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Accelerated curing of concrete with high volume pozzolans - resistivity, diffusivity and compressive strength
Title
Accelerated curing of concrete with high volume pozzolans - resistivity, diffusivity and compressive strength.
Creator
Liu, Yanbo., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description
This investigation presents results of the temperature effect on durability properties (resistivity and diffusivity) and compressive strength of concrete with pozzolans, and the effect of pozzolanic admixtures on microstructure and chemical compositions of concrete pore solution. ... Temperature dependence of electrical resistivity and chloride diffusivity was studied by dynamic temperature tests. Accelerated curing regimes involving curing concrete specimens in 35À C lime water with...
Show moreThis investigation presents results of the temperature effect on durability properties (resistivity and diffusivity) and compressive strength of concrete with pozzolans, and the effect of pozzolanic admixtures on microstructure and chemical compositions of concrete pore solution. ... Temperature dependence of electrical resistivity and chloride diffusivity was studied by dynamic temperature tests. Accelerated curing regimes involving curing concrete specimens in 35À C lime water with different durations were tested. Compressive strength test, resisivity measurement and rapid chloride migration (RCM) tests were performed. A leaching method was used to measure pH and conductivity of concrete pore solution. ... The accelerated curing regimes were found to increase the compressive strength and resistance to chloride ion penetration at short-term and long-term. With the developed correlation between resistivity and migration coefficients, it is possible to employ the resistivity measurement as an alternative or replacement of the RCM test to evaluate resistance of chloride ion penetration of concrete. Pozzolanic admixtures were found to decrease both pH and conductivity of concrete pore solution as the replacement ratio increased. Moreover, the migration coefficients were found to be greatly correlated to the microstructure properties of concrete, such as porosity, formation factor and tortuosity.
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Date Issued
2012
PURL
http://purl.flvc.org/FAU/3358603
Subject Headings
Pavements, Concrete, Additives, Quality control, Waste products as road materials, Reinforced concrete, Corrosion, Testing
Format
Document (PDF)
Concrete diffusivity and its correlation with chloride deposition rate on concrete exposed to marine environments
Title
Concrete diffusivity and its correlation with chloride deposition rate on concrete exposed to marine environments.
Creator
Echevarria, Victor Anthony., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description
The aim of this study was to investigate the diffusion of chloride ions into concrete samples that were exposed in scenarios that simulate the splash, tidal, atmospheric, and immersed portions of a marine structure. To study the atmospheric deposition, the project also investigated the relationship between chloride ion deposition on the wet candle and its accumulation into concrete samples. Results from the wet candle experiment indicated that between 2% and 45% of the chlorides deposited per...
Show moreThe aim of this study was to investigate the diffusion of chloride ions into concrete samples that were exposed in scenarios that simulate the splash, tidal, atmospheric, and immersed portions of a marine structure. To study the atmospheric deposition, the project also investigated the relationship between chloride ion deposition on the wet candle and its accumulation into concrete samples. Results from the wet candle experiment indicated that between 2% and 45% of the chlorides deposited per square meter of exposed area could be found within the concrete samples. After 6 months, slag G1a blocks showed the most resistance to chloride penetration in the tidal and splash simulations. After 10 months of exposure, fly ash samples had the slowest rates of diffusion in the tidal simulation while the fly ash + silica fume samples and the slag samples measured similar rates of diffusion within the tidal zone. After 90 days of curing, cylinders composed of 20% fly ash & 8% silica fume measured the highest average resistivity values and were found to be less vulnerable to chloride ion penetration than the 20% fly ash and the 50% slag concrete through rapid migration tests.
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Date Issued
2012
PURL
http://purl.flvc.org/FAU/3358557
Subject Headings
Reinforced concrete, Construction, Corrosion, Composite reinforced concrete, Corrosion, Testing, Concrete, Fluid dynamics, Concrete, Chemical resistance, Chlorides, Diffusion rate
Format
Document (PDF)
Concrete surface resistivity profiles along the splash zone on bridge piles exposed to sea water
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)
Corrosion initiation and propagation on corrosion resistant alloys embedded in concrete by accelerated chloride transport
Title
Corrosion initiation and propagation on corrosion resistant alloys embedded in concrete by accelerated chloride transport.
Creator
Gutierrez Tellez, Francisco., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description
Two duplex stainless steels rebars: UNS32304SS and UNS32101SS, were selected to investigate the corrosion initiation and propagation in reinforced concrete specimens. The investigation is divided in two phases with two different methods to accelerate the transport of chlorides through the concrete and initiate corrosion in a short period of time. After corrosion had initiated and propagated for some time; selected specimens were terminated for visual examination. On specimens selected for...
