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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.
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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.
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Date Issued: 1986
PURL: http://purl.flvc.org/fcla/dt/14310
Subject Headings: Reinforced concrete--Corrosion
Format: Document (PDF)

Title: Driveability of concrete piles pretensioned with CFRP and confinement effects of CFRP hoops in reinforced concrete columns.
Creator: Potturu, Rama Kumar., Florida Atlantic University, Arockiasamy, Madasamy, College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: Carbon Fiber Reinforced Plastics has recently has been recognized as an alternative to conventional steel reinforcement in concrete due to its excellent resistance to corrosion. Four rectangular concrete beams and four concrete columns reinforced with CFRP bars were cast for the study of the long term behavior under uniform sustained loading. The beams were simply supported and subjected to uniform sustained loading. The columns were arranged in a steel reaction framework. The beams and...
Show moreCarbon Fiber Reinforced Plastics has recently has been recognized as an alternative to conventional steel reinforcement in concrete due to its excellent resistance to corrosion. Four rectangular concrete beams and four concrete columns reinforced with CFRP bars were cast for the study of the long term behavior under uniform sustained loading. The beams were simply supported and subjected to uniform sustained loading. The columns were arranged in a steel reaction framework. The beams and columns were instrumented and monitored to observe the change in the behavior due to the creep and shrinkage of concrete. An analytical method is developed to predict the long term behavior of CFRP reinforced concrete members. The calculated deformations compare reasonably with the experimental values. A modified equation for the calculation of the long term deflection is proposed for CFRP reinforced concrete beams. A simplified equation for the calculation of the creep coefficient is also proposed.
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Date Issued: 1997
PURL: http://purl.flvc.org/fcla/dt/15507
Subject Headings: Fiber reinforced plastics, Concrete piling, Reinforced concrete, Columns, Concrete
Format: Document (PDF)

Title: Driveability of concrete piles pretensioned with CFRP.
Creator: Gemmell, Thomas Scott., Florida Atlantic University, Arockiasamy, Madasamy
Abstract/Description: Four concrete piles prestressed with Carbon Fiber Reinforced Plastics were cast, in which two piles were fabricated with CFRP transverse reinforcement. The remaining two were provided with transverse steel spiral reinforcement. The piles were designed according to Florida Department of Transportation (FDOT) guidelines. The Pile Driving Analyzer (PDA) was chosen as the primary data acquisition system for the pile driving due to its mobility, reliability and robustness based on the high...
Show moreFour concrete piles prestressed with Carbon Fiber Reinforced Plastics were cast, in which two piles were fabricated with CFRP transverse reinforcement. The remaining two were provided with transverse steel spiral reinforcement. The piles were designed according to Florida Department of Transportation (FDOT) guidelines. The Pile Driving Analyzer (PDA) was chosen as the primary data acquisition system for the pile driving due to its mobility, reliability and robustness based on the high frequency excitation. The Pre-driving analysis consisted of several stages. The estimated static bearing capacity of the experimental piles was first calculated followed by SPT sampling at the pile driving site to obtain the soil conditions. The percent skin and toe friction, ultimate capacities, driving system parameters, maximum displacements, energy, integrity, tensions and static capacity were determined prior to pile driving. The piles were then driven and the data from the pile driving compared with the analysis.
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Date Issued: 1997
PURL: http://purl.flvc.org/fcla/dt/15496
Subject Headings: Concrete piling, Fiber reinforced plastics, Prestressed concrete
Format: Document (PDF)

Title: Time-dependent behavior of reinforced concrete members with carbon fiber reinforced plastics (CFRP) under sustained loads.
Creator: Chidambaram, Senthilkumar., Florida Atlantic University, Arockiasamy, Madasamy
Abstract/Description: Carbon Fiber Reinforced Plastics has recently has been recognized as an alternative to conventional steel reinforcement in concrete due to its excellent resistance to corrosion. Four rectangular concrete beams and four concrete columns reinforced with CFRP bars were cast for the study of the long term behavior under uniform sustained loading. The beams were simply supported and subjected to uniform sustained loading. The columns were arranged in a steel reaction framework. The beams and...
Show moreCarbon Fiber Reinforced Plastics has recently has been recognized as an alternative to conventional steel reinforcement in concrete due to its excellent resistance to corrosion. Four rectangular concrete beams and four concrete columns reinforced with CFRP bars were cast for the study of the long term behavior under uniform sustained loading. The beams were simply supported and subjected to uniform sustained loading. The columns were arranged in a steel reaction framework. The beams and columns were instrumented and monitored to observe the change in the behavior due to the creep and shrinkage of concrete. An analytical method is developed to predict the long term behavior of CFRP reinforced concrete members. The calculated deformations compare reasonably with the experimental values. A modified equation for the calculation of the long term deflection is proposed for CFRP reinforced concrete beams. A simplified equation for the calculation of the creep coefficient is also proposed.
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Date Issued: 1997
PURL: http://purl.flvc.org/fcla/dt/15424
Subject Headings: Fiber reinforced plastics, Columns, Concrete, Concrete beams
Format: Document (PDF)

