagation velocity of acoustic emissions associated with embedded metcil corrosion induced cracking in a concrete slab are presented. An extensive review of acoustic emission signal processing techniques and theoretical background material is also included. The study points out how attenuation and propagation velocity of the acoustic emission signal affects various signal processing techniques and verifies an amplitude distribution spreading rrodel. The need for further defirlition of attentuation values caused by fluid loading of the concrete surface is also discussed.
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Date Issued: 1982
PURL: http://purl.flvc.org/fcla/dt/14129
Subject Headings: Reinforced concrete--Corrosion, Acoustic emission testing
Format: Document (PDF)

Title: APPLICABILITY OF CATHODIC PROTECTION IN PREVENTION OF CORROSION DAMAGE TO STEEL TENDONS IN PRESTRESSED CONCRETE (HIGH STRENGTH STEEL, HYDROGEN EMBRITTLEMENT, BRITTLE CRACKING).
Creator: SCANNELL, WILLIAM THOMAS., Florida Atlantic University, Hartt, William H., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: A series of experiments were performed on a single tendon in a prestressed concrete slab for the purpose of studying the susceptibility of the high strength steel to brittle fracture as a result of cathodic protection. The procedure first involved impressing an anodic current until active potentials were recorded along the tendon length. Subsequently, cathodic polarization of the midsection of the tendon to -1.3 V(SCE) was effected. After a prescribed time, the tendon was removed and...
Show moreA series of experiments were performed on a single tendon in a prestressed concrete slab for the purpose of studying the susceptibility of the high strength steel to brittle fracture as a result of cathodic protection. The procedure first involved impressing an anodic current until active potentials were recorded along the tendon length. Subsequently, cathodic polarization of the midsection of the tendon to -1.3 V(SCE) was effected. After a prescribed time, the tendon was removed and sectioned into 15 ern lengths. Each segment strand was then notched and strained to failure, in three-point bending, in order to determine any effect of cathodic protection on the mechanical properties of the material. Differences in average failure loads were compared to determine if a loss of load-bearing capacity and brittle fracture occurred due to hydrogen absorption.
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Date Issued: 1986
PURL: http://purl.flvc.org/fcla/dt/14324
Subject Headings: Prestressed concrete--Testing, Steel--Corrosion
Format: Document (PDF)

Title: CHARACTERIZATION OF THE EMBRITTLEMENT TENDENCY OF A CATHODICALLY POLARIZED SUPERFERRITIC STAINLESS STEEL IN SEAWATER (HYDROGEN DAMAGE, INTERGRANULAR).
Creator: KRISHNAMURTHY, RAVI M., Florida Atlantic University, Hartt, William H., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: In order to investigate the cracking tendency of cathodically polarized SEACURE superferritic stainless steel, a series of potentiostatically controlled tests were conducted in flowing natural seawater. U-bend and tensile specimens were used to determine the threshold potential and limiting fracture stress. The microstructure was examined using a metallurgical microscope and a chemical analysis was conducted across the grain boundary. These results were then correlated to hydrogen assisted...
Show moreIn order to investigate the cracking tendency of cathodically polarized SEACURE superferritic stainless steel, a series of potentiostatically controlled tests were conducted in flowing natural seawater. U-bend and tensile specimens were used to determine the threshold potential and limiting fracture stress. The microstructure was examined using a metallurgical microscope and a chemical analysis was conducted across the grain boundary. These results were then correlated to hydrogen assisted cracking, by performing SEM and EDAX analyses on fractured U-bend and tensile samples. Finally a model was developed which explained the predominantly intergranular cracking in the static stress condition and also accommodated the transgranular failure during dynamic loading.
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Date Issued: 1986
PURL: http://purl.flvc.org/fcla/dt/14325
Subject Headings: Steel--Fracture, Sea-water corrosion
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: Chloride thresholds for initiation of corrosion of steel reinforcement in concrete.
Creator: Perks, Robert Adam., Florida Atlantic University, Hartt, William H., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: A study was performed of variables that affect the chloride threshold for corrosion of reinforcement, including pore water alkalinity, water-to-cement ratio, the use of Florida aggregate, and the addition of fly ash. To accomplish this, specimens were subjected to a periodic wet-dry ponding cycle using 15% by weight NaCl solution. Half cell potential and macrocell current measurements were taken to determine the time to corrosion. Upon active corrosion, the specimens were removed from the...
Show moreA study was performed of variables that affect the chloride threshold for corrosion of reinforcement, including pore water alkalinity, water-to-cement ratio, the use of Florida aggregate, and the addition of fly ash. To accomplish this, specimens were subjected to a periodic wet-dry ponding cycle using 15% by weight NaCl solution. Half cell potential and macrocell current measurements were taken to determine the time to corrosion. Upon active corrosion, the specimens were removed from the ponding cycle and dissected. Powder samples were collected from the concrete at the steel depth to ascertain the total chloride concentration. The determination of the pore water pH was attempted using a leaching method. To date only a portion of the specimens have displayed corrosion. The role of cement alkalinity and water-to-cement ratio in affecting corrosion resistance is reported and the results are discussed within the context of designing concrete structures for corrosion resistance.
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Date Issued: 2000
PURL: http://purl.flvc.org/fcla/dt/12721
Subject Headings: Steel--Corrosion, Reinforced concrete, Chlorides
Format: Document (PDF)

