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Title: Volumetric changes of cement paste under exposure to the simulated corrosion products of steel and their influence on cracking susceptibility.
Creator: Bedu, Philippe., Florida Atlantic University, Hartt, William H.
Abstract/Description: Dimensional changes of thin cement paste specimens were monitored during exposure to distilled water, hydrochloric acid, alkaline and FeCl$\sb2$ solutions; and comparison was made with the experimental results obtained by other authors. Post experimental examination of reaction products formed on the specimen surface exposed to FeCl$\sb2$ was conducted using X-Ray diffraction. The data resulting from the measured dimensional changes were input to a finite element model to project the stresses...
Show moreDimensional changes of thin cement paste specimens were monitored during exposure to distilled water, hydrochloric acid, alkaline and FeCl$\sb2$ solutions; and comparison was made with the experimental results obtained by other authors. Post experimental examination of reaction products formed on the specimen surface exposed to FeCl$\sb2$ was conducted using X-Ray diffraction. The data resulting from the measured dimensional changes were input to a finite element model to project the stresses that should occur in association with localized corrosion of embedded steel and wetting of adjacent cement by aqueous FeCl$\sb2$. Implications of the findings with regard to cement and concrete cracking in association with embedded metal corrosion are discussed.
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Date Issued: 1993
PURL: http://purl.flvc.org/fcla/dt/14990
Subject Headings: Reinforced concrete--Corrosion, Reinforced concrete--Cracking, Steel--Corrosion, Volumetric analysis
Format: Document (PDF)

Title: A FATIGUE STUDY OF HY-80 STEEL IN SEA WATER.
Creator: ADAMSON, JOHNNY DALE., Florida Atlantic University, Hartt, William H.
Abstract/Description: Fatigue tests were performed at low stresss intensity ranges upon precracxed HY-80 steel specimens in air and sea water, at stress ratios of 0.1 and 0.8 with and without cathodic protection. Crack growth. was found to be higher at R = 0.8 than R = 0.1. Also, the relative positioning of fatigue crack growth rate data for freely corroding and cathodically protected specimens reversed order cs R changed from 0.1 to 0.8. Threshold stress intensity ranges were found to be higher in sea water than...
Show moreFatigue tests were performed at low stresss intensity ranges upon precracxed HY-80 steel specimens in air and sea water, at stress ratios of 0.1 and 0.8 with and without cathodic protection. Crack growth. was found to be higher at R = 0.8 than R = 0.1. Also, the relative positioning of fatigue crack growth rate data for freely corroding and cathodically protected specimens reversed order cs R changed from 0.1 to 0.8. Threshold stress intensity ranges were found to be higher in sea water than in air. A comparison of the deltaKth for HY-80 was made with. that of other steels.
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Date Issued: 1979
PURL: http://purl.flvc.org/fcla/dt/13976
Subject Headings: Steel--Fatigue
Format: Document (PDF)

