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Methodology To Evaluate The Corrosion Condition Of Bridge Decks Containing Epoxy Coated Reinforcing Steel
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Book Synopsis Methodology to Evaluate the Corrosion Condition of Bridge Decks Containing Epoxy Coated Reinforcing Steel by :
Download or read book Methodology to Evaluate the Corrosion Condition of Bridge Decks Containing Epoxy Coated Reinforcing Steel written by and published by . This book was released on 1995 with total page 14 pages. Available in PDF, EPUB and Kindle. Book excerpt: In the U.S., epoxy coated reinforcing steel has been used extensively in bridge construction for over 15 years. Major studies over the last five years or so have examined past and current practices on the use of epoxy coatings to prevent corrosion of reinforcing steel. These studies and the experiences of some state highway agencies indicate a postential for less service life than previously expected. consequently, it is projected that a methodologoy will be needed to evaluate the corrosion condition of bridge structures containing epoxy coated reinforcing steel. As in the case of bridge structures with black reinforcement, a properly conducted corrosionn condition survey provides the information required to select appropriate repair and/or rehabilitation strategies.
Book Synopsis Methods of Corrosion Protection and Durability of Concrete Bridge Decks Reinforced with Epoxy-coated Bars - Phase I by : Lisa M. Samples
Download or read book Methods of Corrosion Protection and Durability of Concrete Bridge Decks Reinforced with Epoxy-coated Bars - Phase I written by Lisa M. Samples and published by . This book was released on 1999 with total page 276 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Increasing Bridge Deck Service Life by : Robert Frosch
Download or read book Increasing Bridge Deck Service Life written by Robert Frosch and published by . This book was released on 2014-12-31 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The objective of this research program was to examine the efficacy of using alternative materials in a bridge deck from both technical and economic perspectives. For the technical evaluation (Volume 1), a three phase experimental investigation was conducted considering a wide range of corrosion-resistant reinforcing materials. These materials included stainless steels, microcomposite steel, and coated steels considering a variety of metallic and nonmetallic coatings. The first phase evaluated the bond between corrosion-resistant reinforcement and concrete using lap splice tests. The second phase evaluated the cracking behavior of slabs reinforced with corrosion-resistant reinforcement. Finally, the third phase evaluated corrosion resistance under uncracked and cracked conditions using macrocell test specimens. Transverse steel was also tied to the longitudinal steel to simulate actual bridge deck conditions. Recommendations are provided on development and splice lengths for both conventional black and corrosion-resistant reinforcing steel, control of cracks widths, as well as the selection, design, and construction of corrosion-resistant reinforcement. For the economic evaluation (Volume 2), a decision support methodology and associated spreadsheet tool for robust analysis of the cost-effectiveness of alternative material types for bridge deck reinforcement was developed. The two evaluation criteria are agency and user costs, and the input data that influence this criteria include the deck service life, material process, discount rate, detour length, and bridge size. The methodology incorporates analytical techniques that include life cycle analyses to evaluate the long-term cost and benefits of each material over the bridge life; Monte Carlo simulation to account for the probabilistic nature of the input variables; stochastic dominance to ascertain the probability distribution of the outcome that a specific reinforcement material is superior to others; and analytical hierarchical process to establish appropriate weights for the agency and user costs. Methodology is demonstrated using a case study involving three reinforcement material alternatives: traditional (epoxy-coated) steel, zinc-clad steel, and stainless steel. Through this study, it is demonstrated that the use of corrosion-resistant reinforcing materials can significantly increase bridge deck life, reduce agency and user costs associated with bridge deck rehabilitation and maintenance, and thus lower the financial needs for long-term preservation of bridges.
