Current Search: Concrete--Corrosion (x)
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- Title
- THE MECHANISM OF CONCRETE CRACKING IN SEAWATER DUE TO EMBEDDED METAL CORROSION.
- Creator
- GRIMES, WILLIAM DARWIN., Florida Atlantic University, Hartt, William H.
- Abstract/Description
-
Investigation of concrete-rebar interface conditions was conducted for the purpose of identifying governing parameters of the concrete cracking process in seawater. Experiments included an examination of chloride ion penetration, concrete pH as a function of metallic chloride concentration, and pH distribution within reinforced, impressed current specimens. Metal-concrete systems investigated included iron, molybdenum, cadmium, zinc, aluminum, copper, and nickel. Simplified models of the...
Show moreInvestigation of concrete-rebar interface conditions was conducted for the purpose of identifying governing parameters of the concrete cracking process in seawater. Experiments included an examination of chloride ion penetration, concrete pH as a function of metallic chloride concentration, and pH distribution within reinforced, impressed current specimens. Metal-concrete systems investigated included iron, molybdenum, cadmium, zinc, aluminum, copper, and nickel. Simplified models of the rebar corrosion process are presented in conjunction with electrochemical analysis of the projected interface chemistry. Results indicated that chlorinities greater than seawater concentration may occur as a result of potential gradients in reinforced concrete. Laboratory simulations of interface chemistry indicated that metallic and chloride ions may produce an acid pH in concrete solutions when present in sufficiently high concentrations. Heasurements of pH on the fracture face of impressed current corrosion specimens indicated localized acidic conditions can develop.
Show less - Date Issued
- 1977
- PURL
- http://purl.flvc.org/fcla/dt/13885
- Subject Headings
- Reinforced concrete--Corrosion
- Format
- Document (PDF)
- Title
- SERVICEABILITY OF REINFORCED CONCRETE BEAMS SUBJECTED TO ACCELERATED CORROSION (ACOUSTIC EMISSION, DAMAGE, REMAINING STRENGTH/LIFE, TESTING).
- Creator
- TITUS, REJI NINAN K., Florida Atlantic University, Reddy, Dronnadula V., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
- Abstract/Description
-
Steel reinforced concrete beams were placed in contact with seawater in a state of accelerated corrosion, for varying periods of time. Some of them were simultaneously monitored for acoustic emission and the results were analyzed to evaluate the effectiveness of acoustic emission as a non-destructive monitor of corrosion induced damage. It was shown that, in a laboratory environment, counts are good indicators of the extent of corrosion damage. A review of acoustic emission monitoring...
Show moreSteel reinforced concrete beams were placed in contact with seawater in a state of accelerated corrosion, for varying periods of time. Some of them were simultaneously monitored for acoustic emission and the results were analyzed to evaluate the effectiveness of acoustic emission as a non-destructive monitor of corrosion induced damage. It was shown that, in a laboratory environment, counts are good indicators of the extent of corrosion damage. A review of acoustic emission monitoring techniques and theoretical background is included. The concrete beams were tested for flexural strength after being corroded. Reduction in rebar section was found to have a very good correlation with da mage. An attempt was made to predict remaining life of the beams based on data obtained from the tests.
Show less - Date Issued
- 1986
- PURL
- http://purl.flvc.org/fcla/dt/14310
- Subject Headings
- Reinforced concrete--Corrosion
- Format
- Document (PDF)
- Title
- THE CORROSION OF EPOXY COATED REINFORCING STEEL.
- Creator
- WANG, YUN TSO, Florida Atlantic University
- Abstract/Description
-
Tests were conducted using 10 cm. (3.93 in.) lengths of both epoxy coated and bare steel reinforcing rods in simulated concrete environments of varying pH and chloride ion levels. Polarization studies using cathodic scan techniques were used to characterize the quality of the epoxy coating. In all the environments tested, bars with more defects required larger currents at a given potential than did the bars with few defects. Corrosion potential measurements in passive environments showed...
