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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: Non-destructive evaluation of corrosion-damaged pre-stressing steel in jacketed concrete piles.
Creator: Rapa, Martin Tymon., Florida Atlantic University, Hartt, William H., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: A study was performed for the purpose of developing a non-destructive method to evaluate corrosion damaged pre-stressing steel in jacketed concrete piles by using a cover meter. The procedure first involved taking cover meter readings with the pile jacket in place. Subsequently, a portion of the jacket was removed and tendon diameter measurements were taken. A relation for normalized tendon diameter as a function of normalized cover was determined, where normalized cover increased with a...
Show moreA study was performed for the purpose of developing a non-destructive method to evaluate corrosion damaged pre-stressing steel in jacketed concrete piles by using a cover meter. The procedure first involved taking cover meter readings with the pile jacket in place. Subsequently, a portion of the jacket was removed and tendon diameter measurements were taken. A relation for normalized tendon diameter as a function of normalized cover was determined, where normalized cover increased with a decrease in normalized tendon diameter. Finally, it is projected that the cover meter is a useful non-destructive tool to estimate the remaining tendon diameter in the inspection of jacketed, prestressed concrete piles and to this end to characterize the residual structural integrity of piles.
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Date Issued: 1998
PURL: http://purl.flvc.org/fcla/dt/15563
Subject Headings: Concrete piling, Prestressed concrete constuction--Corrosion, Prestressed steel constuction--Corrosion
Format: Document (PDF)

Title: The effects of substrate, surface finish, flow rate and exposure duration on calcareous deposits.
Creator: Mantel, Katherine Elizabeth., Florida Atlantic University, Hartt, William H., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: The effect of substrate finish and composition, flow rate and exposure duration on the composition, morphology and protective properties of calcareous deposits formed during cathodic polarization of several steels in seawater has been investigated. The current density behaviour of the scale formation in conjunction with morphology and composition characteristics indicated that the substrate finish and composition did not influence the nucleation or growth of the deposit. The results strongly...
Show moreThe effect of substrate finish and composition, flow rate and exposure duration on the composition, morphology and protective properties of calcareous deposits formed during cathodic polarization of several steels in seawater has been investigated. The current density behaviour of the scale formation in conjunction with morphology and composition characteristics indicated that the substrate finish and composition did not influence the nucleation or growth of the deposit. The results strongly suggest a relationship between electrolyte velocity, current density behaviour and morphology. With increased flow and consequent higher current density requirements, results indicated a low nucleation rate of CaCO3. The current density behaviour and composition of the calcareous deposit revealed a growth progression of a Mg rich film formed in the first few minutes, followed by an increasingly uniform surface coverage by CaCO3 in the form of aragonite.
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Date Issued: 1989
PURL: http://purl.flvc.org/fcla/dt/14575
Subject Headings: Steel--Cathodic protection, Calcium carbonate
Format: Document (PDF)

Title: A critical evaluation of current demand determination methods for cathodic protection retrofits of offshore structures.
Creator: Lemieux, Edward John., Florida Atlantic University, Hartt, William H., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: Development of a baseline design protocol for cathodic protection retrofits of offshore structures is becoming an increasingly important topic in light of the large number of structures operating beyond their original cp system design life. One of the critical steps in this development is determination of the total anode mass which is required to continue sufficient cathodic protection for which structure current demand must be established. Three current demand determination methods were...
Show moreDevelopment of a baseline design protocol for cathodic protection retrofits of offshore structures is becoming an increasingly important topic in light of the large number of structures operating beyond their original cp system design life. One of the critical steps in this development is determination of the total anode mass which is required to continue sufficient cathodic protection for which structure current demand must be established. Three current demand determination methods were investigated including the Gaussian ammeter, the Potential method, which utilizes the driving potential and anode resistance in its current calculation, and the IR Drop method. To this end, three anodes were deployed at the Naval Research Laboratory, Key West, Fl., and current output determinations were made upon these. Each of the three current measurement methods was evaluated on the basis of accuracy, reliability and feasibility in field use.
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Date Issued: 1997
PURL: http://purl.flvc.org/fcla/dt/15503
Subject Headings: Cathodic protection, Offshore structures, Ocean currents
Format: Document (PDF)