Book Synopsis Performance Evaluation of Iowa Bridge Decks Constructed with Epoxy-coated Reinforcing Bars by : James P. Donnelly
Download or read book Performance Evaluation of Iowa Bridge Decks Constructed with Epoxy-coated Reinforcing Bars written by James P. Donnelly and published by . This book was released on 2011 with total page 187 pages. Available in PDF, EPUB and Kindle. Book excerpt: Epoxy coatings have been used on the embedded reinforcing bars of bridge decks since the mid-1970s to mitigate deterioration caused by chloride-induced corrosion. The use of chloride-based deicers became common in the early 1960s and caused corrosion of conventional uncoated bars in bridge decks within 5 to 10 years of commencement of deicer applications. In response to this rapid deterioration, the National Bureau of Standards researched coatings to protect the reinforcement (National Bureau of Standards, 1975), resulting in the development of epoxy-coated reinforcing bars, which were used in bridge decks beginning in 1973. While corrosion-related deterioration has been prevalent on bridge decks with uncoated reinforcing bars in northern climates where the use of deicing salts is common, bridge decks constructed after 1973 with epoxy-coated reinforcing have shown good corrosion resistance with only limited exceptions. On the whole, previous laboratory and field studies regarding the performance of epoxy-coated reinforcing bars are very promising; however, some laboratory and field studies have yielded differing results. In recent years, maintenance personnel for the Iowa Department of Transportation (Iowa DOT) have reportedly performed patch repairs to some bridge decks reinforced with epoxy-coated bars. At one such bridge, the southbound US 65 bridge (Bridge No. 7788.5L065) over the Union Pacific Railroad near Bondurant in Polk County, Iowa, deck repairs were performed by Iowa DOT maintenance personnel in the Spring of 2010, based on our communications regarding this topic with Mr. Gordon Port of the Iowa DOT. These repairs were observed by engineers from the Iowa DOT Office of Bridges and Structures, who reported that significant corrosion was found at a number of epoxy-coated reinforcing bars uncovered during this patch work. These repairs were reportedly performed at spalls and delaminated areas corresponding to cracks over transverse reinforcing bars, and involved careful removal of the concrete from over the bars. Figures 1 through 4 contain photographs provided by Iowa DOT personnel showing the removal process (Figure 1), the conditions encountered (Figures 2 and 3), and close-up views of the corroded reinforcing (Figure 4). As a result of these observations, the Iowa Department of Transportation has requested this study to gain further understanding of the long-term performance of bridge decks reinforced with epoxy-coated bars. The two main objectives of this study are to determine the long-term effectiveness of the epoxy coatings and to determine the potential causes for the deterioration at locations where corrosion has occurred. Wiss, Janney, Elstner Associates, Inc. (WJE) and the Iowa DOT identified eight different bridge decks across Iowa for this study that were constructed using epoxy-coated reinforcing bars. A field investigation consisting of visual inspections, a delamination survey, a concrete cover survey, electrical testing for susceptibility to corrosion, and concrete sampling was conducted within a survey area deemed to be representative of the condition of each bridge deck. Laboratory testing, including chloride ion content testing, characterization of the extracted bars, petrographic examination of the concrete, and carbonation testing, was conducted on the core samples taken from each bridge deck.
Book Synopsis Nondestructive Evaluation of Epoxy-coated Reinforcing Bars in Concrete Using Bi-electrode Half-cell Potential Techniques by : Stephen R. Sharp
Download or read book Nondestructive Evaluation of Epoxy-coated Reinforcing Bars in Concrete Using Bi-electrode Half-cell Potential Techniques written by Stephen R. Sharp and published by . This book was released on 2006 with total page 30 pages. Available in PDF, EPUB and Kindle. Book excerpt: This study evaluated two half-cell mapping methods for nondestructive evaluation of epoxy-coated rebar (ECR) in concrete: the semi-fixed bi-electrode and the moving bi-electrode methods. These methods were expected to provide early detection of corrosion-related damage and ensure adequate time for repair. The techniques were evaluated by comparing the half-cell measurements using the two half-cell mapping techniques and measurements using the standard half-cell technique. The study found that in concrete specimens the response of both bi-electrode techniques was similar to that of the standard half-cell technique. Each technique was sensitive enough to distinguish between ponded and unponded regions along the Type I test beams. Although additional research is required to determine exactly how sensitive either bi-electrode technique is for assessing corrosion of ECR in concrete, it is clear that the use of any nondestructive tool for condition surveys of bridge decks would benefit VDOT and Virginia. The author recommends that the Type I test beams used in this study continue to be ponded until corrosion is initiated to aid in understanding the benefit of using the two bi-electrode methods during the various stages of corrosion. In addition, the Virginia Department of Transportation's Structure & Bridge Division should identify two structures that are beginning to show signs of corrosion, one bridge with ECR and the other with bare bar, to be used in a field study to determine if either bi-electrode method would benefit VDOT as a condition survey tool.
