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Title: Effects of High Alkalinity Cements on the Control of Alkali-Silica Reaction for Reinforced Concrete.
Creator: Suarez, Jorge Alejandro, Hartt, William H., Florida Atlantic University, College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: In previous research, cements with high alkali content (EqA 1.0-1.2 percent) extended the corrosion initiation time of reinforcing steel in concrete. During this study, laboratory tests were performed to determine the suitability of high alkalinity cements to improve concrete durability without modifying physical properties and to control the risk of alkali-aggregate reaction (AAR). A mix design for the FOOT-Class V concrete served as base material for this study. On a cubic meter basis the...
Show moreIn previous research, cements with high alkali content (EqA 1.0-1.2 percent) extended the corrosion initiation time of reinforcing steel in concrete. During this study, laboratory tests were performed to determine the suitability of high alkalinity cements to improve concrete durability without modifying physical properties and to control the risk of alkali-aggregate reaction (AAR). A mix design for the FOOT-Class V concrete served as base material for this study. On a cubic meter basis the cementitious material in this concrete included 363 kg of Type l/ll Portland cement and 83 kg of Class F fly ash. The water-to-cementitious material ratio of the concrete was 0.40. The fine aggregate used in the experimental concretes was quartz sand from a Florida source with no history of alkali-silica reactivity (ASR) susceptibility. A number of cement alkali contents were prepared by different additions of sodium hydroxide to the concrete mix (3.42 - 4.57 kglm\ in some cases, and by using different cements in others. Thus, effects on concrete susceptibility to ASR, electrical resistivity, and strength were studied. Pore water alkalinity was measured by ex-situ leaching and pore water extraction methods. It was concluded that leaching procedures were not appropriate to determine concrete pore water alkalinity in the presence of fly ash. Results suggested that it is feasible to use high alkali cement without the risk of ASR or the loss of strength for two of the seven coarse aggregates studied, given that supplementary cementitious materials and lithium nitrate admixtures are utilized. Criteria for qualification of a concrete as being ASR resistant was based on dimensional stability (less than 0.01% average specimen length change) and the absence of cracking over the one and two year exposure periods according to ASTM Cl293. Based on the fundamentals of the electric double layer theory, the incidence of bivalent cations adjacent to the surface of cement hydrates and reactive silica particles was proposed to provide an explanation for the effects of alkali addition on the electrical resistivity of concrete and the source of the expansive nature of the ASR gel.
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Date Issued: 2006
PURL: http://purl.flvc.org/fau/fd/FA00012578
Subject Headings: Reinforced con crete construction, Concrete--Deterioration, Alkali-aggregate reactions, Silica
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: Effect of Polarization on Steel Embedded in Simulated Piling Specimens Evaluated by Critical Chloride Threshold.
Creator: Tanner, Russell, Hartt, William H., Florida Atlantic University, College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: Critical chloride threshold, CT values for initiation of reinforced steel corrosion m mortar typical of Florida coastal bridge substructures were determined in laboratory tests. Previous research has reported CT values that vary by more than an order-of-magnitude, making design life estimation for structures difficult. On this basis, experiments on piling type specimens focused on [Cl-] contamination in the splash zone and coupling of this steel to a large surface area submerged anode. The...
Show moreCritical chloride threshold, CT values for initiation of reinforced steel corrosion m mortar typical of Florida coastal bridge substructures were determined in laboratory tests. Previous research has reported CT values that vary by more than an order-of-magnitude, making design life estimation for structures difficult. On this basis, experiments on piling type specimens focused on [Cl-] contamination in the splash zone and coupling of this steel to a large surface area submerged anode. The lower portion of simulated piling was immersed and the region above the waterline periodically sprayed with NaCI solution. Corrosion potential with respect to height above the waterline was monitored. A temporary depolarization method for determining as to whether or not corrosion had initiated is proposed. Chloride distribution at the reinforcement-concrete interface was determined in piling using energy dispersive x-ray analysis and related to height with respect to the waterline. Chloride threshold was related to corrosion potential.
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Date Issued: 2007
PURL: http://purl.flvc.org/fau/fd/FA00012560
Subject Headings: Reinforced concrete construction, Steel, Structural--Corrosion, Chlorides, Corrosion and anti-corrosives, Seawater corrosion
Format: Document (PDF)