Title: Galvanic anode cathodic protection (CP) retrofit upon offshore pipelines: An analytical model for CP potential profiles.
Creator: Pierson, Patrick Robert., Florida Atlantic University, Hartt, William H., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: An analytical model for cathodic protection (CP) attenuation along a one-dimensional structure such as a pipeline is developed in terms of non-dimensional polarization and, alternately, cathode potential. The derivation is based upon the fundamental principle that (1) potential is, in fact, the potential difference across the metal/electrolyte interface, (2) an assumption of a linear potential and current density relationship, and (3) the treatment of Galvanic anodes as spherical current...
Show moreAn analytical model for cathodic protection (CP) attenuation along a one-dimensional structure such as a pipeline is developed in terms of non-dimensional polarization and, alternately, cathode potential. The derivation is based upon the fundamental principle that (1) potential is, in fact, the potential difference across the metal/electrolyte interface, (2) an assumption of a linear potential and current density relationship, and (3) the treatment of Galvanic anodes as spherical current sources. The resulting expression characterizes the distribution of protection in terms of physical design variables and electrochemical properties of the cathode. Polarization is presented graphically in terms of two parameters which are comprised of the aforementioned variables and make for a novel method of analysis. Two sample pipeline CP systems are analyzed by this method, one of which is an existing design and the other a hypothetical design used to illustrate the effect of the varying parameters. Some sample anode life calculations based upon the analytical model are performed, and a method for correcting the model for the existence of a non-spherical bracelet anode is proposed. It is concluded that electrolyte resistance (or alternately anode resistance) is of greater importance in all practical Galvanic CP attenuation calculations than is the metallic (Ohmic) resistance.
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Date Issued: 1998
PURL: http://purl.flvc.org/fcla/dt/15581
Subject Headings: Petroleum pipelines--Cathodic protection, Natural gas pipelines--Cathodic protection
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: 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: Experimental and Modeling Study of Chloride Ingress into Concrete and Reinforcement Corrosion Initiation.
Creator: Yu, Hui, Hartt, William H., Florida Atlantic University, College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: Effects of reinforcement and coarse aggregate on chloride ingression into concrete and reinforcement corrosion initiation have been studied with experimental and modeling (finite element method) analyses. Once specimens were fabricated and exposed to a chloride solution, various experimental techniques were employed to determine the effect of reinforcement and coarse aggregate on time-to-corrosion and chloride ingress and concentration at corrosion locations. Model analyses were performed to...
Show moreEffects of reinforcement and coarse aggregate on chloride ingression into concrete and reinforcement corrosion initiation have been studied with experimental and modeling (finite element method) analyses. Once specimens were fabricated and exposed to a chloride solution, various experimental techniques were employed to determine the effect of reinforcement and coarse aggregate on time-to-corrosion and chloride ingress and concentration at corrosion locations. Model analyses were performed to verify and explain the experimental results. Based upon the results, it was determined that unexpectedly higher chloride concentrations were present on the top of the rebar trace than that to the side at the same depth and an inverse concentration gradient (increasing [Cl-] with increasing depth) occurred near the top of rebars. Also, coarse aggregate volume profile in close proximity to the rebar and spatial distribution of these aggregates, in conjunction with the physical obstruction afforded by reinforcement to chloride flow, complicates concrete sampling for Cl- intended to define the critical concentration of this species to initiate corrosion. Modeling analyses that considered cover thickness, chloride threshold concentration, reinforcement size and shape, and coarse aggregate type and percolation confirmed the experimental findings. The results, at least in part, account for the relatively wide spread in chloride corrosion threshold values reported in the literature and illustrate that more consistent chloride threshold concentrations can be acquired from mortar or paste specimens than from concrete ones.
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Date Issued: 2007
PURL: http://purl.flvc.org/fau/fd/FA00012582
Subject Headings: Reinforced concrete construction--Corrosion, Chlorides--Diffusion rate, Composite reinforced concrete, Concrete--Chemical resistance
Format: Document (PDF)