Book Synopsis Measuring the Field Corrosion Activity of Bridge Decks Built with Bare and Epoxy Coated Steel by : A. Ramniceanu
Download or read book Measuring the Field Corrosion Activity of Bridge Decks Built with Bare and Epoxy Coated Steel written by A. Ramniceanu and published by . This book was released on 2006 with total page 17 pages. Available in PDF, EPUB and Kindle. Book excerpt: Epoxy coated steel became the prevalent corrosion protection methods starting in the early 1980s. Since then, studies have shown that epoxy coating does not prevent corrosion, but instead will debond from the steel reinforcement in as little as four years, allowing instead a much more insidious form of corrosion to take place under the coating. Therefore, it is important to determine if nondestructive corrosion activity detection methods are applicable to epoxy coated reinforcing steel as well as institute guidelines for interpreting the results. Based on comparisons of measurements distributions, this study shows that there is an indication that these nondestructive test methods may be applicable to structures reinforced with epoxy coated steel.
Book Synopsis Field Performance of Epoxy-coated Reinforcing Steel in Virginia Bridge Decks by :
Download or read book Field Performance of Epoxy-coated Reinforcing Steel in Virginia Bridge Decks written by and published by . This book was released on 2000 with total page 38 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this study, the corrosion protection performance of epoxy-coated reinforcing steel (ECR) was evaluated using approximately 250 concrete cores from 18 bridge decks in Virginia. The decks were 2 to 20 years old at the time of the investigation. The deck field inspections included a crack survey and cover depth determination in the right traffic lane. A maximum of 12 cores with the top reinforcement randomly located in the lowest 12th percentile cover depth were taken from each bridge deck. Because of the safety concerns associated with taking cores from the lower steel mat, and to minimize damage to the bridge, a maximum of only 3 cores were taken through the truss bars. The laboratory evaluation of the concrete cores included a visual examination and a determination of the carbonation depth, moisture content, absorption, percent saturation, and chloride content at a 13-mm depth. The rapid chloride permeability test was also performed for the surface and base concrete on samples obtained from the cores taken through the truss bars to determine chloride permeability. The ECR inspection consisted of a visual examination, a damage evaluation, and a determination of coating thickness and adhesion. The condition of the steel underneath the epoxy coating was also evaluated. Adhesion loss of the epoxy coating to the steel surface was detected in all but one deck that was 4 years old and older. The epoxy coatings were debonding from the reinforcing bars. Whereas a bonded coating can be expected to protect the steel, a debonded coating allows chlorides, moisture, and oxygen to reach the steel and initiate a rapid corrosion mechanism. Reinforcing bars in various stages of adhesion loss showed visible signs of a corrosion process underneath the coating, suggesting that ECR will provide little or no additional service life for concrete bridge decks in comparison to bare steel. Other systems that will provide longer protection against chloride-induced corrosion of the reinforcing steel with a higher degree of reliability should be considered.