Show moreTests were conducted using 10 cm. (3.93 in.) lengths of both epoxy coated and bare steel reinforcing rods in simulated concrete environments of varying pH and chloride ion levels. Polarization studies using cathodic scan techniques were used to characterize the quality of the epoxy coating. In all the environments tested, bars with more defects required larger currents at a given potential than did the bars with few defects. Corrosion potential measurements in passive environments showed significant fluctuations from day to day, making it difficult to use potential measurement for corrosion characterization. Galvanic couples between epoxy coated and uncoated bars indicated that galvanic currents increased as the differences in the corrosion potentials increased and also as the chloride ion content of the environment increased from 0 to 0.05 M.
Show less - Date Issued
- 1980
- PURL
- http://purl.flvc.org/fcla/dt/14010
- Subject Headings
- Concrete--Corrosion, Seawater Corrosion
- Format
- Document (PDF)
- Title
- INVESTIGATION OF CORROSION OF REINFORCING STEEL BY USING ULTRASONIC TECHNIQUES AND SPECTRAL ANALYSIS.
- Creator
- WANG, YUN YU, Florida Atlantic University
- Abstract/Description
-
In this investigation an ultrasonic technique and spectral analysis were employed to detect corrosion of reinforcing steel in concrete under conditions of accelerated testing. Various properties of a transmitted ultrasonic pulse were determined, and it was concluded that the transfer function provided the most realistic possibility for detection of corrosion and cracking. The most meaningful correlations of the transfer function with corrosion and cracking events were for situations where the...
Show moreIn this investigation an ultrasonic technique and spectral analysis were employed to detect corrosion of reinforcing steel in concrete under conditions of accelerated testing. Various properties of a transmitted ultrasonic pulse were determined, and it was concluded that the transfer function provided the most realistic possibility for detection of corrosion and cracking. The most meaningful correlations of the transfer function with corrosion and cracking events were for situations where the temporal variation of the transfer function at the particular frequency was small. The appropriateness of ultrasonic parameters with regard to problems involving corrosion of reinforcing steel is discussed.
Show less - Date Issued
- 1979
- PURL
- http://purl.flvc.org/fcla/dt/14006
- Subject Headings
- Concrete--Corrosion, Seawater Corrosion
- Format
- Document (PDF)
- Title
- ACOUSTIC EMISSION ASSOCIATED WITH EMBEDDED METAL CORROSION IN A CONCRETE SLAB.
- Creator
- MARSHALL, RICHARD MELBOURNE., Florida Atlantic University, Dunn, Stanley E., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
- Abstract/Description
-
Measured values of attenuation with distance, amplitude distribution, and propagation velocity of acoustic emissions associated with embedded metcil corrosion induced cracking in a concrete slab are presented. An extensive review of acoustic emission signal processing techniques and theoretical background material is also included. The study points out how attenuation and propagation velocity of the acoustic emission signal affects various signal processing techniques and verifies an...
Show moreMeasured values of attenuation with distance, amplitude distribution, and propagation velocity of acoustic emissions associated with embedded metcil corrosion induced cracking in a concrete slab are presented. An extensive review of acoustic emission signal processing techniques and theoretical background material is also included. The study points out how attenuation and propagation velocity of the acoustic emission signal affects various signal processing techniques and verifies an amplitude distribution spreading rrodel. The need for further defirlition of attentuation values caused by fluid loading of the concrete surface is also discussed.
Show less - Date Issued
- 1982
- PURL
- http://purl.flvc.org/fcla/dt/14129
- Subject Headings
- Reinforced concrete--Corrosion, Acoustic emission testing
- Format
- Document (PDF)
- Title
- DETECTION OF DETERIORATION OF REINFORCED CONCRETE BY ACOUSTIC EMISSION TECHNIQUES.
- Creator
- WENG, MING-YUAN., Florida Atlantic University, Dunn, Stanley E., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
- Abstract/Description
-
In this investigation acoustic emission techniques were employed to detect deterioration of reinforced concrete. As a result of various laboratory tests, acoustic emission activity was found to be due to development of cracking only. Acoustic emission techniques were able to locate cracks in a specimen by linear location. Various acoustic emission parameters such as amplitude, signal shape and frequency were also analyzed and discussed. It was concluded that acoustic emission techniques...
Show moreIn this investigation acoustic emission techniques were employed to detect deterioration of reinforced concrete. As a result of various laboratory tests, acoustic emission activity was found to be due to development of cracking only. Acoustic emission techniques were able to locate cracks in a specimen by linear location. Various acoustic emission parameters such as amplitude, signal shape and frequency were also analyzed and discussed. It was concluded that acoustic emission techniques provided a feasible method for detection of deterioration and cracking of steel reinforced structures in laboratory studies as well as in a field environment.