Title: Effects of cement alkalinity, exposure conditions and steel-concrete interface on the time-to-corrosion and chloride threshold for reinforcing steel in concrete.
Creator: Nam, Jingak., Florida Atlantic University, Hartt, William H., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: Effects of (1) cement alkalinity (low, normal and high), (2) exposure conditions (RH and temperature), (3) rebar surface condition (as-received versus cleaned) and (4) density and distribution of air voids at the steel-concrete interface on the chloride threshold and time-to-corrosion for reinforcing steel in concrete have been studied. Also, experiments were performed to evaluate effects of RH and temperature on the diffusion of chloride in concrete and develop a method for ex-situ pH...
Show moreEffects of (1) cement alkalinity (low, normal and high), (2) exposure conditions (RH and temperature), (3) rebar surface condition (as-received versus cleaned) and (4) density and distribution of air voids at the steel-concrete interface on the chloride threshold and time-to-corrosion for reinforcing steel in concrete have been studied. Also, experiments were performed to evaluate effects of RH and temperature on the diffusion of chloride in concrete and develop a method for ex-situ pH measurement of concrete pore water. Once specimens were fabricated and exposed to a corrosive chloride solution, various experimental techniques were employed to determine time-to-corrosion, chloride threshold, diffusion coefficient and void density along the rebar trace as well as pore water pH. Based upon the resultant data, several findings related to the above parameters have been obtained as summarized below. First, time for the corrosion initiation was longest for G109 concrete specimens with high alkalinity cement (HA). Also, chloride threshold increased with increasing time-to-corrosion and cement alkalinity. Consequently, the HA specimens exhibited the highest chloride threshold compared to low and normal alkalinity ones. Second, high temperature and temperature variations reduced time-to-corrosion of reinforcing steel in concrete since chloride diffusion was accelerated at higher temperature and possibly by temperature variations. The lowest chloride threshold values were found for outdoor exposed specimens suggesting that variation of RH or temperature (or both) facilitated rapid chloride diffusion. Third, an elevated time-to-corrosion and chloride threshold values were found for the wire brushed steel specimens compared to as-received ones. The higher ratio of [OH-]/[Fe n+] on the wire brushed steel surface compared to that of as-received case can be the possible cause because the higher ratio of this parameter enables the formation of a more protective passive film on the rebar. Fourth, voids at the steel-concrete interface facilitated passive film breakdown and onset of localized corrosion. This tendency for corrosion initiation increased in proportion to void size irrespective of specimen type. Also, [Cl -]th decreased with increasing void diameter. In addition, new ex-situ leaching method for determining concrete pore water alkalinity was developed.
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Date Issued: 2004
PURL: http://purl.flvc.org/fcla/dt/12096
Subject Headings: Reinforced concrete construction, Chlorides, Steel--Corrosion, Composite reinforced concrete
Format: Document (PDF)