Book Synopsis Corrosion Protection Performance of Epoxy-coated Reinforcing Bars by : José Antonio Pincheira
Download or read book Corrosion Protection Performance of Epoxy-coated Reinforcing Bars written by José Antonio Pincheira and published by . This book was released on 2008 with total page 224 pages. Available in PDF, EPUB and Kindle. Book excerpt: The main purpose of this investigation was to conduct an in-depth study to determine the level of corrosion protection offered by epoxy-coated bars in four bridge decks in the Minneapolis/St. Paul, MN metropolitan area. The bridges studied were built between 1973 and 1978 and all decks had a top mat built with epoxy-coated bars. The bottom mat was epoxy-coated in only one deck whereas black steel was used for the bottom mat in the other bridges. These bridges had been assessed in 1996 and thus, the present study is a follow up investigation to obtain data and assess the field performance of epoxy-coated bars over a period of approximately 30 years. The investigation included field inspection and surveys of the decks, as well as laboratory tests of concrete core and bar samples. After 30 years of service, the overall condition of the epoxy-coated bars is good to very good, with no or modest levels of corrosion activity. In only one bridge, corrosion activity appears to be moderate to severe. The majority of corroded bars were found near joints or at crack locations. The amount of delamination in all decks is very low.
Book Synopsis Corrosion Investigation of Four Bridges Built Between 1973 and 1978 Containing Epoxy-coated Reinforcing Steel by : Paul D. Krauss
Download or read book Corrosion Investigation of Four Bridges Built Between 1973 and 1978 Containing Epoxy-coated Reinforcing Steel written by Paul D. Krauss and published by . This book was released on 1996 with total page 178 pages. Available in PDF, EPUB and Kindle. Book excerpt: Wiss, Janney, Elstner Associates, Inc., performed an in-depth field investigation into the performance of epoxy-coated reinforcing bars in four bridge decks. The study included two decks built on steel girders and two built on precast concrete girders. Two decks had been overlaid with a 2-in. low slump overlay. The bridges were all built between 1973 and 1978. Visual crack and delamination surveys were performed. Core samples were drilled for determination of chloride concentrations and to examine the embedded steel. Polarization resistance, half-cell, and AC impedance measurements were taken, but were not conclusive. Further development is needed. Laboratory testing included inspection of the coating, holiday and thickness tests, coating adhesion tests, and underfilm contamination.
Book Synopsis Corrosion Protection Service Life of Epoxy-coated Reinforcing Steel in Virginia Bridge Decks by : Michael Carey Brown
Download or read book Corrosion Protection Service Life of Epoxy-coated Reinforcing Steel in Virginia Bridge Decks written by Michael Carey Brown and published by . This book was released on 2003 with total page 63 pages. Available in PDF, EPUB and Kindle. Book excerpt: The corrosion protection service life extension provided by epoxy-coated reinforcement (ECR) was determined by comparing ECR and bare steel bars from 10 Virginia bridge decks built between 1981 and 1995. The objective was to determine the corrosion protection service life time extension provided by ECR field specimens with various degrees of coating adhesion: disbonded, partially disbonded, and wholly bonded coatings. The size and length distributions of cracks in Virginia bridge decks were investigated to assess the frequency and severity of cracks. Correlation of cracks with chloride penetration was used to characterize the influence of cracking on deck deterioration. Cracks influence the rate of chloride penetration, but the frequency and width distributions of cracks indicate that cracks are not likely to shorten the overall service life of most bridge decks in Virginia. Altogether, 141 drilled cores, 102 mm (4 inches) in diameter, were employed in this study. For each of the decks built with ECR, 10 to 12 cores were drilled through a top reinforcing bar adjacent to the previous study core locations. In addition, approximately 3 cores were drilled through a top reinforcing bar at a surface crack location. Laboratory testing involved nondestructive monitoring using advanced electrochemical techniques to periodically assess the corrosion state of the steel bars during cyclic exposure to chloride-rich solution over 36 months of treatment. Time of corrosion initiation and time of cracking (where applicable), as well as chloride content of the concrete before and after treatment, were used in the analysis. Analysis of the epoxy coating after treatment showed the presence of micro cracks in the surface of some coatings, and moisture uptake and glass transition temperatures, as related to curing of the coatings, were investigated. Less than 25 percent of all Virginia bridge decks built under specifications in place since 1981 is projected to corrode sufficiently to require rehabilitation within 100 years, regardless of bar type. The corrosion service life extension attributable to ECR in bridge decks was found to be approximately 5 years beyond that of bare steel and, therefore, ECR is not a cost-effective method of corrosion prevention for bridge decks. Deleting the requirement for ECR in decks would save Virginia approximately $845,000 per year.