Title: Atmospheric Corrosion Study of Weathering Steel Using Sensor Technology.
Creator: Hereng, Yann, Granata, Richard D., Florida Atlantic University
Abstract/Description: This research tests the corrosion resistance of weathering steel against carbon steel exposed to dry and humid cycles during laboratory experiments. Various environments are tested and include the following parameters: chloride concentration, pH and wetting time. Corrosion values from weight loss analysis are given and studied for the same environments. X-ray diffraction characterized the formation of different oxides as a function of the environment and gave a better understanding on the...
Show moreThis research tests the corrosion resistance of weathering steel against carbon steel exposed to dry and humid cycles during laboratory experiments. Various environments are tested and include the following parameters: chloride concentration, pH and wetting time. Corrosion values from weight loss analysis are given and studied for the same environments. X-ray diffraction characterized the formation of different oxides as a function of the environment and gave a better understanding on the formation of the protective patina on the weathering steel, and validated that chamber experiments reproduce field conditions. The study is supported by the design, test and validation of an easily deployable galvanic atmospheric corrosion sensor that allowed the monitoring of the corrosion rate on an hourly basis.
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Date Issued: 2007
PURL: http://purl.flvc.org/fau/fd/FA00012526
Subject Headings: Steel, Structural--Corrosion, Reinforced concrete construction
Format: Document (PDF)

Title: DETECTION OF DETERIORATION OF REINFORCED CONCRETE BY ACOUSTIC EMISSION TECHNIQUES.
Creator: WENG, MING-YUAN., Florida Atlantic University, Dunn, Stanley E., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: In this investigation acoustic emission techniques were employed to detect deterioration of reinforced concrete. As a result of various laboratory tests, acoustic emission activity was found to be due to development of cracking only. Acoustic emission techniques were able to locate cracks in a specimen by linear location. Various acoustic emission parameters such as amplitude, signal shape and frequency were also analyzed and discussed. It was concluded that acoustic emission techniques...
Show moreIn this investigation acoustic emission techniques were employed to detect deterioration of reinforced concrete. As a result of various laboratory tests, acoustic emission activity was found to be due to development of cracking only. Acoustic emission techniques were able to locate cracks in a specimen by linear location. Various acoustic emission parameters such as amplitude, signal shape and frequency were also analyzed and discussed. It was concluded that acoustic emission techniques provided a feasible method for detection of deterioration and cracking of steel reinforced structures in laboratory studies as well as in a field environment.
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Date Issued: 1980
PURL: http://purl.flvc.org/fcla/dt/14042
Subject Headings: Acoustic emission testing, Reinforced concrete--Corrosion
Format: Document (PDF)