Title: Experiments and modeling on resistivity of multi-layer concrete with and without embedded rebar.
Creator: Liu, Yanbo., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: Factors such as water to cement ratio, moisture, mixture, presence and depth of rebar, and dimension of specimens, all of which affect apparent resistivity of concrete, were analyzed by experimental and modeling methods. Cylinder and rectangular prism concrete specimens were used in the experiments exposed in a high moisture room, laboratory room temperature, high humidity and outdoor weather environments. Single rebar and four rebar specimens were used to study the rebar effect on the...
Show moreFactors such as water to cement ratio, moisture, mixture, presence and depth of rebar, and dimension of specimens, all of which affect apparent resistivity of concrete, were analyzed by experimental and modeling methods. Cylinder and rectangular prism concrete specimens were used in the experiments exposed in a high moisture room, laboratory room temperature, high humidity and outdoor weather environments. Single rebar and four rebar specimens were used to study the rebar effect on the apparent resistivity. Modeling analysis was employed to verify and explain the experimental results. Based on the results, concrete with fly ash showed higher resistivity than concrete with just ordinary Portland cement. Rebar presence had a significant effect on the measured apparent resistivity at some of the locations. The results could be used as a guide for field apparent resistivity measurements and provide a quick, more precise and easy way to estimate the concrete quality.
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Date Issued: 2008
PURL: http://purl.flvc.org/FAU/166452
Subject Headings: Reinforced concrete, Corrosion, Testing, Reinforcing bars, Properties, Concrete, Quality control
Format: Document (PDF)

Title: Synthetic Fiber Reinforced Concrete in Marine Environments and Indirect Tension Test.
Creator: Flaherty, Ryan, Presuel-Moreno, Francisco, Florida Atlantic University, College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: An experiment was conducted to evaluate the durability, toughness, and strength of Synthetic Fiber Reinforced Concrete after being immersed in five separate environments for one year at FAU SeaTech. The specimens were molded and reinforced with two-inch Polypropylene/Polyethylene Fibers in a concrete aggregate matrix and were cut into identical sizes. Some of these environments had accelerated parameters meant to increase degradation to simulate longevity and imitate harsh environments or...
Show moreAn experiment was conducted to evaluate the durability, toughness, and strength of Synthetic Fiber Reinforced Concrete after being immersed in five separate environments for one year at FAU SeaTech. The specimens were molded and reinforced with two-inch Polypropylene/Polyethylene Fibers in a concrete aggregate matrix and were cut into identical sizes. Some of these environments had accelerated parameters meant to increase degradation to simulate longevity and imitate harsh environments or seawater conditions. The environments consisted of: a high humidity locker (ideal conditions), submerged in the Intracoastal Waterway (FAU barge), seawater immersion, a wet and dry seawater immersion simulating a splash/tidal zone, and another in low pH seawater. The latter three were in an elevated temperature room (87-95°F) which produced more degradative properties. The specimens were monitored and the environments were controlled. The specimens were then evaluated using the IDT test method using force to initiate first-cracking and post-cracking behaviors.
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Date Issued: 2018
PURL: http://purl.flvc.org/fau/fd/FA00013029
Subject Headings: Reinforced concrete, Fiber-reinforced concrete--Testing, Synthetic fibers
Format: Document (PDF)

Title: Behavior of eccentrically loaded slender concrete columns reinforced with CFRP bars.
Creator: Xia, Wei., Florida Atlantic University, Arockiasamy, Madasamy, College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: In a highly corrosive environment, corrosion is the main factor leading to deterioration and eventual failure of conventional reinforced or prestressed concrete structures. Carbon Fiber Reinforced Plastics (CFRP) are considered as an alternative to steel reinforcement due to its excellent corrosion resistance. This investigation was conducted to establish the feasibility of using CFRP cables as reinforcing elements in reinforced concrete columns. Besides investigating durability of CFRP...
Show moreIn a highly corrosive environment, corrosion is the main factor leading to deterioration and eventual failure of conventional reinforced or prestressed concrete structures. Carbon Fiber Reinforced Plastics (CFRP) are considered as an alternative to steel reinforcement due to its excellent corrosion resistance. This investigation was conducted to establish the feasibility of using CFRP cables as reinforcing elements in reinforced concrete columns. Besides investigating durability of CFRP cables in adverse environments (alkali and sea water) experimental and theoretical studies were carried out to study the behavior of CFRP reinforced concrete slender columns under combined axial load and bending moment. Exposure to air, sea water and alkali environments with alternating wet/dry cycles had no adverse effect on the strength of the CFRP cables. The CFRP reinforced concrete columns subjected to eccentric loads exhibited excellent ultimate load capacity. Feasibility of using CFRP cables in the reinforced concrete columns is assessed based on deflections, strains, curvatures, crack distributions, first crack loads and ultimate loads.
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Date Issued: 1997
PURL: http://purl.flvc.org/fcla/dt/15426
Subject Headings: Reinforced concrete, Columns, Concrete, Fiber reinforced plastics, Eccentric loads
Format: Document (PDF)

