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STRUCTURAL INTEGRITY OF CALCAREOUS DEPOSIT - REHABILITATED MARINE REINFORCED CONCRETE
Title
STRUCTURAL INTEGRITY OF CALCAREOUS DEPOSIT - REHABILITATED MARINE REINFORCED CONCRETE.
Creator
DOHLEN, STENER., Florida Atlantic University
Abstract/Description
Corrosion-induced spalling of reinforced concrete and prestressed concrete is a major problem in coastal structures. Statistics on the rehabilitation and replacement of damaged concrete in the U.S.A. indicates substantial expenditure. This study is an investigation of the use of electro-deposited minerals for in-situ concrete repair in a cost-effective manner to extend the service life for marine reinforced concrete structures. During the first phase of this investigation, the reinforcing...
Show moreCorrosion-induced spalling of reinforced concrete and prestressed concrete is a major problem in coastal structures. Statistics on the rehabilitation and replacement of damaged concrete in the U.S.A. indicates substantial expenditure. This study is an investigation of the use of electro-deposited minerals for in-situ concrete repair in a cost-effective manner to extend the service life for marine reinforced concrete structures. During the first phase of this investigation, the reinforcing steel in specimens was corroded by an impressed voltage technique to a point where concrete cracking occurred. The second phase addressed the rehabilitation in which the calcareous deposits were precipitated in the cracks by an impressed cathodic current. This investigation included both laboratory testing with once-through circulating seawater and field testing in the ocean environment. The findings indicate that the structural strength of the concrete specimens decreased as a result of the impressed voltage.
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Date Issued
1988
PURL
http://purl.flvc.org/fcla/dt/14407
Subject Headings
Reinforced concrete--Cracking, Seawater
Format
Document (PDF)
Acoustic emission investigation of marine corrosion-induced and external load-induced cracking of concrete
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.
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Date Issued
1991
PURL
http://purl.flvc.org/fcla/dt/14700
Subject Headings
Acoustic emission testing, Concrete--Corrosion, Concrete--Cracking
Format
Document (PDF)
Durability and fracture toughness of fly ash concrete in the marine environment
Title
Durability and fracture toughness of fly ash concrete in the marine environment.
Creator
Lee, Seung-Kyoung, Florida Atlantic University, Reddy, Dronnadula V., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description
This thesis presents the experimental investigation of durability and fracture toughness (K IC) of fly ash concrete in the marine environment. The findings indicate that the deterioration rate of durability parameters, such as compressive strength, weight loss, and dynamic modulus of elasticity, due to 450 wet and dry cycles exposure (the Accelerated Durability Testing), was inversely proportional to the amount of fly ash replacement. On the other hand, tensile strength properties, such as...
Show moreThis thesis presents the experimental investigation of durability and fracture toughness (K IC) of fly ash concrete in the marine environment. The findings indicate that the deterioration rate of durability parameters, such as compressive strength, weight loss, and dynamic modulus of elasticity, due to 450 wet and dry cycles exposure (the Accelerated Durability Testing), was inversely proportional to the amount of fly ash replacement. On the other hand, tensile strength properties, such as modulus of rupture and fracture toughness, were independent of fly ash replacement, but increased with the period of accelerated testing. The mean K IC values of fly ash concrete mixes showed that they are closely related to their compressive strengths and size effects. According to AE, unstable crack propagation initiated at 93-97% maximum load. With SEM observations, it was found that crystallized particles were precipitated in the void spaces due to chemical reaction between the cement paste and seawater.
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Date Issued
1990
PURL
http://purl.flvc.org/fcla/dt/14614
Subject Headings
Fly ash, Concrete--Cracking, Fracture mechanics, Concrete--Testing
Format
Document (PDF)
Crack propagation in concrete structural members strengthened with bonded fiber reinforced polymer plastic (FRP) laminates
Title
Crack propagation in concrete structural members strengthened with bonded fiber reinforced polymer plastic (FRP) laminates.
Creator
Gervois, Gonzague., Florida Atlantic University, Reddy, Dronnadula V.
Abstract/Description
This thesis presents an experimental and analytical investigation of concrete structural members strengthened with externally bonded composite laminates with varying configurations. Parameters, such as size, type of laminate, debond, etc., are evaluated from the viewpoint of stress patterns and their influence on interfacial debonds. Stress patterns in the structure and stress intensity factors around crack tips are determined using a finite element model developed for this purpose. The study...