Title: Fatigue crack growth rate of short cracks for high strength steels in sea water.
Creator: Kim, Kijoon., Florida Atlantic University, Hartt, William H., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: Experiments have been performed which determined the fatigue crack growth rate (FCGR) of short cracks (a > 0.1mm) for five high strength steels (yield stress 370-570 MPa) in air and in natural seawater with and without cathodic protection. Attention was focused upon Regions I and Il of the classical FCGR-stress intensity range(Delta K) curve with particular consideration of the near-threshold behavior for short cracks. Single edge notch (SEN) three-point bend specimens and a direct current...
Show moreExperiments have been performed which determined the fatigue crack growth rate (FCGR) of short cracks (a > 0.1mm) for five high strength steels (yield stress 370-570 MPa) in air and in natural seawater with and without cathodic protection. Attention was focused upon Regions I and Il of the classical FCGR-stress intensity range(Delta K) curve with particular consideration of the near-threshold behavior for short cracks. Single edge notch (SEN) three-point bend specimens and a direct current potential drop (DCPD) crack monitoring system were employed, and test parameters simulated offshore structure conditions. The results indicated enhanced FCGR for short cracks compared to macrocracks by 3-20 times in air and 2-6 in seawater free-corroding(FC). Also, the Delta Kth for short cracks was apparently lower than for long ones in both environments. The transition from short to long crack behavior occurred at constant $\Delta$K in each environment (15.6 MPa m in air and 10.0 MPa m in seawater(FC)) irrespective of initial Delta K (Delta K(0)). The transition crack length ranged from 0.25 to 1.6 mm and was inversely proportional to $\Delta$K(0). Scanning electron microscope fractography showed that the mechanism of enhanced crack growth rate was associated with secondary crack (SC) formation in air and SC or inter-granular cracking (or both) in seawater (FC). The enhanced FCGR for short cracks was minimized by polarization to -950 mV(SCE). Through an elastic-plastic fracture mechanics analysis using the J-integral parameter it was found that the influence of plastic deformation at the crack tip was approximately independent of crack length (short versus long), and the linear-elastic fracture mechanics analysis gave a realistic representation for fatigue behavior.
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Date Issued: 1992
PURL: http://purl.flvc.org/fcla/dt/12313
Subject Headings: Steel--Fatigue--Environmental aspects, Underwater acoustics, Seawater--Acoustic properties
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: 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: 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: Evaluation of carbon fiber/polyetheretherketone composites exposed to marine microbial communities in laboratory media and natural seawater.
Creator: Sheetz, Andrew Douglas., Florida Atlantic University, Hartt, William H., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: This research proposed to characterize any microbial induced degradation of carbon fiber/polyetheretherketone (PEEK) composites from acid-producing bacteria (APB) and sulfate-reducing bacteria (SRB). Electrochemical impedance spectroscopy (EIS) was used to provide a measure of degradation of the composite system as a function of exposure time. In addition, mechanical testing and microscopic evaluation of the specimens were utilized to determine if changes in the EIS spectra as a function of...
Show moreThis research proposed to characterize any microbial induced degradation of carbon fiber/polyetheretherketone (PEEK) composites from acid-producing bacteria (APB) and sulfate-reducing bacteria (SRB). Electrochemical impedance spectroscopy (EIS) was used to provide a measure of degradation of the composite system as a function of exposure time. In addition, mechanical testing and microscopic evaluation of the specimens were utilized to determine if changes in the EIS spectra as a function of exposure time correlated to changes in the mechanical properties. Results from most EIS scans were consistent with a well-consolidated and undamaged composite system. Changes in the EIS response of specimens exposed to the SRB environment were not matched by a reduction in the flexural strength. Mechanical testing also indicated no reduction in the flexural strength in any of the other exposure environments. Environmental scanning electron microscopy (ESEM)/energy dispersive x-ray spectroscopy (EDS) were inconclusive, though changes in the EDS spectra were seen. No definitive degradation was seen to occur in this composite system.
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Date Issued: 1998
PURL: http://purl.flvc.org/fcla/dt/15531
Subject Headings: Corrosion and anti-corrosives, Composite materials--Biodegradation
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: 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: 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: 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: 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: Hydrogen embrittlement of cathodically protected prestressing steel.
Creator: Kliszowski, Stanislas Henri., Florida Atlantic University, Hartt, William H., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: Cathodic protection is currently recognized as the most practical mean for arresting corrosion of reinforcing steel tendons in existing concrete structures, however, its appropriateness in the case of prestressed concrete is questioned because prestressing steels are relatively susceptible to environmental cracking (hydrogen embrittlement). For the purpose of studying embrittlement tendencies a series of experiments using the slow strain rate technique were performed. The susceptibility to...
Show moreCathodic protection is currently recognized as the most practical mean for arresting corrosion of reinforcing steel tendons in existing concrete structures, however, its appropriateness in the case of prestressed concrete is questioned because prestressing steels are relatively susceptible to environmental cracking (hydrogen embrittlement). For the purpose of studying embrittlement tendencies a series of experiments using the slow strain rate technique were performed. The susceptibility to environmental cracking was compared for different steels corresponding to ASTM grades 270 and 250 polarized at $-$900 and $-1300$ mV (SCE) in deaerated saturated Ca(OH)$\sb2$ solutions. The influence of different notch and pit geometries was studied to simulate the behavior of corroded tendons and investigate the transition between smooth and severely notched specimen behavior. Also evaluated was the evolution of the mechanical properties of tendons after excessive polarization. The different cracking processes are discussed based on test data, fractography and exposures conditions associated with concrete structures.
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Date Issued: 1994
PURL: http://purl.flvc.org/fcla/dt/14999
Subject Headings: Cathodic protection, Metals--Hydrogen embrittlement, Tendons (Prestressed concrete), Prestressed concrete--Deterioration, Prestressed steel construction
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: Performance of anodes in cathodic protection of reinforcing steel in concrete.
Creator: Venugopalan, Sivaraman., Florida Atlantic University, Hartt, William H., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: Experiments were conducted on a simulated reinforced concrete bridge deck to test different anodes as part of a cathodic protection system. Both carbon based and titanium based anodes were tested. All the anodes were driven at predetermined current densities. Current off polarized potentials of steel and anode were monitored over six months. After this period, cores were extracted from slabs containing a part of anode and steel and then broken at the anode-concrete and steel-concrete...
Show moreExperiments were conducted on a simulated reinforced concrete bridge deck to test different anodes as part of a cathodic protection system. Both carbon based and titanium based anodes were tested. All the anodes were driven at predetermined current densities. Current off polarized potentials of steel and anode were monitored over six months. After this period, cores were extracted from slabs containing a part of anode and steel and then broken at the anode-concrete and steel-concrete interface to measure the pH at these interfaces. Differences in the pH values at the anode-concrete interface were compared to determine the performance of the different anodes. Carbon based anodes operated at a higher potential and produced anode corrosion products of lower pH when compared to titanium based anodes.
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Date Issued: 1990
PURL: http://purl.flvc.org/fcla/dt/14658
Subject Headings: Reinforcing bars--Cathodic protection, Reinforced concrete--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: 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: 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: 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)