Title: Corrosion propagation of dry-cast reinforced concrete pipes after initiation.
Creator: Balasubramanian, Hariharan, Graduate College
Date Issued: 2013-04-12
PURL: http://purl.flvc.org/fcla/dt/3361269
Subject Headings: Reinforced concrete, Corrosion, Drainage pipes
Format: Document (PDF)

Title: INITIATION AND PROPAGATION OF CORROSION IN DRY-CAST REINFORCED CONCRETE PIPES WITH ENVIRONMENTAL EFFECTS.
Creator: Balasubramanian, Hariharan, Presuel-Moreno, Francisco, Florida Atlantic University, College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: This research was conducted to better understand the corrosion propagation stage on dry-cast reinforced concrete pipes (DCRCPs) while exposed to high moisture conditions and chlorides. Corrosion initiation and propagation were studied in instrumented specimens obtained from segments of dry-cast reinforced concrete pipes. All specimens were subjected to accelerated chloride transport by the application of an electric field. Corrosion of the steel wire mesh initiated after a few days to a few...
Show moreThis research was conducted to better understand the corrosion propagation stage on dry-cast reinforced concrete pipes (DCRCPs) while exposed to high moisture conditions and chlorides. Corrosion initiation and propagation were studied in instrumented specimens obtained from segments of dry-cast reinforced concrete pipes. All specimens were subjected to accelerated chloride transport by the application of an electric field. Corrosion of the steel wire mesh initiated after a few days to a few months rather than several years. The specimens were then transferred to high moisture environments (immersed in water, high humidity and/or covered with wet sand) during the corrosion propagation stage. Reinforcement potentials, linear polarization resistance (LPR) and Electrochemical Impedance Spectroscopy (EIS) measurements were carried out periodically. During the propagation stage in different exposures, reinforcement eventually reached negative potentials values (< –-0.55 Vsce), which suggest mass transfer limitations. These specimens showed no visual signs of corrosion such as cracks or corrosion products except the ones exposed to high humidity and laboratory environments; where some corrosion products have reached the concrete surface. Moreover, the apparent corrosion rate values obtained suggest high corrosion rates. No crack appearance on specimens exposed to other conditions could be explained by the porosity of the specimens; the corrosion products moved into saturated pores. It is speculated that although there might be mass transfer limitations present, the current demanded by the anode is being balanced by a larger cathode area due to macrocell effects since the high moisture conditions likely reduced the concrete resistivity and increased the throwing power. The corrected polarization resistance (Rc) was calculated by subtracting the solution resistance from the apparent polarization resistance measured. The Rc values measured over time were used to obtain the calculated mass loss (using Faraday’s Law). Most specimens were forensically analyzed and the measured mass loss compared to the calculated mass loss. The forensic examination includes the measurement of the actual corroding areas. The measured corroding areas were used to obtain corrosion current density (icorr) values. A comparison was made of the calculated corrosion current densities obtained using the linear polarization resistance method (LPR) and the extrapolation method from cyclic polarization tests. It was evident that most of the specimens’ corrosion rates were significantly high. The corrosion products filled the wet-pores inside the concrete and provide an explanation for no cracks or corrosion bleed outs being visually observed on the specimens.
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Date Issued: 2019
PURL: http://purl.flvc.org/fau/fd/FA00013182
Subject Headings: Reinforced concrete, Corrosion, Environmental effects
Format: Document (PDF)

Title: CORROSION OF STEEL REINFORCEMENT IN CONCRETE: THRESHOLD CHLORIDE ION CONCENTRATION FOR CORROSION IN TYPE I PORTLAND CEMENT CONCRETE.
Creator: FUNAHASHI, MIKI., Florida Atlantic University, Hartt, William H.
Abstract/Description: Initiation of corrosion of reinforcing steel in concrete is often caused by chlorides. Using a pressurized method for the purpose of accelerating penetration of sea water into concrete, the threshold chloride ion concentration for corrosion of reinforcing steel in Type I portland cement concrete has been studied in detail. The variables that have been investigated include water-cement ratio and steel surface preparation. When corrosion was detected by electrochemical potential measurement,...
Show moreInitiation of corrosion of reinforcing steel in concrete is often caused by chlorides. Using a pressurized method for the purpose of accelerating penetration of sea water into concrete, the threshold chloride ion concentration for corrosion of reinforcing steel in Type I portland cement concrete has been studied in detail. The variables that have been investigated include water-cement ratio and steel surface preparation. When corrosion was detected by electrochemical potential measurement, the test was terminated; and chloride ion concentration was evaluated. No correlation between threshold concentration and water-cement ratio was found. With regard to surface condition, the pre-rusted steel specimen showed a tendency to corrode at a lesser chloride ion concentration than for the other preparation techniques, which were sand blasting and pretreatment in a saturated calcium hydroxide solution. The results are presented and discussed within a perspective of established concrete and corrosion technologies.
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Date Issued: 1985
PURL: http://purl.flvc.org/fcla/dt/14264
Subject Headings: Steel--Corrosion, Reinforced concrete
Format: Document (PDF)