Title: Degradation of composite materials in a marine environment.
Creator: Pomies, Frederic., Florida Atlantic University, Carlsson, Leif A., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: Degradation of composite materials in marine environments has been investigated experimentally and with analytical and numerical methods. Basic mechanical properties, fiber volume fraction, moisture absorption curves and transverse tensile properties after water absorption were determined. Transverse fracture surfaces of dry and wet composites were inspected in a scanning electron microscope (SEM). In addition, the edge replication technique was applied. Micromechanical stress analysis of a...
Show moreDegradation of composite materials in marine environments has been investigated experimentally and with analytical and numerical methods. Basic mechanical properties, fiber volume fraction, moisture absorption curves and transverse tensile properties after water absorption were determined. Transverse fracture surfaces of dry and wet composites were inspected in a scanning electron microscope (SEM). In addition, the edge replication technique was applied. Micromechanical stress analysis of a composite subjected to mechanical, thermal and moisture loading were performed using analytical methods and finite elements. Transverse stiffness and stress levels for interfacial debonding and matrix failure were calculated and correlated with transverse stiffness and strength obtained experimentally.
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Date Issued: 1992
PURL: http://purl.flvc.org/fcla/dt/14818
Subject Headings: Composite materials, Environmental monitoring, Stress corrosion
Format: Document (PDF)

Title: Environmental cracking of reinforcing steel in saturated calcium hydroxide solutions.
Creator: Mathew, Ivan., Florida Atlantic University, Hartt, William H., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: Deterioration of reinforcing steel in concrete structures due to rebar corrosion is of national and international concern. Cathodic protection has evolved as the appropriate mitigating technique for existing structures. Another method which is being investigated is the electrochemical removal of chlorides from concrete. The current density used for this process leads to steel potentials at which hydrogen evolves. This raises concern regarding hydrogen embrittlement of reinforcing steel in...
Show moreDeterioration of reinforcing steel in concrete structures due to rebar corrosion is of national and international concern. Cathodic protection has evolved as the appropriate mitigating technique for existing structures. Another method which is being investigated is the electrochemical removal of chlorides from concrete. The current density used for this process leads to steel potentials at which hydrogen evolves. This raises concern regarding hydrogen embrittlement of reinforcing steel in concrete. For the purpose of analyzing this embrittlement tendency, a series of constant extension rate experiments was conducted in saturated calcium hydroxide solutions using notched and smooth specimens. While notched specimens did not show any effect of hydrogen embrittlement, the smooth specimens have revealed a reduction in ductility at high current densities. Experiments have shown that this loss in ductility is recoverable. Tests were also conducted on mortared smooth specimens which essentially exhibited the same trend observed as in the calcium hydroxide solution. The loss in ductility has been attributed to the enhanced void development in the presence of hydrogen during plastic deformation.
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Date Issued: 1990
PURL: http://purl.flvc.org/fcla/dt/14639
Subject Headings: Steel--Corrosion, Steel--Brittleness
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: 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)

Title: INFLUENCE BY CALCAREOUS DEPOSITS ON FATIGUE CRACK CLOSURE IN STEEL.
Creator: LEE, AI-KUO., Florida Atlantic University, Hartt, William H., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: A model for calcareous deposit induced fatigue crack closure has been previously reported based upon the criterion that the deposit thickness within the crack equals or exceeds one-half the minimum crack opening displacement. In the present paper an expanded and refined model is proposed by considering (1) compaction of calcareous deposits during the closure period of the stress cycle and (2) the relationship between R ratio and threshold stress intensity range. Compression tests upon...
Show moreA model for calcareous deposit induced fatigue crack closure has been previously reported based upon the criterion that the deposit thickness within the crack equals or exceeds one-half the minimum crack opening displacement. In the present paper an expanded and refined model is proposed by considering (1) compaction of calcareous deposits during the closure period of the stress cycle and (2) the relationship between R ratio and threshold stress intensity range. Compression tests upon calcareous films grown on steel surfaces have been performed, and these reveal the change in deposit thickness as a function of stress. The implications of these models to calcareous deposit induced fatigue crack closure are discussed in terms of mechanical and electrochemical parameters.
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Date Issued: 1986
PURL: http://purl.flvc.org/fcla/dt/14315
Subject Headings: Steel--Fatigue, Steel--Corrosion
Format: Document (PDF)