Title: The role of polyethylene duct cracking in the failure of post-tensioned cables in Florida segmental bridges.
Creator: David, Florent Martin., Florida Atlantic University, Hartt, William H.
Abstract/Description: During the past several decades, segmental construction using precast sections has evolved as a preferred design and construction method for bridges. The tendons used to hold the precast sections together are comprised of cables surrounded by a plastic duct filled with grout. Cracking of the tendon's protective plastic duct has been observed in several Florida bridges. An experimental investigation was performed to characterize the material properties of the high density polyethylene ducts...
Show moreDuring the past several decades, segmental construction using precast sections has evolved as a preferred design and construction method for bridges. The tendons used to hold the precast sections together are comprised of cables surrounded by a plastic duct filled with grout. Cracking of the tendon's protective plastic duct has been observed in several Florida bridges. An experimental investigation was performed to characterize the material properties of the high density polyethylene ducts used in the past and those being specified nowadays. The degree of cure of the resin, the results of three-point bending tests for unnotched and notched specimens, the coefficient of thermal expansion, and the deformation of a tendon as a function of temperature changes were studied. The effects of the grouting pressure and the void presence in the grout were quantified and the pressurization period was shown to affect significantly the pipe strain.
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Date Issued: 2003
PURL: http://purl.flvc.org/fcla/dt/12999
Subject Headings: Pipe, Plastic--Testing, Bridges--Florida, Post-tensioned prestressed concrete construction
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: 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: Influence of pozzolanic admixtures on concrete pore water pH, chloride diffusion and chloride binding.
Creator: Charvin, Stephanie., Florida Atlantic University, Hartt, William H.
Abstract/Description: This report describes the results obtained from reinforced concrete slabs having different fly ash and silica fume content. The specimens are submitted to periodic seawater ponding. PH measurements as well as free and total chloride analyses were achieved at 1213 days in order to study the alkalinity, resistance to chloride ingress and binding properties afforded by each mix design. Water absorption experiments were also conducted at different relative humidities and in water. Pore water pH...
Show moreThis report describes the results obtained from reinforced concrete slabs having different fly ash and silica fume content. The specimens are submitted to periodic seawater ponding. PH measurements as well as free and total chloride analyses were achieved at 1213 days in order to study the alkalinity, resistance to chloride ingress and binding properties afforded by each mix design. Water absorption experiments were also conducted at different relative humidities and in water. Pore water pH was found to decrease with increasing admixture content and increasing relative humidity. The permeability to chloride ions was significantly reduced in the fly ash blends whereas most of the silica fume blends exhibited effective diffusion coefficients and chloride concentrations at the depth of steel marginally better than the controls. Both the fly ash and silica fume blends showed similar binding capacity at a given replacement ratio, the percentage of bound chloride increasing with increasing admixture content.
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Date Issued: 1999
PURL: http://purl.flvc.org/fcla/dt/15664
Subject Headings: Reinforced concrete construction--Corrosion, Concrete--Additives
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: Silicone (RTV) sealant bonded aluminum joints: An experimental study.
Creator: Antony, Melvin., Florida Atlantic University, Hartt, William H.
Abstract/Description: The performance of adhesively bonded joints in terms of strength, sealing capacity and environmental resistance is of concern to designers in many fields including the marine industry. In the present work floating roller peel tests were utilized to study the bond properties of aluminum-silicone (RTV) joints. An attempt was made to identify the factors that affect the joint strength. Experiments revealed that peel strength increased with sealant thickness and decreased at high peel rates....
Show moreThe performance of adhesively bonded joints in terms of strength, sealing capacity and environmental resistance is of concern to designers in many fields including the marine industry. In the present work floating roller peel tests were utilized to study the bond properties of aluminum-silicone (RTV) joints. An attempt was made to identify the factors that affect the joint strength. Experiments revealed that peel strength increased with sealant thickness and decreased at high peel rates. Organo-silane primer SS4044 was found to improve the weatherability and strength of the joint. Results point out that mechanical interlocking combined with chemical alteration of the substrate surface was responsible for this improved adhesion. Combinations of three different environmental parameters were studied, and it was shown that seawater was the most hostile single type and a combined exposure to seawater and UV radiation (to simulate a marine environment) proved to be the worst overall. Tests showed that relaxation was governed by sealant thickness alone and was not affected by the marine environment.
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Date Issued: 1991
PURL: http://purl.flvc.org/fcla/dt/14711
Subject Headings: Aluminum--Bonding, Sealing compounds, Strength of materials
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: Effects of cement alkalinity, exposure conditions and steel-concrete interface on the time-to-corrosion and chloride threshold for reinforcing steel in concrete.
Creator: Nam, Jingak., Florida Atlantic University, Hartt, William H., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: Effects of (1) cement alkalinity (low, normal and high), (2) exposure conditions (RH and temperature), (3) rebar surface condition (as-received versus cleaned) and (4) density and distribution of air voids at the steel-concrete interface on the chloride threshold and time-to-corrosion for reinforcing steel in concrete have been studied. Also, experiments were performed to evaluate effects of RH and temperature on the diffusion of chloride in concrete and develop a method for ex-situ pH...
Show moreEffects of (1) cement alkalinity (low, normal and high), (2) exposure conditions (RH and temperature), (3) rebar surface condition (as-received versus cleaned) and (4) density and distribution of air voids at the steel-concrete interface on the chloride threshold and time-to-corrosion for reinforcing steel in concrete have been studied. Also, experiments were performed to evaluate effects of RH and temperature on the diffusion of chloride in concrete and develop a method for ex-situ pH measurement of concrete pore water. Once specimens were fabricated and exposed to a corrosive chloride solution, various experimental techniques were employed to determine time-to-corrosion, chloride threshold, diffusion coefficient and void density along the rebar trace as well as pore water pH. Based upon the resultant data, several findings related to the above parameters have been obtained as summarized below. First, time for the corrosion initiation was longest for G109 concrete specimens with high alkalinity cement (HA). Also, chloride threshold increased with increasing time-to-corrosion and cement alkalinity. Consequently, the HA specimens exhibited the highest chloride threshold compared to low and normal alkalinity ones. Second, high temperature and temperature variations reduced time-to-corrosion of reinforcing steel in concrete since chloride diffusion was accelerated at higher temperature and possibly by temperature variations. The lowest chloride threshold values were found for outdoor exposed specimens suggesting that variation of RH or temperature (or both) facilitated rapid chloride diffusion. Third, an elevated time-to-corrosion and chloride threshold values were found for the wire brushed steel specimens compared to as-received ones. The higher ratio of [OH-]/[Fe n+] on the wire brushed steel surface compared to that of as-received case can be the possible cause because the higher ratio of this parameter enables the formation of a more protective passive film on the rebar. Fourth, voids at the steel-concrete interface facilitated passive film breakdown and onset of localized corrosion. This tendency for corrosion initiation increased in proportion to void size irrespective of specimen type. Also, [Cl -]th decreased with increasing void diameter. In addition, new ex-situ leaching method for determining concrete pore water alkalinity was developed.
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Date Issued: 2004
PURL: http://purl.flvc.org/fcla/dt/12096
Subject Headings: Reinforced concrete construction, Chlorides, Steel--Corrosion, Composite reinforced concrete
Format: Document (PDF)