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)

Title: FRACTURE MECHANICS OF FIBER REINFORCED CONCRETE AND THE DURABILITY OF FIBER REINFORCED AND AIR-ENTRAINED CONCRETE EXPOSED TO FREEZE-THAW CYCLES (FATIGUE).
Creator: JEANFREAU, JAMES JOSEPH, JR., Florida Atlantic University, Arockiasamy, Madasamy
Abstract/Description: This thesis presents the experimental and analytical investigation of fiber (steel and Kevlar) reinforced concrete (FRC) to determine its fracture mechanic properties especially the J-integral. The freeze-thaw durability of fiber reinforced and air-entrained concrete is also investigated. The fiber reinforced concretes were found to have a much greater flexural strength and toughness compared to plain concrete. The compressive strength was found to decrease with the addition of fibers and air...
Show moreThis thesis presents the experimental and analytical investigation of fiber (steel and Kevlar) reinforced concrete (FRC) to determine its fracture mechanic properties especially the J-integral. The freeze-thaw durability of fiber reinforced and air-entrained concrete is also investigated. The fiber reinforced concretes were found to have a much greater flexural strength and toughness compared to plain concrete. The compressive strength was found to decrease with the addition of fibers and air-entrainment. In all cases the addition of 1.0% or more fibers prevented catastrophic failures. The mixing and setting of FRC requires a rigorous procedure which must be followed to achieve a homogeneous matrix.
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Date Issued: 1986
PURL: http://purl.flvc.org/fcla/dt/14334
Subject Headings: Reinforced concrete, Fiber, Fracture mechanics
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.
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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: Experimental studies on flexural behavior of CFRP retrofitted concrete members.
Creator: Raghavachary, Sowrirajan., Florida Atlantic University, Arockiasamy, Madasamy, College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: The flexural behavior of rectangular concrete beams strengthened with externally bonded Carbon Fiber Reinforced Plastic (CFRP) laminates was studied by varying the number of plates bonded to their bottom tensile face. The increases in strength and stiffness of the beams provided by the bonded plates, over control beam without CFRP plates, were evaluated. Failure loads of the beams were determined by the ACI strain compatibility method using a FORTRAN software developed for this purpose. The...
Show moreThe flexural behavior of rectangular concrete beams strengthened with externally bonded Carbon Fiber Reinforced Plastic (CFRP) laminates was studied by varying the number of plates bonded to their bottom tensile face. The increases in strength and stiffness of the beams provided by the bonded plates, over control beam without CFRP plates, were evaluated. Failure loads of the beams were determined by the ACI strain compatibility method using a FORTRAN software developed for this purpose. The predicted collapsed load agrees reasonably well with the actual failure load. Precracked solid and voided slab bridge models retrofitted with varying number of CFRP laminates were used to evaluate their contribution to the flexural resistance. The increases in strength and stiffness of the retrofitted slabs were based on the deflections, strains and crack patterns at ultimate load. Theoretical analyses to predict the load-deflection behavior of the precracked sections were performed using PCFRAME software. The predicted values agree reasonably well with the experimental results.
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Date Issued: 1995
PURL: http://purl.flvc.org/fcla/dt/15120
Subject Headings: Fiber reinforced plastics, Reinforced concrete, Fiber, Bridges, Concrete, Prestressed concrete, Concrete beams--Fatigue
Format: Document (PDF)