Book Synopsis Service Life Extension of Virginia Bridge Decks Afforded by Epoxy-Coated Reinforcement by : MC. Brown
Download or read book Service Life Extension of Virginia Bridge Decks Afforded by Epoxy-Coated Reinforcement written by MC. Brown and published by . This book was released on 2006 with total page 13 pages. Available in PDF, EPUB and Kindle. Book excerpt: A study was conducted on concrete core samples each containing a single top-mat reinforcing steel bar from ten bridge decks in Virginia. Two of the bridges contained conventional, uncoated mild reinforcing steel (Bare), and eight of the bridges were constructed with epoxy-coated reinforcement (ECR). The bridges ranged in age from 4 to 18 years, and were built under same specifications for concrete water-to-cement ratio (w/c) and cover depth. In the laboratory, the subject cores were prepared and corrosion activity was monitored via electrochemical impedance spectroscopy while subject to cyclic ponding of a 3 % NaCl solution over a 22-month exposure period. The relative corrosion performance of the Bare and ECR bars were evaluated, by comparison of the time to corrosion initiation and time to failure, as designated by visible cracking of the concrete cover. A stochastic model was employed, using bootstrap resampling techniques, to project the corrosion protection service life extension provided by epoxy-coated reinforcement as compared to Bare steel for the population of Virginia bridge decks. Less than 25 % of all Virginia bridge decks built under specifications in place since 1981 were projected to corrode sufficiently to require rehabilitation within 100 years, regardless of bar type. The corrosion service life extension attributable to ECR in bridge decks was found to be approximately 5 years beyond that of Bare steel.
Book Synopsis Multiple Corrosion Protection Systems for Reinforced Concrete Bridge Components by :
Download or read book Multiple Corrosion Protection Systems for Reinforced Concrete Bridge Components written by and published by . This book was released on 2011 with total page 260 pages. Available in PDF, EPUB and Kindle. Book excerpt: Eleven systems containing epoxy-coated reinforcement (ECR) in combination with another corrosion-protection system are evaluated using the rapid macrocell, southern exposure, cracked beam, linear polarization resistance, and field tests. The systems include bars pretreated with zinc chromate to improve the adhesion between the epoxy and the reinforcing steel, two epoxies with improved adhesion to the reinforcing steel, one inorganic corrosion inhibitor (calcium nitrite), two organic corrosion inhibitors (Rheocrete® 222+ and HycreteTM), an epoxy-coated bar with a primer containing microencapsulated calcium nitrite, three epoxy-coated bars with improved adhesion combined with the corrosion inhibitor calcium nitrite, and multiple-coated (MC) bars with an initial 50-microm (2-mil) coating of 98 percent zinc and 2 percent aluminum followed by a conventional epoxy coating. The systems are compared with conventional uncoated reinforcement and conventional ECR. The coatings on all bars are penetrated to simulate the effects of damage during fabrication and placement in the field. The results presented in this report indicate that the coated bars provide superior corrosion protection to the reinforcing steel and that bars with damaged coatings initiate corrosion at chloride contents within concrete that are several times greater and corrode at rates that are typically two orders of magnitude below those exhibited by conventional reinforcement. Limited additional protection is achieved using bars with the primer coating, MC bars, and concrete containing the corrosion inhibitors calcium nitrite and one of the organic corrosion inhibitors, although the latter resulted in reduced compressive strength and reduced resistance to surface scaling. The differences in costs over a 75-year design life are relatively small for coated bars. Cracks in concrete directly over and parallel to the reinforcement, such as found in bridge decks, result in earlier corrosion initiation and higher corrosion rates than obtained with intact concrete for all systems. Epoxies that provide initially high adhesion to the underlying steel provide no advantage over conventional epoxy coatings. All coated bars that were evaluated exhibited corrosion losses at openings through the coating. A reduction in adhesion between an epoxy coating and the reinforcing steel occurs after a period of exposure to corrosive conditions. This reduction increases with increasing chloride content in the concrete and in the presence of cracks and decreases with the use of corrosion inhibitors, with the use of MC reinforcement, and with electrical isolation of the epoxy-coated bars from each other. Corrosion products form under the coating where adhesion has been reduced. For periods up to five years under exposure conditions representative of those in bridge decks, the reduction in adhesion between an epoxy coating and the reinforcing steel did not affect the rate at which coated bars corrode.