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

Title: CHARACTERIZATION OF 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: Brittle propensity of chromium microalloyed and corroded prestressing steel under cathodic protection.
Creator: Stauder, Anne-Laure T., Florida Atlantic University, Hartt, William H., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: Qualification criteria for cathodic protection of pre-tensioned tendon wires in concrete were studied with regard to the risks of embrittlement due to chromium microalloying and existing corrosion damage. The selected materials included two microalloyed (with 0.23 and 0.24 w% chromium) and one non-microalloyed, high carbon prestressing steels. The slow strain rate testing technique was used to evaluate the effects of polarization to -0.90 and -1.30 VSCE upon strength and ductility of the...
Show moreQualification criteria for cathodic protection of pre-tensioned tendon wires in concrete were studied with regard to the risks of embrittlement due to chromium microalloying and existing corrosion damage. The selected materials included two microalloyed (with 0.23 and 0.24 w% chromium) and one non-microalloyed, high carbon prestressing steels. The slow strain rate testing technique was used to evaluate the effects of polarization to -0.90 and -1.30 VSCE upon strength and ductility of the steels. Fractographic analysis was performed using scanning electron microscopy. Based upon statistical analysis, an attempt was made to relate the remaining strength of the corroded wire to the extent of corrosion damage for different corrosion morphologies.
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Date Issued: 1997
PURL: http://purl.flvc.org/fcla/dt/15475
Subject Headings: Cathodic protection, Tendons (Prestressed concrete), Steel--Corrosion, Steel--Embrittlement
Format: Document (PDF)

