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Title: Strength and Modulus of Recycled Aggregate Concrete Subjected to Wetting and Drying Cycles.
Creator: Alawadi, Farah, Sobhan, Khaled, Florida Atlantic University, College of Engineering and Computer Science, Department of Civil, Environmental and Geomatics Engineering
Abstract/Description: The reuse of crushed aggregates for producing structural concrete is a major concern especially when it comes to its strength and durability. This study evaluated recycled aggregate concrete (RAC) for its strength and durability under simulated environmental degradation in the form of wetting-drying (W-D) cycles. The study consisted of two phases, each involving the determination of the compressive strength and modulus of elasticity using the conventional method and also a nondestructive...
Show moreThe reuse of crushed aggregates for producing structural concrete is a major concern especially when it comes to its strength and durability. This study evaluated recycled aggregate concrete (RAC) for its strength and durability under simulated environmental degradation in the form of wetting-drying (W-D) cycles. The study consisted of two phases, each involving the determination of the compressive strength and modulus of elasticity using the conventional method and also a nondestructive ultrasonic pulse velocity method (Pundit Lab). Phase 1 involved 7-day curing followed by 30 W-D cycles, while Phase 2 included 28-day cured samples subjected to 15 W-D cycles. It was found that RAC specimens subjected to W-D cycles had minimal degradation in strength, making the use of RAC in construction very promising. Results from Pundit Lab compared reasonably well with conventional test results, showing promise as a nondestructive tool for the evaluation of RAC properties.
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Date Issued: 2018
PURL: http://purl.flvc.org/fau/fd/FA00013162
Subject Headings: Concrete, Durability of concrete, Strength of materials, Recycled aggregate concrete
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: Corrosion Propagation of Reinforcing Steel Embedded in Binary and Ternary Concrete.
Creator: Hoque, Kazi Naimul, Presuel-Moreno, Francisco, Florida Atlantic University, Department of Ocean and Mechanical Engineering, College of Engineering and Computer Science
Abstract/Description: The Florida Department of Transportation (FDOT) has been using supplementary cementitious materials while constructing steel reinforced concrete marine bridge structures for over three decades. It has been found from previous studies that such additions in concrete mix makes the concrete more durable. This research was conducted to better understand the corrosion propagation stage of steel rebar embedded in high performance concrete exposed to high humidity environment. Reinforced concrete...
Show moreThe Florida Department of Transportation (FDOT) has been using supplementary cementitious materials while constructing steel reinforced concrete marine bridge structures for over three decades. It has been found from previous studies that such additions in concrete mix makes the concrete more durable. This research was conducted to better understand the corrosion propagation stage of steel rebar embedded in high performance concrete exposed to high humidity environment. Reinforced concrete samples that were made with binary mixes, and ternary mixes were considered. None of these concretes had any admixed chloride to start with. An accelerated chloride transport method was used to drive chloride ions into the concrete so that chlorides reached and exceed the chloride threshold at the rebar surface and hence the corrosion process initiated after a short period of time (within few days to few months). Once corrosion has initiated the corrosion propagation can be studied. Electrochemical measurements such as rebar potential measurements, Linear Polarization Resistance (LPR), Electrochemical Impedance Spectroscopy (EIS), and Galvanostatic Pulse (GP) measurements were taken at regular intervals (during and after the electro-migration process) to observe the corrosion propagation in each sample. During the propagation stage, reinforcement eventually reached negative potentials values (i.e., Ecorr≤ –0.200 Vsce) for all the samples. The corrected polarization resistance (Rc) was calculated by subtracting the concrete solution resistance from the apparent polarization resistance measured. The Rc values obtained from LPR and GP measurements were converted to corrosion current (as the corroding area is unknown), and these corrosion current values measured over time were used to obtain the calculated mass loss (using Faraday’s Law). A comparison was made of the calculated corrosion current obtained using the LPR and GP tests. A comparison of mass loss was also obtained from the values measured from LPR and GP tests. From the experimental results, it was observed that the corrosion current values were largely dependent on the length of solution reservoirs. For specimens cast with single rebar as well as three rebars, the most recent corrosion current values (measurements taken between July 2018 to October 2020) in general were larger for the rebars that are embedded in specimens prepared with SL mix, followed by specimens prepared with FA, T1, and T2 mixes respectively. The range of corrosion current values (most recent) were 0.8-33.8 μA for SL samples, 0.5-22.5 μA for FA samples, 0.8-14.8 μA for T1 samples, and 0.7-10.4 μA for T2 samples respectively. It was also found that the calculated mass loss values were larger for rebars that are embedded in specimens (single rebar and three rebars) prepared with SL mix, followed by specimens prepared with FA, T1, and T2 mixes respectively. The range of calculated mass loss values were 0.07-1.13 grams for SL samples, 0.06-0.62 grams for FA samples, 0.12-0.54 grams for T1 samples, and 0.06-0.40 grams for T2 samples respectively. A variety of corrosion related parameters (Ecorr, Rs, Rc, and Icorr) and calculated theoretical mass loss values observed, were due to the changing parameters such as concrete compositions, concrete cover thickness, rebar diameter, total ampere-hour applied, and reservoir size. The specimens showed no visual signs of corrosion such as cracks or corrosion products that reached the concrete surface. The actual size of the corroding sites was unknown as the specimens were not terminated for forensic analysis. The size of the corroding sites could affect how much corrosion products are required to crack the concrete. It is speculated that the corrosion products in liquid form penetrated the pore structure but did not build up enough to cause cracks. No cracks or corrosion bleed outs were observed within the monitored propagation period of approximately 1600 days.
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Date Issued: 2020
PURL: http://purl.flvc.org/fau/fd/FA00013634
Subject Headings: Concrete, Concrete bridges--Corrosion, Carbon steel
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: Analysis of blast/explosion resistant reinforced concrete solid slab and T-Beam bridges.
Creator: Abdelahad, Firas A., Florida Atlantic University, College of Engineering and Computer Science, Department of Civil, Environmental and Geomatics Engineering
Abstract/Description: This study presents and illustrates a methodology to calculate the capacity of an existing reinforced concrete bridge under a non-conventional blast load due to low and intermediate pressures. ATBlast program is used to calculate the blast loads for known values of charge weight and stand off distance. An excel spreadsheet is generated to calculate ultimate resistance, equivalent elastic stiffness, equivalent elastic deflection, natural period of the beam, the maximum deflection, and the...
Show moreThis study presents and illustrates a methodology to calculate the capacity of an existing reinforced concrete bridge under a non-conventional blast load due to low and intermediate pressures. ATBlast program is used to calculate the blast loads for known values of charge weight and stand off distance. An excel spreadsheet is generated to calculate ultimate resistance, equivalent elastic stiffness, equivalent elastic deflection, natural period of the beam, the maximum deflection, and the maximum rotation in the support for a simple span solid slab and T-Beam bridges. The allowable rotation could be taken as to two degrees. Naval Facility Engineering Command (NAVFAC) approach was adopted, where the inputs were material properties, span length, and area of reinforcement. The use of the Fiber Reinforced Polymer for increasing the capacity of an existing bridge is also presented in this study. Parametric studies were carried out to evaluate the performance of the solid slab and T-Beam bridges under the assumed blast load.
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Date Issued: 2008
PURL: http://purl.flvc.org/fcla/flaent/EN00154040/68_1/98p0132d.pdf, http://purl.flvc.org/FAU/58001
Subject Headings: Concrete beams, Vibration, Bridges, Concrete, Fatigue, Reinforced concrete construction, Bridges, Concrete, Design and construction
Format: Document (PDF)