Show less - Date Issued
- 1980
- PURL
- http://purl.flvc.org/fcla/dt/14042
- Subject Headings
- Acoustic emission testing, Reinforced concrete--Corrosion
- Format
- Document (PDF)
- Title
- The assessment of bond for cathodically polarized pretensioning steel in concrete.
- Creator
- Dohlen, Knut Herman., Florida Atlantic University, Hartt, William H.
- Abstract/Description
-
Pretensioned concrete members require a certain bond strength between the steel and concrete to maintain prestress force. Previous studies have indicated that when reinforcing steel in concrete is cathodically polarized, a chemical change of the cement near the steel-concrete interface occurs; and this can reduce the bond strength. In the present research experiments were conducted with concrete specimens that contained either a non-stressed seven wire steel tendon or a single strand through...
Show morePretensioned concrete members require a certain bond strength between the steel and concrete to maintain prestress force. Previous studies have indicated that when reinforcing steel in concrete is cathodically polarized, a chemical change of the cement near the steel-concrete interface occurs; and this can reduce the bond strength. In the present research experiments were conducted with concrete specimens that contained either a non-stressed seven wire steel tendon or a single strand through the longitudinal direction. The specimens were cathodically polarized with current densities ranging between 50 and 2500 mA/m^2 of steel. Upon achieving a pre-determined charge density transfer, the steel was pulled relative to the concrete until the bond was broken. Results indicate that a total charge density transfer of up to 14000 A*h/m^2 of steel, may introduce an average 16 percent decrease in ultimate bond strength. This and other data were evaluated in order to assess if cathodic protection, as utilized for corrosion control, is likely to compromise structural integrity of pretensioned concrete members and structures.
Show less - Date Issued
- 1998
- PURL
- http://purl.flvc.org/fcla/dt/15543
- Subject Headings
- Cathodic protection, Reinforced concrete--Corrosion
- Format
- Document (PDF)
- Title
- Acoustic emission investigation of marine corrosion-induced and external load-induced cracking of concrete.
- Creator
- Sailappan, R. N., Florida Atlantic University, Reddy, Dronnadula V., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
- Abstract/Description
-
The acoustic emission investigations reported herein are divided into two experimental sets. In the first, the concrete specimens were stressed internally, and the resulting acoustic emissions were monitored. In the second, specimens were subjected to fracture mechanics tests and simultaneously studied for AE signals. For both sets, two kinds of concrete were studied--regular concrete and concrete containing fly ash. The specimens were stressed internally by subjecting them to an accelerated...
Show moreThe acoustic emission investigations reported herein are divided into two experimental sets. In the first, the concrete specimens were stressed internally, and the resulting acoustic emissions were monitored. In the second, specimens were subjected to fracture mechanics tests and simultaneously studied for AE signals. For both sets, two kinds of concrete were studied--regular concrete and concrete containing fly ash. The specimens were stressed internally by subjecting them to an accelerated state of corrosion in a marine environment. The corroded specimens were then tested for impact and flexural strengths to study the effect of fly ash replacement on rebar corrosion in a marine environment, and to ascertain any correlation between the monitored AE signals and residual strength. Furthermore, an attempt was made to predict the remaining life of the specimens. For the externally stressed specimens, AE was used to determine the load at initiation of unstable crack propagation terms of ultimate load. These tests have immediate and relevant applications to field problems.
Show less - Date Issued
- 1991
- PURL
- http://purl.flvc.org/fcla/dt/14700
- Subject Headings
- Acoustic emission testing, Concrete--Corrosion, Concrete--Cracking
- 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.
Show less - Date Issued
- 1999
- PURL
- http://purl.flvc.org/fcla/dt/15665
- Subject Headings
- Reinforced concrete--Corrosion, Cathodic protection, Zinc coating
- Format
- Document (PDF)
- Title
- Analytical evaluation of marine concrete pile repairs.