Title: FATIGUE CRACK DEVELOPMENT IN CATHODICALLY POLARIZED WELDED STEEL IN SEAWATER.
Creator: WEHLING, CHRISTOPHER MARK., Florida Atlantic University, Hartt, William H., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: The fatigue crack growth behavior of welded ABS DH32 steel spec~mens cathodically polarized to -1.00 volt (Cu-CuS04) and subjected to bending fatigue of nominal stress + 69 MN/m^2 (+- 10 ksi) in seawater was investigated. Small non-propagating surface cracks with lengths up to 4.93 mm formed in the specimens. There were no s~gns of failure after 36 x 10^6 cycles when the experiment was terminated. Comparison of this test with similar freely corroding and -0.85 volt (Cu-CuS04) tests indicated...
Show moreThe fatigue crack growth behavior of welded ABS DH32 steel spec~mens cathodically polarized to -1.00 volt (Cu-CuS04) and subjected to bending fatigue of nominal stress + 69 MN/m^2 (+- 10 ksi) in seawater was investigated. Small non-propagating surface cracks with lengths up to 4.93 mm formed in the specimens. There were no s~gns of failure after 36 x 10^6 cycles when the experiment was terminated. Comparison of this test with similar freely corroding and -0.85 volt (Cu-CuS04) tests indicated that -1.00 volt (Cu-CuS04) cathodic protection is conducive to arrestment of small fatigue cracks. This suggests that modest cathodic over-protection of steel in seawater may beneficial.
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Date Issued: 1981
PURL: http://purl.flvc.org/fcla/dt/14091
Subject Headings: Steel--Fatigue
Format: Document (PDF)

Title: FATIGUE OF HIGH STRENGTH LOW-ALLOY STEELS IN NATURAL SEA WATER.
Creator: KRISHNAKUMAR, RENGAN., Florida Atlantic University, Hartt, William H., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: The fatigue response of selected high strength low alloy steels, that are under consideration for future offshore structural applications, was investigated. Freely corroding and cathodically polarized experiments were conducted under conditions relevant .to these applications. Cathodic polarization experiments involved testing of A537 Direct Quenched (A537 DQ) steel at different potentials in the -0.80 V to -1.10 V (SCE) range. The damage to freely corroding high strength steel was more than...
Show moreThe fatigue response of selected high strength low alloy steels, that are under consideration for future offshore structural applications, was investigated. Freely corroding and cathodically polarized experiments were conducted under conditions relevant .to these applications. Cathodic polarization experiments involved testing of A537 Direct Quenched (A537 DQ) steel at different potentials in the -0.80 V to -1.10 V (SCE) range. The damage to freely corroding high strength steel was more than on structural steel for calculations based on the Wirsching wide band spectrum. Polarization to -0.80 V (SCE) improved the fatigue life of A537 DQ steel over the freely corroding life. A definite conclusion with regard to the influence of different levels of cathodic polarization on the fatigue life of the steel investigated can not not be drawn based on the results from this study due to data variability.
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Date Issued: 1987
PURL: http://purl.flvc.org/fcla/dt/14374
Subject Headings: Steel--Fatigue, Seawater
Format: Document (PDF)

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

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

Title: Embrittlement susceptibility of corroded pre-stressing steel in concrete during cathodic polarization.
Creator: Poeydomenge, Arnaud., Florida Atlantic University, Hartt, William H., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: Experiments and analyses were performed to better define the limits of concern regarding hydrogen embrittlement in association with application of cathodic protection to prestressed concrete. To accomplish this, prestressed concrete specimens were locally corroded to different levels by anodic polarization and then polarized to -1.30 V SCE. A procedure of examination was developed using strain gauges to determine the level of prestrain. Relatively few brittle failures of wires resulted due,...
Show moreExperiments and analyses were performed to better define the limits of concern regarding hydrogen embrittlement in association with application of cathodic protection to prestressed concrete. To accomplish this, prestressed concrete specimens were locally corroded to different levels by anodic polarization and then polarized to -1.30 V SCE. A procedure of examination was developed using strain gauges to determine the level of prestrain. Relatively few brittle failures of wires resulted due, at least in part, to a relatively low prestrain of the pretensioned tendons. A model was developed which, coupled with data from parallel research, permitted definition of the minimum cross section for brittle failure as a function of the magnitude of prestrain and corrosion morphology of the wire. These results were tabulated in a format that can be used during field inspection to identify structural elements for which fracture could occur upon application of cathodic protection.
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Date Issued: 1997
PURL: http://purl.flvc.org/fcla/dt/15417
Subject Headings: Prestressed concrete--Corrosion, Cathodic protection, Prestressed concrete--Embrittlement, Prestressed steel construction
Format: Document (PDF)