Steel--Corrosion (11)	+ -
Cathodic protection (10)	+ -
Corrosion and anti-corrosives (6)	+ -
Chlorides (5)	+ -
Seawater corrosion (5)	+ -

Steel--Fatigue (5)	+ -
Reinforced concrete--Corrosion (4)	+ -
Sea-water corrosion (4)	+ -
Steel--Cathodic protection (4)	+ -
Concrete--Corrosion (3)	+ -
Pipelines--Cathodic protection (3)	+ -
Seawater (3)	+ -
Underwater pipelines (3)	+ -
Composite reinforced concrete (2)	+ -
Concrete--Deterioration (2)	+ -
Offshore structures (2)	+ -
Prestressed concrete--Corrosion (2)	+ -
Prestressed steel construction (2)	+ -
Reinforced concrete construction (2)	+ -
Reinforcing bars--Cathodic protection (2)	+ -
Steel, High strength--Brittleness (2)	+ -
Steel, Structural--Corrosion (2)	+ -
Steel, Structural--Fatigue (2)	+ -
Steel, Structural--Testing (2)	+ -
Steel--Fracture (2)	+ -
Tendons (Prestressed concrete) (2)	+ -
Welded joints--Fatigue (2)	+ -
Adhesives (1)	+ -
Alkali-aggregate reactions (1)	+ -
Aluminum--Corrosion (1)	+ -

Department of Ocean and Mechanical Engineering (54)	+ -
Florida Atlantic University (54)	+ -
Suarez, Jorge Alejandro (2)	+ -
Wang, Weiqing. (2)	+ -
Chen, Shaowei. (1)	+ -

Deshayes, Frederic Rene. (1)	+ -
KRISHNAKUMAR, RENGAN. (1)	+ -
KRISHNAMURTHY, RAVI M. (1)	+ -
KUNJAPUR, MADANA MOHAN. (1)	+ -
Kim, Kijoon. (1)	+ -
Kliszowski, Stanislas Henri. (1)	+ -
Kumria, Chetan Chand. (1)	+ -
LEE, AI-KUO. (1)	+ -
Le Floch, Anne. (1)	+ -
Lee, Seung-Kyoung (1)	+ -
Lemieux, Edward John. (1)	+ -
Leroux, Virginie Edwige. (1)	+ -
Li, Yong. (1)	+ -
Luo, Jiunn-Shyong (1)	+ -
Lysogorski, Diane K. (1)	+ -
MAO, WEI-YUN. (1)	+ -
MILLER, RONALD LAWRENCE. (1)	+ -
Mantel, Katherine Elizabeth. (1)	+ -
Mathew, Ivan. (1)	+ -
McIntyre, Jack F. (1)	+ -
NEROLICH, SHAUN MICHAEL. (1)	+ -
Nallur, Padmanabha. (1)	+ -
Nam, Jingak. (1)	+ -

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