Title: SYNTHETIC FIBER REINFORCED CONCRETE PERFORMANCE AFTER PROLONGED ENVIRONMENTAL EXPOSURE UTILIZING THE MODIFIED INDIRECT TENSILE TEST.
Creator: Ellis, Spencer G., Presuel-Moreno, Francisco, Florida Atlantic University, Department of Ocean and Mechanical Engineering, College of Engineering and Computer Science
Abstract/Description: In order to study the mechanical performance of dry-cast synthetic fiber reinforced concrete (SynFRC), samples of varying geometry, fiber content, and environmental exposure were developed and tested using the modified indirect tensile test. The samples created consisted of three different thicknesses (with two different geometries), and six different fiber contents that differed in either type, or quantity, of fibers. Throughout the duration of this research, procedures for inflicting...
Show moreIn order to study the mechanical performance of dry-cast synthetic fiber reinforced concrete (SynFRC), samples of varying geometry, fiber content, and environmental exposure were developed and tested using the modified indirect tensile test. The samples created consisted of three different thicknesses (with two different geometries), and six different fiber contents that differed in either type, or quantity, of fibers. Throughout the duration of this research, procedures for inflicting detrimental materials into the concrete samples were employed at a number of different environments by implementing accelerated rates of deterioration using geometric adjustments, increased temperature exposure, wetting/drying cycles, and preparation techniques. The SynFRC samples studied were immersed in a wide range of environments including: the exposure of samples to high humidity and calcium hydroxide environments, which served at the control group, while the sea water, low pH, and barge conditioning environments were used to depict the real world environments similar to what would be experienced in the Florida ecosystem. As a result of this conditioning regime, the concrete was able to imitate the real-world effects that the environments would have inflicted if exposed for long durations after an exposure period of only 20-24 months. Having adequately conditioned the samples in their respective environments, they were then tested (and forensically investigated) using the modified indirect tensile testing method to gather data regarding each sample’s toughness and load handling capability. By analyzing the results from each sample, the toughness was calculated by taking the area under the force displacement curve. From these toughness readings it was found that possible degradation occurred between the fiber-matrix interface of some of the concrete samples conditioned in the Barge environment. From these specimens that were immersed in the barge environment, a handful of them exhibited multiple episodes of strain softening characteristics within their force displacement curves. In regard to the fibers used within the samples, the PVA fibers tended to pull off more while the Tuff Strand SF fibers had the highest tendency to break (despite some of the fibers showing similar pull off and breaking failure characteristics). When it comes to the overall thickness of the sample, there was clear correlation between the increase in size and the increase in sample toughness, however the degree to which it correlates varies from sample to sample.
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Date Issued: 2020
PURL: http://purl.flvc.org/fau/fd/FA00013466
Subject Headings: Reinforced concrete, Fiber-reinforced concrete--Testing, Reinforced concrete--Mechanical properties, Tensile Strength, Concrete—Environmental testing
Format: Document (PDF)

Title: Concrete surface resistivity profiles along the splash zone on bridge piles exposed to sea water.
Creator: Suarez-Solano, Andres M., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: Prevention of the corrosion of steel reinforcement embedded in concrete is a constant challenge in engineering. A study of concrete surface resistivity versus elevation of partially immersed reinforced concrete structures in a marine splash zone has been developed and correlations made between concrete quality and chloride diffusion, i.e., aggressive ion permeability. A conditioning procedure was developed in which the concrete moisture content is increased by direct contact with fresh water...
Show morePrevention of the corrosion of steel reinforcement embedded in concrete is a constant challenge in engineering. A study of concrete surface resistivity versus elevation of partially immersed reinforced concrete structures in a marine splash zone has been developed and correlations made between concrete quality and chloride diffusion, i.e., aggressive ion permeability. A conditioning procedure was developed in which the concrete moisture content is increased by direct contact with fresh water for several days. The electrical resistivity of concrete is known to be primarily a function of the degree of water saturation. Correlations between field obtained concrete surface resistivity values versus chloride diffusivity, and between normalized resistivity measured on cores obtained from the field versus chloride diffusivity has been established. The resistivity values were measured on structures with different concrete mixes and various ages.
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Date Issued: 2009
PURL: http://purl.flvc.org/FAU/369390
Subject Headings: Reinforced concrete, Corrosion, Testing, Reinforcing bars, Properties, Concrete, Permeability, Concrete, Fluid dynamics
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.
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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.
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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)

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