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

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

Title: Influence of weld profile on the thickness-fatigue life relationship for welded Tee specimens.
Creator: Wang, Qingmin., Florida Atlantic University, Hartt, William H., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: An experimental investigation was performed to determine the stresses at the weld toe for a group of welded Tee specimens of API 2H Grade 42 steel with thicknesses ranging from 12.7 to 101.6 mm and weld profiles conforming to the American Welding Society Code--AWS Basic, Alternate #1 and Alternate #2. The objective was to improve the understanding of the interactive weld profile - plate thickness effect on fatigue behavior. A finite element technique was employed to compute the stress...
Show moreAn experimental investigation was performed to determine the stresses at the weld toe for a group of welded Tee specimens of API 2H Grade 42 steel with thicknesses ranging from 12.7 to 101.6 mm and weld profiles conforming to the American Welding Society Code--AWS Basic, Alternate #1 and Alternate #2. The objective was to improve the understanding of the interactive weld profile - plate thickness effect on fatigue behavior. A finite element technique was employed to compute the stress gradient along and perpendicular to the plate surface. A parametric equation of SCF as a function of weld toe radius and included angle was derived based upon the finite element analysis. The results indicate that the thickness effect can be partially reduced by using an improved weld profile which reduces the stress concentration at the weld toe.
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Date Issued: 1989
PURL: http://purl.flvc.org/fcla/dt/14563
Subject Headings: Welded joints--Fatigue
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: SPECTRUM FATIGUE ON WELDED STRUCTURAL STEEL UNDER CORROSION AND CATHODIC PROTECTION CONDITIONS.
Creator: YANG, JOE-MING., Florida Atlantic University, Hartt, William H., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: The object of this work was to investigate the fatigue performance of 25.4mm thick, butt welded ABS DH-32 steel plate under spectrum loading, which simulated the environmental conditions of the North Sea. Specimens were tested in sea water under different levels of cathodic protection. The results, including the previous freely corroding data, are discussed with regard to the effect of cyclic - frequency, loading history, weld profile and cathodic protection. This study indicated that load...
Show moreThe object of this work was to investigate the fatigue performance of 25.4mm thick, butt welded ABS DH-32 steel plate under spectrum loading, which simulated the environmental conditions of the North Sea. Specimens were tested in sea water under different levels of cathodic protection. The results, including the previous freely corroding data, are discussed with regard to the effect of cyclic - frequency, loading history, weld profile and cathodic protection. This study indicated that load interaction effects are negligible in the present experiments. However, frequency, weld geometry and cathodic protection significantly effect fatigue life.
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Date Issued: 1984
PURL: http://purl.flvc.org/fcla/dt/14207
Subject Headings: Steel, Structural--Fatigue, Steel, Structural--Testing
Format: Document (PDF)

Title: Thickness and weld profile effects upon the fatigue crack development in sea water.
Creator: Li, Yong., Florida Atlantic University, Hartt, William H., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: This research investigated the plate thickness and weld profile effects upon fatigue of structural steel in sea water. Specific attention was focused on the initiation and propagation behavior of fatigue cracks formed at the toe of different profiled welds and varied plate thicknesses. It was shown that the initiation life was reduced as the thickness increased. The improved weld profile increased the crack initiation life. Analysis of the fatigue data indicated that the Initiation Life to...
Show moreThis research investigated the plate thickness and weld profile effects upon fatigue of structural steel in sea water. Specific attention was focused on the initiation and propagation behavior of fatigue cracks formed at the toe of different profiled welds and varied plate thicknesses. It was shown that the initiation life was reduced as the thickness increased. The improved weld profile increased the crack initiation life. Analysis of the fatigue data indicated that the Initiation Life to Failure Life Ratio Ni/Nf appeared to be greater for the improved weld profile than for the AWS Basic weld profile. The improved weld profile prolonged the propagation life Np. The thickness factor influenced the propagation life Np for the improved weld profile, but the trend was uncertain for the basic weld profile.
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Date Issued: 1989
PURL: http://purl.flvc.org/fcla/dt/14532
Subject Headings: Steel, Structural--Fatigue
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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