Title: Glass electrodes as a sensor for pH of porewater in concrete.
Creator: Balamuralikrishna, Radhakrishnan., Florida Atlantic University, Hartt, William H.
Abstract/Description: Experiments were developed and performed to determine if glass electrodes can be employed to accurately measure pH of porewater in concrete. An attempt was made to determine the reason for the general underestimation of the alkalinity of porewater by one or more pH units when glass electrodes are used as sensors compared to the OH- concentration obtained from titration of pore solutions expressed from hydrated cement samples. The linear response and alkaline error of glass electrodes was...
Show moreExperiments were developed and performed to determine if glass electrodes can be employed to accurately measure pH of porewater in concrete. An attempt was made to determine the reason for the general underestimation of the alkalinity of porewater by one or more pH units when glass electrodes are used as sensors compared to the OH- concentration obtained from titration of pore solutions expressed from hydrated cement samples. The linear response and alkaline error of glass electrodes was investigated. pH was measured for mortar samples cast in air as well as under CO2-free conditions. A flat-surface combination electrode was mostly employed for this purpose, but studies also involved the use of a microelectrode. The possible role played by Ca(OH)2 liberated during cement hydration in decarbonation of porewater is discussed based on experiments.
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Date Issued: 1990
PURL: http://purl.flvc.org/fcla/dt/14649
Subject Headings: Steel--Corrosion, Concrete--Chemistry
Format: Document (PDF)

Title: SIMULATED NORTH SEA SPECTRUM FATIGUE ON WELDED STEEL IN FLOWING SEA WATER.
Creator: Clark, A. M., Florida Atlantic University, Hartt, William H.
Abstract/Description: Reverse bend, uniform stress beam specimens of ABS DH-32 steel were subjected to fatigue cycles of randomly generated amplitude in a sea water environment to determine the effect of narrow band spectrum loading on cycles to failure. The loading spectrum was the C/12/20 spectrum, developed at the National Engineering Laboratory in Scotland to simulate the severe conditions of the North Sea. Some misinformation which has been published by NEL and other& regarding ~he C/12/20 spectrum is...
Show moreReverse bend, uniform stress beam specimens of ABS DH-32 steel were subjected to fatigue cycles of randomly generated amplitude in a sea water environment to determine the effect of narrow band spectrum loading on cycles to failure. The loading spectrum was the C/12/20 spectrum, developed at the National Engineering Laboratory in Scotland to simulate the severe conditions of the North Sea. Some misinformation which has been published by NEL and other& regarding ~he C/12/20 spectrum is addressed. A number ot means for presenting random amplitude cycles to failure data in the form of an SN plot are discussed. A means for taking into account fatigue test cycling rate in failure predictions is proposed, and the results of the freely corroding specimens of this investigation conform to the proposed technique. The random amplitude specimens exhibited reduced fatigue lives compared with similar specimens of an earlier constant amplitude investigation.
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Date Issued: 1983
PURL: http://purl.flvc.org/fcla/dt/14153
Subject Headings: Steel--Fatigue, Steel--Stress corrosion
Format: Document (PDF)