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: 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: 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: 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: Bulk diffusion of mature high performance concrete.
Creator: Arias, Wendy J., Presuel-Moreno, Francisco
Date Issued: 2013-04-05
PURL: http://purl.flvc.org/fcla/dt/3361064
Subject Headings: High performance concrete, High strength concrete, Bulk diffusion
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: Chloride Diffusivity and Aging Factor Determined on Field Simulated Concrete Exposed to Seawater.
Creator: Raof, Farhad Fakheri, Presuel-Moreno, Francisco, Florida Atlantic University, College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: Chloride diffusivity in high performance concrete is influenced by the exposure environment, aside from the concrete mixture properties like, water to cementitious ratio (w/cm) and presence of add-on pozzolans. In this study, a set of concrete specimens (eleven-different concrete mixtures) were cast and exposed to three different environmental conditions (Tidal, Splash and Barge) in which the solution was seawater or brackish water. These exposures simulated environmental field conditions....
Show moreChloride diffusivity in high performance concrete is influenced by the exposure environment, aside from the concrete mixture properties like, water to cementitious ratio (w/cm) and presence of add-on pozzolans. In this study, a set of concrete specimens (eleven-different concrete mixtures) were cast and exposed to three different environmental conditions (Tidal, Splash and Barge) in which the solution was seawater or brackish water. These exposures simulated environmental field conditions. After the specimens had been wet cured for 32 days (on average), the specimens were exposed to three different field simulation conditions for up to 54 months. The specimens under the field simulated conditions were cored at 6, 10, 18, 30 and 54 months at four elevations and then the chloride profiles were obtained from the cores. The apparent diffusivity values for each profile were calculated based on Fick’s 2nd law. Then, the aging factor “m” was calculated by regression analysis of the diffusivity values vs. time (days) plotted in the log10-log10 scale. This was done for samples exposed to the three different exposure conditions and then the results were compared side-by-side. First, the “m” values were calculated using the exposure duration. Then, to study the effect of including the curing time on “m” value, the curing time was added to the exposure time and a new calculation and “m” value was obtained and compared with the previous results. Moreover, upon inspecting the chloride diffusivity values vs. time plots, it was observed that in some cases, a number of data points showed significantly higher or lower values in comparison with the rest of the data points. It was decided to recalculate the “m” values for these cases, and to only use selected data points instead of all data points (i.e., remove outlier data points). In terms of chloride diffusivity value, it was found that in most cases the specimens with higher water to cementitious (w/cm) ratio showed higher diffusivity, as expected. Further, the presence of pozzolans had a noticeable impact on the chloride diffusivity by decreasing the diffusion rate due to microstructure changes that occurred with time. In terms of “m” values, the result for the field simulated conditions showed a range of “m” values dependent on the specimen’s mixture composition and the elevation at which the specimens were cored. It was observed that the chloride diffusivity declined with time and after a certain amount of time (in this research, almost after 30 months) the diffusivity reduction became small and a transition in the slope of the diffusivity trend appeared in a number of cases. After the transition, the diffusivity trend reached either a plateau zone or continued with a significantly lower slope, depending on the time, composition and exposure. It was found that the specimens under tidal and splash field simulation conditions that had only fly ash in their mixtures showed higher “m” values when compared with samples that contained fly ash and silica fume or fifty percent slag.
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Date Issued: 2019
PURL: http://purl.flvc.org/fau/fd/FA00013254
Subject Headings: Concrete--Environmental testing, Seawater, Chlorides, Diffusion, Concrete--Deterioration
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.
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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)