- Creator
- Saleh, Zaher A. Abou., Florida Atlantic University, Reddy, Dronnadula V., College of Engineering and Computer Science, Department of Civil, Environmental and Geomatics Engineering
- Abstract/Description
-
The purpose of the thesis is to determine and compare the performance characteristics of marine piles corroded by chloride diffusion and repaired by several different methods for both uncracked and cracked concrete and to determine their structural integrity. The long-term objective is the comparison of the analytical values with those from an on-going experimental evaluation. The time for chloride concentration reach the threshold value that initiates corrosion in the reinforcement has been...
Show moreThe purpose of the thesis is to determine and compare the performance characteristics of marine piles corroded by chloride diffusion and repaired by several different methods for both uncracked and cracked concrete and to determine their structural integrity. The long-term objective is the comparison of the analytical values with those from an on-going experimental evaluation. The time for chloride concentration reach the threshold value that initiates corrosion in the reinforcement has been determined by Fick's law, extended to 2-D and 3-D chloride diffusion, for (a) uncracked concrete, and (b) for cracked concrete with the Simplified Smeared Approach (SSA). The structural integrity of the concrete circular pile is compared before and alter repair, by (a) finite element modeling using ANSYS software with the maximum deflection, and (b) beam strength analysis to find the moment capacity for cracked and ultimate conditions. The overall findings indicate the adequacy of the repair procedures.
Show less - Date Issued
- 2003
- PURL
- http://purl.flvc.org/fcla/dt/13062
- Subject Headings
- Concrete piling, Reinforced concrete--Corrosion, Seawater corrosion
- 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.
Show less - Date Issued
- 1990
- PURL
- http://purl.flvc.org/fcla/dt/14658
- Subject Headings
- Reinforcing bars--Cathodic protection, Reinforced concrete--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.
Show less - 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.
Show less - 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
- Corrosion Propagation of Rebar Embedded in High Performance Concrete.
- Creator
- Nazim, Manzurul, Presuel-Moreno, Francisco, Florida Atlantic University, College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
- Abstract/Description
-
The FDOT has been using supplementary cementitious materials while constructing steel reinforced concrete marine bridge structures for over 3 decades. Previous findings indicated that such additions in concrete mix makes the concrete more durable. To better understand corrosion propagation of rebar in high performance concrete: mature concrete samples that were made (2008/2009) with Portland cement, a binary mix, a ternary mix and recently prepared (April 2016 with 50% OPC + 50% slag and 80%...
Show moreThe FDOT has been using supplementary cementitious materials while constructing steel reinforced concrete marine bridge structures for over 3 decades. Previous findings indicated that such additions in concrete mix makes the concrete more durable. To better understand corrosion propagation of rebar in high performance concrete: mature concrete samples that were made (2008/2009) with Portland cement, a binary mix, a ternary mix and recently prepared (April 2016 with 50% OPC + 50% slag and 80% OPC + 20% Fly ash) concrete samples were considered. None of these concretes had any admixed chloride to start with. An accelerated chloride transport process was used to drive chloride ions into the concrete so that chlorides reach and exceed thechloride threshold at the rebar surface and initiate corrosion. Electrochemical measurements were taken at regular intervals (during and after the electro-migration process) to observe the corrosion propagation in each sample.
Show less - Date Issued
- 2017
- PURL
- http://purl.flvc.org/fau/fd/FA00004941, http://purl.flvc.org/fau/fd/FA00004941
- Subject Headings
- Reinforced concrete--Corrosion., Reinforced concrete--Chemical resistance., Reinforced concrete--Deterioration., Concrete--Corrosion., Concrete--Mechanical properties.
- Format
- Document (PDF)
- Title
- Bulk diffusion of high performance concrete specimens exposed to different levels of sodium chloride and seawater.
- Creator
- Arias, Wendy J., Presuel-Moreno, Francisco, Florida Atlantic University, College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
- Abstract/Description
-
The purpose of this study was to investigate the performance to chloride penetration of specimens made with three base compositions (three different supplementary cementitious materials) and water to cementitious ratios of 0.35, 0.41, or 0.47. The specimens were subjected to bulk diffusion test or full immersion. The mixes were exposed to 0.1 M, 0.6 M, or 2.8 M sodium chloride solution for different periods of time. Also, partially immersed specimens were exposed to indoor and outdoor...