Book Synopsis An Evaluation of the Performance of Epoxy-coated Reinforcing Steel in Concrete Exposure Specimens by :
Download or read book An Evaluation of the Performance of Epoxy-coated Reinforcing Steel in Concrete Exposure Specimens written by and published by . This book was released on 1998 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The application of a mineral admixture or a combination of a mineral admixture with corrosion inhibitor are the methods used for the corrosion protection for reinforced concrete bridges. The results of a 1.5-year study on evaluation of three concretes with fly ash, slag cement (SC), and silica fume (SF) and one concrete with silica fume and a corrosion inhibitor (SFD) are presented. The specimens were built to simulate four exposure conditions typical for concrete bridges located in the coastal region or inland where deicing salts are used. The exposure conditions were horizontal, vertical, tidal, and immersed zones. The specimens were kept inside the laboratory and were exposed to weekly ponding cycles of 6% sodium chloride solution by weight. In addition, cover depth measurements from 21 bridge decks and chloride data from 3 bridge decks were used, together with laboratory data, in modeling the service lives of investigated corrosion protection methods. The methods used to assess the condition of the specimens included chloride concentration measurements, corrosion potentials, and corrosion rates (3LP). Additionally, visual observations were performed for identification of rust stains and cracking on concrete surfaces. The results of chloride testing indicate that the amount of chlorides present at the bar level is more than sufficient to initiate corrosion. Chloride and rapid permeability data demonstrate that for low permeable (LP) concretes there appears to be significant difference both in a rate of chloride ingress and in the diffusion coefficients in comparison to the controls. Corrosion potentials agree with corrosion rates and suggest the possibility of an active corrosion process development on control specimens during indoor exposure. The structural cracks that were observed in some specimens appeared to have no influence on the corrosion development on the bars in the vicinity of the these cracks. It was concluded that the silicone and duct tape protection was adequate. The cracking, other than structural, appeared to be related to the reinforcing steel corrosion, except the cracks in the horizontal zone of the specimen with slag cement which were probably caused by the subsidence cracking. The least number of cracks was observed on the SF and SFD specimens. Modeling the time as a function of probability of the end of functional service life (EFSL) was presented. It has been shown that the distributions of surface concentrations of chloride ions (C0) and diffusion constants (Dc) are key elements in the model. Model predictions show that the LP concretes provide much better level of protection against moisture and chlorides than the A4 concrete alone. Application of a corrosion inhibitor causes an elevation of the chloride threshold resulting in an additional increase in time to EFSL. Recommendations are to continue monitoring until cracking has occurred in all specimens to a greater extent to better estimate the service lives of LP concretes than is presently known in the construction of concrete bridge components in Virginia. The specimens with LP concretes and one control (continuous reinforcement in the legs) should be taken to the Hampton Road North 1 Tunnel Island and placed in the brackish water to a depth of the immersed zone at low tide for further exposure to chloride. The other control (non-continuous reinforcement in the legs) should remain in an outdoor exposure in Southwest Virginia like the Civil Engineering Materials Research Laboratory in Blacksburg, Virginia. Also more field studies are needed to better estimate distributions of surface chloride concentration and diffusion coefficient of Virginia bridge decks, and to confirm predicted times to EFSL for LP concretes.