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: Microbial Induced Degradation in Synthetic Fiber Reinforced Concrete Samples in South Florida.
Creator: Parkinson, Jacqueline Cecile, Presuel-Moreno, Francisco, Florida Atlantic University, College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: Synthetic fiber reinforced concrete sample sets were exposed to two different environments. One set, of six samples, was exposed to filtered seawater in the lab with wet and dry cycles, while the other set of samples was exposed, on a barge, to the marine environment, in the intracoastal waterways, at SeaTech. The samples were exposed for 8 months, and then removed for experimental and mechanical testing. Upon removal, the barge samples were photographed to observe surface organisms that were...
Show moreSynthetic fiber reinforced concrete sample sets were exposed to two different environments. One set, of six samples, was exposed to filtered seawater in the lab with wet and dry cycles, while the other set of samples was exposed, on a barge, to the marine environment, in the intracoastal waterways, at SeaTech. The samples were exposed for 8 months, and then removed for experimental and mechanical testing. Upon removal, the barge samples were photographed to observe surface organisms that were attached to each sample. The barge samples, after cleaning, were then exposed to UV light to observe surface bacteria. The barge samples were also taken to Harbor Branch facility for DNA testing, and then sent in for sequencing. This sequencing was used to identify the organisms that were present inside the concrete samples. An Indirect Tensile Strength Test, IDT, was performed on both sets of samples to observe the first crack, max load, and fracture toughness of each sample. The Barge samples had a lower first crack, max load, and fracture toughness, which means that it took less force to break these samples, than the Seawater samples. As the fiber content increased, the Seawater samples grew stronger, while the Barge samples grew weaker. Also, as the fiber content increased, the biodiversity found on the surface of the Barge samples increased as well.
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Date Issued: 2019
PURL: http://purl.flvc.org/fau/fd/FA00013251
Subject Headings: Fiber-reinforced concrete, Florida, Concrete--Deterioration, Microbes
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: 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.
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Date Issued: 2003
PURL: http://purl.flvc.org/fcla/dt/13062
Subject Headings: Concrete piling, Reinforced concrete--Corrosion, Seawater corrosion
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)

FAU Theses and Dissertations (134)	+ -
FAU Graduate Student Research (1)	+ -
FAU Undergraduate Student Research (1)	+ -

Reinforced concrete (19)	+ -
Reinforced concrete--Corrosion (17)	+ -
Concrete (14)	+ -
Fiber reinforced plastics (13)	+ -
Steel--Corrosion (11)	+ -

Corrosion (10)	+ -
Reinforced concrete construction (10)	+ -
Testing (9)	+ -
Cathodic protection (8)	+ -
Concrete--Corrosion (6)	+ -
Corrosion and anti-corrosives (6)	+ -
Prestressed concrete construction (6)	+ -
Reinforced concrete, Fiber (6)	+ -
Acoustic emission testing (5)	+ -
Chlorides (5)	+ -
Concrete construction (5)	+ -
Concrete--Environmental testing (5)	+ -
Fly ash (5)	+ -
Fracture mechanics (5)	+ -
Reinforced concrete--Cracking (5)	+ -
Seawater corrosion (5)	+ -
Composite reinforced concrete (4)	+ -
Concrete piling (4)	+ -
Concrete--Deterioration (4)	+ -
High strength concrete (4)	+ -
Prestressed concrete (4)	+ -
Additives (3)	+ -
Bridges, Box girder (3)	+ -
Bridges, Concrete (3)	+ -
Carbon steel (3)	+ -

Florida (1)	+ -
Palm Beach County (1)	+ -

Electronic Thesis or Dissertation (134)	+ -
abstract (1)	+ -
poster (1)	+ -

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