Show moreThis thesis presents an experimental and analytical investigation of concrete structural members strengthened with externally bonded composite laminates with varying configurations. Parameters, such as size, type of laminate, debond, etc., are evaluated from the viewpoint of stress patterns and their influence on interfacial debonds. Stress patterns in the structure and stress intensity factors around crack tips are determined using a finite element model developed for this purpose. The study also includes a precise description of cracking and the failure function of each parameter investigated. Besides the development of an innovative finite element program, which enables the study of interfacial cracks in structures with highly nonlinear behavior and multiple irregular cracking patterns, the significant contributions include the effect of laminate geometry, the inefficiency of laminate prestressing, the negative effect of end debond, and the insignificant effect of midspan debond on the cracking and the strength of a laminated concrete structural member.
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Date Issued
1997
PURL
http://purl.flvc.org/fcla/dt/15498
Subject Headings
Fiber reinforced plastics, Laminated materials, Concrete--Cracking
Format
Document (PDF)
ACOUSTIC EMISSIONS TESTING AS A NONDESTRUCTIVE MONITOR OF CONCRETE CRACKING DUE TO REINFORCING BAR CORROSION
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.
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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)
CRACKING OF CONCRETE DUE TO CORROSION OF VARIOUS EMBEDDED METALS
Title
CRACKING OF CONCRETE DUE TO CORROSION OF VARIOUS EMBEDDED METALS.
Creator
TURNER, DEAN HUDSON., Florida Atlantic University, Hartt, William H., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description
The objective of this investigati.on was to contribute to the determination of a suitable metallic coating for steel reinforcement in concrete exposed to a marine environment and possibly to stray current. Concrete specimens embedded with steel, aluminum, cadmium, copper, molybdenum, nickel, and galvanized steel were exposed to sea water. Direct current was impressed on these to accelerate corrosion of the reinforcement so that cracking of the concrete could be observed within the time limit...
Show moreThe objective of this investigati.on was to contribute to the determination of a suitable metallic coating for steel reinforcement in concrete exposed to a marine environment and possibly to stray current. Concrete specimens embedded with steel, aluminum, cadmium, copper, molybdenum, nickel, and galvanized steel were exposed to sea water. Direct current was impressed on these to accelerate corrosion of the reinforcement so that cracking of the concrete could be observed within the time limit of the investigation. Aluminum, cadmium, copper, and nickel were found to have no beneficial effect on concrete cracking as compared to steel. In addition, no correlation between oxide-metal volume ratio and concrete time-to-cracking could be observed. It was found that corrosion of molybdenum has little or no tendency to crack concrete and its corrosion potential and active behavior approximates that of steel, indicating it may be an excellent coating.
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Date Issued
1976
PURL
http://purl.flvc.org/fcla/dt/13820
Subject Headings
Reinforced concrete--Cracking, Underwater concrete construction, Reinforced concrete--Corrosion
Format
Document (PDF)
Volumetric changes of cement paste under exposure to the simulated corrosion products of steel and their influence on cracking susceptibility
Title
Volumetric changes of cement paste under exposure to the simulated corrosion products of steel and their influence on cracking susceptibility.
Creator
Bedu, Philippe., Florida Atlantic University, Hartt, William H.
Abstract/Description
Dimensional changes of thin cement paste specimens were monitored during exposure to distilled water, hydrochloric acid, alkaline and FeCl$\sb2$ solutions; and comparison was made with the experimental results obtained by other authors. Post experimental examination of reaction products formed on the specimen surface exposed to FeCl$\sb2$ was conducted using X-Ray diffraction. The data resulting from the measured dimensional changes were input to a finite element model to project the stresses...
Show moreDimensional changes of thin cement paste specimens were monitored during exposure to distilled water, hydrochloric acid, alkaline and FeCl$\sb2$ solutions; and comparison was made with the experimental results obtained by other authors. Post experimental examination of reaction products formed on the specimen surface exposed to FeCl$\sb2$ was conducted using X-Ray diffraction. The data resulting from the measured dimensional changes were input to a finite element model to project the stresses that should occur in association with localized corrosion of embedded steel and wetting of adjacent cement by aqueous FeCl$\sb2$. Implications of the findings with regard to cement and concrete cracking in association with embedded metal corrosion are discussed.