Book Synopsis תכנית לפיתוח מיומנויות תקשורת לא מילולית by :
Download or read book תכנית לפיתוח מיומנויות תקשורת לא מילולית written by and published by . This book was released on 1987 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Evaluation of Multiple Corrosion Protection Systems for Reinforced Concrete Bridge Decks by : Matthew O'Reilly
Download or read book Evaluation of Multiple Corrosion Protection Systems for Reinforced Concrete Bridge Decks written by Matthew O'Reilly and published by . This book was released on 2011 with total page 522 pages. Available in PDF, EPUB and Kindle. Book excerpt: "The performance of corrosion protection systems for reinforcing steel in concrete is evaluated. In addition to conventional and conventional epoxy-coated reinforcement, the corrosion protection systems tested include epoxy coatings with improved adhesion to the underlying steel, conventional and conventional epoxy-coated reinforcement used in conjunction with concrete containing one of three corrosion inhibitors, DCI-S, Rheocrete 222+, or Hycrete, epoxy-coated reinforcement with a microencapsulated calcium nitrite primer, multiple-coated reinforcement with a layer of zinc between the epoxy and steel, and pickled 2205 duplex stainless steel. The systems are evaluated using bench-scale and field tests. Two bridges in Kansas, cast with 2205 stainless steel, are monitored using corrosion potential mapping. Epoxy-coated and multiplecoated bars are evaluated to determine the effect of corrosion loss and time on the disbondment of the epoxy coating. Conventional, galvanized, and epoxy-coated reinforcement are evaluated using impressed current to determine the corrosion loss required to crack concrete for each system. A finite element model is developed to represent general and localized corrosion, and the results are used to develop a relationship between concrete cover, bar diameter, and area of bar corroding, and the corrosion loss required to crack concrete. An analysis of pore solutions expressed from cement pastes containing corrosion inhibitors is performed, with pH and selected ion concentrations measured from solutions collected one and seven days after casting. The results obtained from bench-scale and field test specimens are used to estimate cost effectiveness for each system under a 75-year service life. The results show epoxy coatings significantly reduce the corrosion rate compared to conventional reinforcement. Corrosion inhibitors significantly reduce corrosion rates in uncracked concrete. In cracked concrete, corrosion inhibitors also reduce corrosion rates, but their relative effectiveness is reduced. Specimens containing Hycrete exhibit the lowest corrosion rates; however, field specimens containing Hycrete also show signs of scaling. Epoxies with improved adhesion exhibit no improvement over conventional epoxy-coated reinforcement in terms of corrosion rate or disbondment of the epoxy coating. Multiple-coated reinforcement exhibits significantly less disbondment than epoxy-coated reinforcement. Pickled 2205 reinforcement exhibits the least corrosion among all systems tested. Testing of conventional and galvanized reinforcement indicates galvanized reinforcement requires more than twice as much corrosion loss to crack the surrounding concrete compared to conventional reinforcement."--Technical report documentation page.
Book Synopsis Performance of Epoxy-coated Reinforcing Steel in Highway Bridges by : Kenneth C. Clear
Download or read book Performance of Epoxy-coated Reinforcing Steel in Highway Bridges written by Kenneth C. Clear and published by Transportation Research Board. This book was released on 1995 with total page 164 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Impact of Deck Cracking on Durability by : Fouad Fanous
Download or read book Impact of Deck Cracking on Durability written by Fouad Fanous and published by . This book was released on 2000 with total page 132 pages. Available in PDF, EPUB and Kindle. Book excerpt: Concrete bridge decks subjected to corrosive environment because of the application of de-icing chemical could deteriorate at a rapid rate. In an effort to minimize corrosion of the reinforcement and the corresponding delaminations and spalls, the Iowa Department of Transportation started using epoxy-coated rebars (ECR) in the top mat of reinforcing around 1976 and in both mats 10 years later. The overall objective of this research was to determine the impact of deck cracking on durability and estimate the remaining functional service life of a bridge deck. This was accomplished by conducting a literature review, visually inspecting several bridge decks, collecting and sampling test cores from cracked and uncracked areas of bridge decks, determining the extent to which epoxy-coated rebars deteriorate at the site of cracks, and evaluating the impact of cracking on service life.