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

Title: Cathodic polarization and protection of simulated prestressed concrete pilings in sea water.
Creator: Pangrazzi, Richard., Florida Atlantic University, Hartt, William H., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: Experiments were conducted to determine the effectiveness of cathodic polarization on simulated concrete piles containing unstressed continuous and segmented tendons exposed to sea water. Conductive rubber was used as anode material. Corrosion of the steel was enhanced by admixturing calcium chloride during concrete pouring. The specimens were cathodically polarized at constant potentials ranging from -0.72 to -1.10 V(sce). Current on and instant off potentials were monitored along the...
Show moreExperiments were conducted to determine the effectiveness of cathodic polarization on simulated concrete piles containing unstressed continuous and segmented tendons exposed to sea water. Conductive rubber was used as anode material. Corrosion of the steel was enhanced by admixturing calcium chloride during concrete pouring. The specimens were cathodically polarized at constant potentials ranging from -0.72 to -1.10 V(sce). Current on and instant off potentials were monitored along the specimen height at different water levels. The four hour potential decay criterion was used to determine if cathodic polarization was effective. Protection was achieved at locations where instant-off potentials were more negative than -0.79 V(sce). Polarization was never obtained above the anode. Also, the possibility of protecting a structure containing discontinuous steel was investigated. The results are discussed within the context of protecting actual marine pilings from corrosion.
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Date Issued: 1991
PURL: http://purl.flvc.org/fcla/dt/14699
Subject Headings: Concrete piling--Corrosion, Prestressed concrete--Corrosion, Reinforcing bars--Cathodic protection
Format: Document (PDF)

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

Title: Characterization of environmental cracking of cathodically polarized prestressing steel in a simulated concrete environment.
Creator: Narayanan, P. K., 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 environmental cracking tendency of prestressing steel tendons under cathodically polarized conditions, a series of slow strain rate tests were conducted using smooth and notched specimens in simulated concrete porewater environments. Applied potential was varied from -0.500 V to -1.500 V(SCE) at intervals of 0.200 V, and the pH range was 8.0 to 12.5. Based on the test results presented in terms of time-to-failure, reduction in crosssectional area and load at...
Show moreIn order to investigate the environmental cracking tendency of prestressing steel tendons under cathodically polarized conditions, a series of slow strain rate tests were conducted using smooth and notched specimens in simulated concrete porewater environments. Applied potential was varied from -0.500 V to -1.500 V(SCE) at intervals of 0.200 V, and the pH range was 8.0 to 12.5. Based on the test results presented in terms of time-to-failure, reduction in crosssectional area and load at failure, potential regimes for susceptibility to hydrogen embrittlement in saturated Ca(OH)2 solution were identified. SEM analyses performed for both notched and smooth specimens tested at -0.700 V and -1.300 V in saturated Ca(OH)2 solution showed that different fracture mechanisms operate at these two potentials. The cracking processes have been explained based on the test results and SEM analyses. Based upon the data obtained, the steel showed higher resistance to environmental cracking at pH 9.8 and 8.0 than for 12.5. The applicability of the results to cathodic protection of prestressed steel in concrete is discussed.
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Date Issued: 1988
PURL: http://purl.flvc.org/fcla/dt/14472
Subject Headings: Steel, High strength--Brittleness
Format: Document (PDF)

Title: CRACKING OF CONCRETE DUE TO CORROSION OF VARIOUS EMBEDDED METALS.
Creator: TURNER, DEAN HUDSON., Florida Atlantic University, Hartt, William H., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: The objective of this investigati.on was to contribute to the determination of a suitable metallic coating for steel reinforcement in concrete exposed to a marine environment and possibly to stray current. Concrete specimens embedded with steel, aluminum, cadmium, copper, molybdenum, nickel, and galvanized steel were exposed to sea water. Direct current was impressed on these to accelerate corrosion of the reinforcement so that cracking of the concrete could be observed within the time limit...
Show moreThe objective of this investigati.on was to contribute to the determination of a suitable metallic coating for steel reinforcement in concrete exposed to a marine environment and possibly to stray current. Concrete specimens embedded with steel, aluminum, cadmium, copper, molybdenum, nickel, and galvanized steel were exposed to sea water. Direct current was impressed on these to accelerate corrosion of the reinforcement so that cracking of the concrete could be observed within the time limit of the investigation. Aluminum, cadmium, copper, and nickel were found to have no beneficial effect on concrete cracking as compared to steel. In addition, no correlation between oxide-metal volume ratio and concrete time-to-cracking could be observed. It was found that corrosion of molybdenum has little or no tendency to crack concrete and its corrosion potential and active behavior approximates that of steel, indicating it may be an excellent coating.
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Date Issued: 1976
PURL: http://purl.flvc.org/fcla/dt/13820
Subject Headings: Reinforced concrete--Cracking, Underwater concrete construction, Reinforced concrete--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: 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)

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

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

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

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

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

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