Show moreTwo duplex stainless steels rebars: UNS32304SS and UNS32101SS, were selected to investigate the corrosion initiation and propagation in reinforced concrete specimens. The investigation is divided in two phases with two different methods to accelerate the transport of chlorides through the concrete and initiate corrosion in a short period of time. After corrosion had initiated and propagated for some time; selected specimens were terminated for visual examination. On specimens selected for autopsy, the rebars in the top row showed corrosion to various degrees. Corrosion had propagated to such extent on the terminated specimens that the specimen showed cracks. Stray current might have caused accelerated corrosion on rebars where corrosion had initiated. Based on chloride concentrations measured at the rebar trace, corrosion initiated: on S32101 rebars on average at 7.9 kg/m3, and S32101 rebars on average at 6.0 kg/m3. The findings suggest that S32304 rebars corroded at a slower than S32101.
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Date Issued
2013
PURL
http://purl.flvc.org/fcla/dt/3362380
Subject Headings
Concrete, Corrosion, Concrete construction, Reinforced concrete, Chemical resistance, Steel, Structural, Corrosion
Format
Document (PDF)
Corrosion initiation on corrosion resistant alloys via acceleration chloride transport
Title
Corrosion initiation on corrosion resistant alloys via acceleration chloride transport.
Creator
Gutierrez, Francisco, Graduate College
Date Issued
2013-04-12
PURL
http://purl.flvc.org/fcla/dt/3361305
Subject Headings
Corrosion resistant alloys, Corrosion, Corrosion and anti-corrosives--Testing
Format
Document (PDF)
CORROSION MONITORING AND ANALYSIS OF REINFORCED CONCRETE: CORROSION RESISTANT ALLOYS AFTER LONG TERM EXPOSURE TO CHLORIDES
Title
CORROSION MONITORING AND ANALYSIS OF REINFORCED CONCRETE: CORROSION RESISTANT ALLOYS AFTER LONG TERM EXPOSURE TO CHLORIDES.
Creator
Taylor, Redmayne, Presuel-Moreno, Francisco, Florida Atlantic University, Department of Ocean and Mechanical Engineering, College of Engineering and Computer Science
Abstract/Description
Reinforced concrete (RC) is the building block of modern architecture and industry. The failure of which is costly and dangerous. Typically made with carbon steel rebars, corrosion resistant alloys provide an alternative method of delaying failure. Stainless steels, while more expensive than carbon steels, provide excellent corrosion resistance, but less is known about the long term monitoring of corrosion activity for stainless steel than for carbon steel. This study looks at samples...
Show moreReinforced concrete (RC) is the building block of modern architecture and industry. The failure of which is costly and dangerous. Typically made with carbon steel rebars, corrosion resistant alloys provide an alternative method of delaying failure. Stainless steels, while more expensive than carbon steels, provide excellent corrosion resistance, but less is known about the long term monitoring of corrosion activity for stainless steel than for carbon steel. This study looks at samples prepared between 2005 and 2009 using 304SS, 316SS, and 2304SS rebars, as well as SMI and Stelax stainless steel clad carbon steel reinforcements embedded in three different concrete mixes. These selected samples are split into two exposure environments, inside humidity chambers within the laboratory and outdoor exposure. Measurements reported here were made monthly over the course of 250 plus days using the Galvanostatic Pulse method, Electrochemical Impedance Spectroscopy, and a Gecor 8 device. These methods were used to determine corrosion current, isolated corrosion current density, and solution resistance. Corrosion current density values calculated from measurements by the Galvanostatic Pulse and Electrochemical Impedance Spectroscopy method are too small to indicate corrosion, based on value ranges provided by Andrade. However, Gecor 8 corrosion current density values indicate low levels or moderate levels of corrosion for all samples compared to the Andrade’s value ranges. The area used by the Gecor is unknown, so it’s possible this is driving up the measured values.
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Date Issued
2023
PURL
http://purl.flvc.org/fau/fd/FA00014258
Subject Headings
Reinforced concrete, Corrosion resistant alloys, Carbon steel, Corrosion
Format
Document (PDF)
Corrosion propagation of dry-cast reinforced concrete pipes after initiation
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)
Experimental evaluation of the durability of fly ash-based geopolymer concrete in the marine environment
Title
Experimental evaluation of the durability of fly ash-based geopolymer concrete in the marine environment.
Creator
Edouard, Jean-Baptiste., College of Engineering and Computer Science, Department of Civil, Environmental and Geomatics Engineering
Abstract/Description
The construction industry is increasingly turning to the use of environmentally friendly materials in order to meet the sustainable aspect required by modern infrastructures. Consequently, for the last two decades, the expansion of this concept, and the increasing global warming have raised concerns on the extensive use of Portland cement due to the high amount of carbon dioxide gas associated with its production. The development of geopolymer concretes offers promising signs for a change in...