Show moreThe purpose of this study was to investigate the performance to chloride penetration of specimens made with three base compositions (three different supplementary cementitious materials) and water to cementitious ratios of 0.35, 0.41, or 0.47. The specimens were subjected to bulk diffusion test or full immersion. The mixes were exposed to 0.1 M, 0.6 M, or 2.8 M sodium chloride solution for different periods of time. Also, partially immersed specimens were exposed to indoor and outdoor exposures (tidal, splash, barge). Chloride concentration profiles were obtained and the apparent diffusion coefficient was calculated. The skin effect was found only on some chloride profiles exposed to 0.1 M sodium chloride solution. The chloride binding capacity was calculated; specimens with 20% Fly Ash and 8% Silica Fume had the highest binding capacity (70.99%). The apparent diffusivity coefficient was found to be dependent on the curing regime as well as the water to cement ratio. The correlation between effective resistivity and apparent diffusion coefficient was determined.
Show less - Date Issued
- 2014
- PURL
- http://purl.flvc.org/fau/fd/FA00004076, http://purl.flvc.org/fau/fd/FA00004076
- Subject Headings
- Bulk solids flow, Concrete -- Corrosion, Concrete, Effect of salt on, Reinforced concrete -- Deterioration, Sustainable construction
- Format
- Document (PDF)
- Title
- Fire resistance of corroded structural concrete.
- Creator
- Martinez, Fernando Jose, Reddy, Dronnadula V., Florida Atlantic University, College of Engineering and Computer Science, Department of Civil, Environmental and Geomatics Engineering
- Abstract/Description
-
One of the major causes of structural repairs worldwide is the corrosion of reinforced concrete structures, such as residential buildings and piers, which are exposed to harsh marine environments. This investigation aims to provide experimental evidence of the fire resistance of corroded high strength reinforced concrete. For this, 14 reinforced concrete beams of three different concrete mix designs (different strengths) were prepared along with concrete cylinders for compression strength...
Show moreOne of the major causes of structural repairs worldwide is the corrosion of reinforced concrete structures, such as residential buildings and piers, which are exposed to harsh marine environments. This investigation aims to provide experimental evidence of the fire resistance of corroded high strength reinforced concrete. For this, 14 reinforced concrete beams of three different concrete mix designs (different strengths) were prepared along with concrete cylinders for compression strength testing (ASTM C39). After proper moist curing, all beams were corroded, in two phases, with impressed current, then “crack scored ”for corrosion evaluation, after which half were exposed to fire, also in two phases, following the ASTM E-119-12 time-temperature curve, using a gas kiln. The fire damage was evaluated and compared between phases by using Ultrasonic Pulse Velocity technology. Finally, all specimens were tested for flexural strength by using the third-point loading method (ASTM C78) and the effects of fire on the corroded beams were analyzed according to the level of corrosion.
Show less - Date Issued
- 2014
- PURL
- http://purl.flvc.org/fau/fd/FA00004304, http://purl.flvc.org/fau/fd/FA00004304
- Subject Headings
- Concrete -- Effect of temperature on, Fire resistant materials, Reinforced concrete -- Corrosion, Thermodynamics
- Format
- Document (PDF)
- Title
- ACOUSTIC EMISSIONS TESTING AS A NONDESTRUCTIVE MONITOR OF CONCRETE CRACKING DUE TO REINFORCING BAR CORROSION.
- Creator
- YOUNG, JAMES DANIEL., Florida Atlantic University, Dunn, Stanley E., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
- Abstract/Description
-
Steel reinforced concrete specimens of loaded and unloaded configuration were placed in contact with seawater in a state of accelerated corrosion. They were simultaneously monitored for acoustic emission and the results were analyzed in an evaluation of the use of acoustic emission as a nondestructive monitor of corrosion induced cracking. It was shown that, in a laboratory environment, counts and amplitude information are sensitive indicators of the levels of cracking within the concrete...
Show moreSteel reinforced concrete specimens of loaded and unloaded configuration were placed in contact with seawater in a state of accelerated corrosion. They were simultaneously monitored for acoustic emission and the results were analyzed in an evaluation of the use of acoustic emission as a nondestructive monitor of corrosion induced cracking. It was shown that, in a laboratory environment, counts and amplitude information are sensitive indicators of the levels of cracking within the concrete specimen; and thereby the degree of corrosion damage may be inferred. Analytical models applicable to the representation of acoustic emission amplitude distribution are discussed also.