Title: Corrosion initiation and propagation on corrosion resistant alloys embedded in concrete by accelerated chloride transport.
Creator: Gutierrez Tellez, Francisco., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: Two duplex stainless steels rebars: UNS32304SS and UNS32101SS, were selected to investigate the corrosion initiation and propagation in reinforced concrete specimens. The investigation is divided in two phases with two different methods to accelerate the transport of chlorides through the concrete and initiate corrosion in a short period of time. After corrosion had initiated and propagated for some time; selected specimens were terminated for visual examination. On specimens selected for...
Show moreTwo duplex stainless steels rebars: UNS32304SS and UNS32101SS, were selected to investigate the corrosion initiation and propagation in reinforced concrete specimens. The investigation is divided in two phases with two different methods to accelerate the transport of chlorides through the concrete and initiate corrosion in a short period of time. After corrosion had initiated and propagated for some time; selected specimens were terminated for visual examination. On specimens selected for autopsy, the rebars in the top row showed corrosion to various degrees. Corrosion had propagated to such extent on the terminated specimens that the specimen showed cracks. Stray current might have caused accelerated corrosion on rebars where corrosion had initiated. Based on chloride concentrations measured at the rebar trace, corrosion initiated: on S32101 rebars on average at 7.9 kg/m3, and S32101 rebars on average at 6.0 kg/m3. The findings suggest that S32304 rebars corroded at a slower than S32101.
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Date Issued: 2013
PURL: http://purl.flvc.org/fcla/dt/3362380
Subject Headings: Concrete, Corrosion, Concrete construction, Reinforced concrete, Chemical resistance, Steel, Structural, Corrosion
Format: Document (PDF)

Title: Fatigue behavior of corrosion notched weathering steel samples.
Creator: Chen, Di, Granata, Richard D., Florida Atlantic University, College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: Weathering steel has been a primary construction material for bridges in the United States. Notches caused by corrosion are observed on the flange of steel I-beams. These notches reduce the cross section area of the structure and are threats to bridge safety. A606-04 Type 4 cold rolled weathering steel samples were studied in this thesis to understand the effect of notches that caused by corrosion. Weathering steel samples were in the shape of plates, which simulated flange of I-beams. The...
Show moreWeathering steel has been a primary construction material for bridges in the United States. Notches caused by corrosion are observed on the flange of steel I-beams. These notches reduce the cross section area of the structure and are threats to bridge safety. A606-04 Type 4 cold rolled weathering steel samples were studied in this thesis to understand the effect of notches that caused by corrosion. Weathering steel samples were in the shape of plates, which simulated flange of I-beams. The plate samples were notched across their surfaces by applying electrical current through an electrochemical circuit composed of an anode, a cathode and electrolyte. Sixteen samples were notched and cut into appropriate shape for fatigue testing. S-N (Stress-Number of cycles to failure) diagram established from fatigue data indicated that the fatigue strength decreased below AASHTO category B. Weibull analysis was also performed to understand the reliability distribution.
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Date Issued: 2014
PURL: http://purl.flvc.org/fau/fd/FA00004092, http://purl.flvc.org/fau/fd/FA00004092
Subject Headings: Iron and steel bridges -- Corrosion, Protective coatings -- Evaluation, Reinforced concrete construction, Steel -- Fatigue, Steel, Structural -- Corrosion
Format: Document (PDF)

Title: Accelerated corrosion of steel in dry-cast reinforced concrete pipes after initiation.
Creator: Weber, Brian W., Presuel-Moreno, Francisco, Florida Atlantic University, College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: Instrumented dry-cast reinforced concrete pipe (DC-RCP) specimens in which corrosion of the reinforcing steel had initiated were selected to accelerate the corrosion. Type C and type F DC-RCP were used. An anodic current density of various magnitudes (0.5 μA/cm2, 1 μA/cm2 and 2.5 μA/cm2) was applied during the corrosion propagation stage. The specimens were placed in high humidity and selected specimens were later covered with wet sand. Selected specimens were terminated for visual...
Show moreInstrumented dry-cast reinforced concrete pipe (DC-RCP) specimens in which corrosion of the reinforcing steel had initiated were selected to accelerate the corrosion. Type C and type F DC-RCP were used. An anodic current density of various magnitudes (0.5 μA/cm2, 1 μA/cm2 and 2.5 μA/cm2) was applied during the corrosion propagation stage. The specimens were placed in high humidity and selected specimens were later covered with wet sand. Selected specimens were terminated for visual examination and gravimetric analysis. Typically, the reinforcement potentials during the accelerated corrosion period were more negative for F specimens compared to C specimens. The C specimens experienced ~2× more corrosion than the F specimens. The accumulated corrosion products did not cause cracks. A method was developed that allows for modest corrosion acceleration during the corrosion propagation stage of DC-RCP.
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Date Issued: 2014
PURL: http://purl.flvc.org/fau/fd/FA00004233, http://purl.flvc.org/fau/fd/FA00004233
Subject Headings: Concrete -- Deterioration, Corrosion and anti corrosives, Pipelines -- Design and construction, Tubular steel structures -- Deterioration
Format: Document (PDF)