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Date Issued
1993
PURL
http://purl.flvc.org/fcla/dt/14990
Subject Headings
Reinforced concrete--Corrosion, Reinforced concrete--Cracking, Steel--Corrosion, Volumetric analysis
Format
Document (PDF)
Behavior of repaired concrete structures with advanced composites in cold environment
Title
Behavior of repaired concrete structures with advanced composites in cold environment.
Creator
Thayer, Chad C., Florida Atlantic University, Arockiasamy, Madasamy, College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description
This report presents the experimental and theoretical studies on the feasibility of using CFRP laminates for strengthening damaged reinforced concrete beams in cold environment. Experimental work includes investigation on fatigue strength, ultimate capacity and failure modes of repaired reinforced concrete beams in cold environment and room temperature. The repaired concrete beams subjected to fatigue in cold environment exhibit fewer number of cracks than those observed in beams at room...
Show moreThis report presents the experimental and theoretical studies on the feasibility of using CFRP laminates for strengthening damaged reinforced concrete beams in cold environment. Experimental work includes investigation on fatigue strength, ultimate capacity and failure modes of repaired reinforced concrete beams in cold environment and room temperature. The repaired concrete beams subjected to fatigue in cold environment exhibit fewer number of cracks than those observed in beams at room temperature. The crack propagation and resulting damage were faster in beams tested in room temperature than those at cold temperatures. The study also includes investigation of thermal response of repaired plain concrete beams with CFRP laminates subjected to thermal cycles. Analytical studies on the distributed shear forces and peeling forces of repaired reinforced concrete beams were carried out to analyze the interaction between the laminate and the concrete interface. The temperature distribution and strains developed by the temperature differential are determined in the repaired plain concrete beams subjected to thermal cycles and the analytical results compared with the measured values.
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Date Issued
1997
PURL
http://purl.flvc.org/fcla/dt/15517
Subject Headings
Reinforced concrete--Cracking, Fiber reinforced plastics, Composite materials--Effect of environment on, Fibrous composites--Fatigue
Format
Document (PDF)
Evaluation of Chloride Threshold for Steel Fiber Reinforced Concrete Composited in Aggressively Corrosive Environments
Title
Evaluation of Chloride Threshold for Steel Fiber Reinforced Concrete Composited in Aggressively Corrosive Environments.
Creator
Vogel, Dietrich H., Presuel-Moreno, Francisco, Florida Atlantic University, College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description
Highway drainage pipes utilize concrete reinforced with steel wire to help mitigate water, earth, and traffic loads. Drainage pipes reinforced with zinc electroplated steel fibers offer a lower steel alternative to traditional steel wire cage reinforcements. The objective of the thesis research was to determine the physical and electrochemical characteristics of zinc electroplated steel fiber corrosion propagation. Experimental programs include: Fracture analysis of zinc electroplated steel...
Show moreHighway drainage pipes utilize concrete reinforced with steel wire to help mitigate water, earth, and traffic loads. Drainage pipes reinforced with zinc electroplated steel fibers offer a lower steel alternative to traditional steel wire cage reinforcements. The objective of the thesis research was to determine the physical and electrochemical characteristics of zinc electroplated steel fiber corrosion propagation. Experimental programs include: Fracture analysis of zinc electroplated steel fibers embedded in dry-cast concrete pipes exposed to varying chloride concentrations; Visual analysis of zinc electroplated steel fibers embedded in concrete exposed to varying chloride concentrations; Electrochemical analysis of zinc electroplated steel fibers embedded in concrete exposed to varying chlorides; Chloride threshold determination for zinc electroplated steel fibers immersed in simulated pore solution. Between the four experimental programs the most significant conclusion is that oxygen, moisture, and chlorides past the chloride threshold must be present for corrosion to propagate significantly on the zinc electroplated steel fibers.
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Date Issued
2016
PURL
http://purl.flvc.org/fau/fd/FA00004637, http://purl.flvc.org/fau/fd/FA00004637
Subject Headings
Fiber-reinforced concrete--Cracking., Cement composites., Reinforced concrete construction., Reinforced concrete--Corrosion., Corrosion and anti-corrosives., Structural engineering.
Format
Document (PDF)