Show less - Date Issued
- 1982
- PURL
- http://purl.flvc.org/fcla/dt/14141
- Subject Headings
- Reinforced concrete--Cracking, Reinforced concrete--Corrosion, Acoustic emission testing
- Format
- Document (PDF)
- Title
- Accelerated durability testing of reinforced and unreinforced concretes in a simulated marine environment.
- Creator
- Jeedigunta, Giridhar V., Florida Atlantic University, Reddy, Dronnadula V.
- Abstract/Description
-
Durability of marine reinforced and unreinforced concretes was tested under accelerated environmental conditions. The specimens were subjected to alternate wet and dry cycles in specially constructed durability testing tanks. The specific objective was to evaluate the durability of different types of concretes with varying water-cementitious material ratios (0.3, 0.4, and 0.6), cement types (Types I and II), mineral admixtures (blast furnace slag, fly ash, microsilica), and steel types (black...
Show moreDurability of marine reinforced and unreinforced concretes was tested under accelerated environmental conditions. The specimens were subjected to alternate wet and dry cycles in specially constructed durability testing tanks. The specific objective was to evaluate the durability of different types of concretes with varying water-cementitious material ratios (0.3, 0.4, and 0.6), cement types (Types I and II), mineral admixtures (blast furnace slag, fly ash, microsilica), and steel types (black, galvinized and epoxy-coated rebars). The unreinforced cylindrical specimens were tested for compressive and splitting tensile strengths and the reinforced prismatic specimens for corrosion. The test results after 300 cycles of accelerated exposure indicated the adverse effects of the marine environment on the durability of concretes, resulting in loss of strength and corrosion resistance. The specimens with lower w/c ratios (0.3 and 0.4) showed good performance, whether or not they were admixture modified. However, mineral admixture inclusions improved the properties of strength and corrosion resistance of the specimens even with high w/c ratios (0.6). The specimens with regular rebars indicated least resistance to corrosion induced from the accelerated marine exposure compared to the ones with galvanized and epoxy-coated rebars.
Show less - Date Issued
- 1998
- PURL
- http://purl.flvc.org/fcla/dt/15551
- Subject Headings
- Reinforced concrete--Corrosion, Reinforced concrete--Environmental testing, Concrete--Environmental testing
- Format
- Document (PDF)
- Title
- Strength and durability of fly ash-based fiber-reinforced geopolymer concrete in a simulated marine environment.
- Creator
- Martinez Rivera, Francisco Javier, Sobhan, Khaled, College of Engineering and Computer Science, Department of Civil, Environmental and Geomatics Engineering
- Abstract/Description
-
This research is aimed at investigating the corrosion durability of polyolefin fiber-reinforced fly ash-based geopolymer structural concrete (hereafter referred to as GPC, in contradistinction to unreinforced geopolymer concrete referred to as simply geopolymer concrete), where cement is completely replaced by fly ash, that is activated by alkalis, sodium hydroxide and sodium silicate. The durability in a marine environment is tested through an electrochemical method for accelerated corrosion...
Show moreThis research is aimed at investigating the corrosion durability of polyolefin fiber-reinforced fly ash-based geopolymer structural concrete (hereafter referred to as GPC, in contradistinction to unreinforced geopolymer concrete referred to as simply geopolymer concrete), where cement is completely replaced by fly ash, that is activated by alkalis, sodium hydroxide and sodium silicate. The durability in a marine environment is tested through an electrochemical method for accelerated corrosion. The GPC achieved compressive strengths in excess of 6,000 psi. Fiber reinforced beams contained polyolefin fibers in the amounts of 0.1%, 0.3%, and 0.5% by volume. After being subjected to corrosion damage, the GPC beams were analyzed through a method of crack scoring, steel mass loss, and residual flexural strength testing. Fiber reinforced GPC beams showed greater resistance to corrosion damage with higher residual flexural strength. This makes GPC an attractive material for use in submerged marine structures.
Show less - Date Issued
- 2013
- PURL
- http://purl.flvc.org/fau/fd/FA0004037
- Subject Headings
- Concrete mixing -- Quality control, Green chemistry, Polymer composites, Reinforced concrete -- Corrosion -- Testing, Reinforced concrete 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.
Show less - 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)