Title: Pitting potential of high performance duplex stainless steels reinforcements.
Creator: Sanchez, Erika Maria., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: A cyclic polarization procedure was designed to evaluate the pitting potentials of high performance stainless steels in synthetic concrete pore water at different chloride concentrations. Cyclic polarization scans were performed on high performance stainless steel reinforcements, S32201, S32305 and S32205. Pitting initiation was observed below the oxygen evolution potential for high chloride concentrations. S32201 and S32304 showed the presence of metastable pitting before reaching its...
Show moreA cyclic polarization procedure was designed to evaluate the pitting potentials of high performance stainless steels in synthetic concrete pore water at different chloride concentrations. Cyclic polarization scans were performed on high performance stainless steel reinforcements, S32201, S32305 and S32205. Pitting initiation was observed below the oxygen evolution potential for high chloride concentrations. S32201 and S32304 showed the presence of metastable pitting before reaching its pitting potential. Pitting resistance performance, based on cyclic polarization, was consistent with each material's respective Pitting Resistance Equivalent Number (PREN) value. For S32201 and S32304, pitting potential decreased as the chloride concentration increased, whereas S32205 did not pit at the chloride concentrations tested.
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Date Issued: 2011
PURL: http://purl.flvc.org/FAU/3334100
Subject Headings: Reinforced concrete construction, Steel, Structural, Testing, Corrosion and anti-corrosives
Format: Document (PDF)

Title: Initiation and propagation of corrosion in dry-cast reinforced concrete ring specimens.
Creator: Seo, Bongjoon, Presuel-Moreno, Francisco, Florida Atlantic University, College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: The corrosion propagation stage of D-CRP (types F and C) was tested under immersion in water, high humidity, and covered with wet sand. The half-cell potential, linear polarization test, and electrochemical impedance spectroscopy measurements were performed. Selected specimens were terminated after 300 days of exposure and visually inspected. Based on corrosion potential measurements obtained during the corrosion propagation observation, and calculated corrosion rate based on LPR measurements...
Show moreThe corrosion propagation stage of D-CRP (types F and C) was tested under immersion in water, high humidity, and covered with wet sand. The half-cell potential, linear polarization test, and electrochemical impedance spectroscopy measurements were performed. Selected specimens were terminated after 300 days of exposure and visually inspected. Based on corrosion potential measurements obtained during the corrosion propagation observation, and calculated corrosion rate based on LPR measurements: all specimens were actively corroding. Additionally, EIS-Rc values were calculated for FS, CS and CH specimens. The Rc_EIS were generally greater than Rc_LPR values. EIS spectra for CI and FI specimens usually included mass transport limitations, as these specimens were immersed. Both type of specimens immersed in water (FI and CI), appeared to have higher corrosion rate based on LPR-Rc. However, upon autopsy it was revealed that a more modest amount of corrosion occurred on the reinforcing steel of FI and CI terminated specimens.
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Date Issued: 2014
PURL: http://purl.flvc.org/fau/fd/FA00004226, http://purl.flvc.org/fau/fd/FA00004226
Subject Headings: Concrete -- Deterioration, Concrete construction, Corrosion and anti corrosives, Reinforced concrete -- Chemical resistance, Tubular steel structures -- Deterioration
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)	+ -
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