Show moreThe construction industry is increasingly turning to the use of environmentally friendly materials in order to meet the sustainable aspect required by modern infrastructures. Consequently, for the last two decades, the expansion of this concept, and the increasing global warming have raised concerns on the extensive use of Portland cement due to the high amount of carbon dioxide gas associated with its production. The development of geopolymer concretes offers promising signs for a change in the way of producing concrete. However, to seriously consider geopolymer binders as an alternative to ordinary Portland cement, the durability of this new material should be evaluated in any comparative analysis. The main purpose of this study was to evaluate the durability characteristics of low calcium fly ash-based geopolymer concretes subjected to the marine environment, compared to ordinary Portland cement concrete with similar exposure. To achieve this goal, 8 molar geopolymer, 14 molar geopolymer and ordinary Portland cement concrete mixes were prepared and tested for exposure in seawater. Compressive strengths in the range of 2900 to 8700 psi (20-60 MPa) were obtained. The corrosion resistance performance of steel-reinforced concrete beams, made of these mixes, was also studied, using an accelerated electrochemical method, with submergence in salt water. The test results indicated that the geopolymer concrete showed excellent resistance to chloride attack, with longer time to corrosion cracking, compared to ordinary Portland cement concrete.
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Date Issued
2011
PURL
http://purl.flvc.org/FAU/3170960
Subject Headings
Reinforced concrete, Corrosion, Testing, Reinforced concrete construction, Concrete, Mixing, Quality control, Environmental chemistry, Industrial applications, Polymer composites
Format
Document (PDF)
Experiments and modeling on resistivity of multi-layer concrete with and without embedded rebar
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)
INITIATION AND PROPAGATION OF CORROSION IN DRY-CAST REINFORCED CONCRETE PIPES WITH ENVIRONMENTAL EFFECTS
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)
THE IMPACT CORROSION HAS ON THE DEGRADATION OF MECHANICAL PROPERTIES OF CARBON STEEL REBARS IN HIGH PERFORMANCE CONCRETE
Title
THE IMPACT CORROSION HAS ON THE DEGRADATION OF MECHANICAL PROPERTIES OF CARBON STEEL REBARS IN HIGH PERFORMANCE CONCRETE.
Creator
Rosa-Pagan, Angel R., Presuel-Moreno, Francisco, Florida Atlantic University, Department of Ocean and Mechanical Engineering, College of Engineering and Computer Science
Abstract/Description
A significant amount of reinforced concrete structures in the USA are reaching the design life span of 50 years. Degradation of these infrastructure due to corrosion presents an economical, safety and quality of life challenge for our society. Being able to study and determine the conditions of our infrastructure, perform maintenance before failure and predict failure before occurrence has become critical for our society and our way of life. This study was performed to add to existing...
Show moreA significant amount of reinforced concrete structures in the USA are reaching the design life span of 50 years. Degradation of these infrastructure due to corrosion presents an economical, safety and quality of life challenge for our society. Being able to study and determine the conditions of our infrastructure, perform maintenance before failure and predict failure before occurrence has become critical for our society and our way of life. This study was performed to add to existing research in the understanding of the relationships between the corrosion current of the embedded carbon steel rebars in reinforced concrete, rebar mass loss due to corrosion and the degradation of the mechanical properties of the carbon steel embedded in high performance concrete structures. The study also aimed to study the influence of different independent variables such as the chloride solution reservoir size and the concrete composition of the prepared specimens for the study. Specimens for the study were prepared by embedding three carbon steel size #4 rebars in blocks of high performing concrete with different admixture to enhance their performance against corrosion. To initiate corrosion specimens were exposed to accelerated chloride transport method (electromigration). To accelerate corrosion some samples were selected for anodic polarization and additional electromigration. After corrosion initiation, the rebars Open Circuit Potential (OCP) and corrosion current (Icorr) were periodically measured using a galvanostat device from April 2017 to August 2021. The OCP average values showed that all the rebars considered in this study were in active corrosion. Faraday’s law was used to determine the rebar calculated mass loss from the measured corrosion current and the elapse time between measurements. The rebar mass loss was in turn used to model the loss of the physical properties of the rebar (yield strength, ultimate strength, and ultimate strain) using (Vanama & Ramakrishnan, 2020) model. Analysis of these parameters results showed a direct relationship between the measured corrosion current and the calculated mass loss of the corroding rebar. The study also showed a direct relationship between the calculated mass loss of the corroding rebar and the degradation of the physical properties of the rebar.
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Date Issued
2021
PURL
http://purl.flvc.org/fau/fd/FA00013843
Subject Headings
Corrosion, Reinforced concrete--Deterioration, Carbon steel, High strength concrete
Format
Document (PDF)