Ureasilicate hybrid coatings for corrosion protection of galvanized steel in chloride-contaminated simulated concrete pore solution

Organic-inorganic hybrid (OIH) sol-gel coatings based on ureasilicates (U(X)) have promising properties for use as eco-friendly coatings on hot dip galvanized steel (HDGS) and may be considered potential substitutes for pre-treatment systems containing Cr(VI). These OIH coatings reduce corrosion activity during the initial stages of contact of the HDGS samples with highly alkaline environments (cementitious media) and allow the mitigation of harmful effects of an initial excessive reaction between cement pastes and the zinc layer. However, the behavior of HDGS coated with U(X) in the presence of chloride ions has never been reported. In this paper, the performance of HDGS coated with five different U(X) coatings was assessed by electrochemical measurements in chloride-contaminated simulated concrete pore solution (SCPS). U(X) sol-gel coatings were produced and deposited on HDGS by a dip coating method. The coatings performance was evaluated by electrochemical impedance spectroscopy, potentiodynamic polarization curves measurements, macrocell current density and polarization resistance in contact with chloride-contaminated SCPS. The SEM/EDS analyses of the coatings before and after the tests were also performed. The results showed that the HDGS samples coated with the OIH coatings exhibited enhanced corrosion resistance to chloride ions when compared to uncoated galvanized steel.

Erratum: Ureasilicate hybrid coatings for corrosion protection of galvanized steel in cementitious media

Artigo completo publicado na revista "Journal of The Electrochemical Society" 160:10 (2013) 467-479 e disponível no RepositóriUM em: http://hdl.handle.net/1822/33855

Erratum: Alcohol-aminosilicate hybrid coatings for corrosion protection of galvanized steel in mortar

Artigo completo publicado na revista "Journal of The Electrochemical Society" 161:6 (2014) C349-C362 e disponível no RepositóriUM em: http://hdl.handle.net/1822/33784

Erratum: Erratum: Alcohol-aminosilicate hybrid coatings for corrosion protection of galvanized steel in mortar

Artigo completo publicado na revista "Journal of The Electrochemical Society" 161:6 (2014) C349-C362 e disponível no RepositóriUM em: http://hdl.handle.net/1822/33784. Errata disponível no RepositóriUM em: http://hdl.handle.net/1822/40064. (Publisher’s note: An erratum that addressed the errors in Figure 9 was originally published on Dec. 10, 2014, however the graphs in that erratum were not correct.)

Female alcoholics: electrocardiographic changes and associated metabolic and electrolytic disorders

OBJECTIVE: To identify the electrocardiographic changes and their associations with metabolic and electrolytic changes in female alcoholics. METHODS: The study comprised 44 female alcoholics with no apparent physical disorder. They underwent the following examinations: conventional electrocardiography; serologic tests for syphilis, Chagas' disease, and hepatitis B and C viruses; urinary pregnancy testing; hematimetric analysis; biochemical measurements of albumin, fibrinogen, fasting and postprandial glycemias, lipids, hepatic enzymes, and markers for tissue necrosis and inflammation. RESULTS: Some type of electrocardiographic change was identified in 33 (75%) patients. In 17 (38.6%) patients, more than one of the following changes were present: prolonged QTc interval in 24 (54.5%), change in ventricular repolarization in 11(25%), left ventricular hypertrophy in 6 (13.6%), sinus bradycardia in 4 (9.1%), sinus tachycardia in 3 (6.8%), and conduction disorder in 3 (6.8%). The patients had elevated mean serum levels of creatine phosphokinase, aspartate aminotransferases, and gamma glutamyl transferase, as well as hypocalcemia and low levels of total cholesterol and LDL-cholesterol. The patients with altered electrocardiograms had a more elevated age, a lower alcohol consumption, hypopotassemia, and significantly elevated levels of triglycerides, postprandial glucose, sodium and gamma glutamyl transferase than those with normal electrocardiograms. The opposite occurred with fasting glycemia, magnesium, and alanine aminotransferase. CONCLUSION: The electrocardiographic changes found were prolonged QTc interval, change in ventricular repolarization, and left ventricular hypertrophy. Patients with normal and abnormal electrocardiograms had different metabolic and electrolytic changes.

The Corrosion of Career? - Occupational Trajectories of Business Economists and Engineers in Switzerland

Achievement careers are regarded as a distinctive element of the post-war period in occidental societies. Such a career was at once a modal trajectory of the modern parts of middleclass men and a social emblem for progress and success. However, if the achievement career came to be a biographical pattern with great normative power, its precise sequential course remained vague. Theories of the 1960s and 1970s described it as an orderly advancement within large firms. By the 1990s, scholars postulated an erosion of the organizational structures that once contributed to the institutionalization of careers, accompanied by a weakening of the normative weight of the achievement career by management discourse. We question the thesis of the corrosion of achievement career by analysing the trajectories of 442 engineers and business economists in Switzerland in regard to their orderliness, loyalty, and temporal rhythm. An inspection of types of careers and cohorts reveals that even if we face a decline of loyalty over time, hierarchical orderliness is not touched by those changes. Foremost, technical-industrial careers fit the loyal and regular pattern. Hence, this trajectory-type represents only a minority and is by far the slowest and least successful in terms of hierarchical ascension.

Assaigs Stress Corrosion Cracking (SCC)

En aquest projecte es presenta la realització d’un sistema d’assaig de la corrosió sota tensió (stress corrosion cracking, SCC) i un estudi de l’efecte de l’SCC sobre dos acers d’eina per matrius d’estampació en calent. L’SCC és la formació i propagació d’esquerdes en un material degut a la interacció de tres factors: un medi corrosiu, un material susceptible i una tensió estàtica aplicada. Aquestes esquerdes són difícils de detectar i poden provocar fallades catastròfiques inesperades i, en concret, s’ha detectat aquest fenomen en matrius refrigerades d’estampació en calent. Es pretén dissenyar i construir un dispositiu d’assaig SCC per tal d’utilitzar-lo per l’estudi dels materials 1.2367 i 1.2343 en condicions d’aigua de xarxa, aigua destil·lada i inhibidor. Aquests assaigs es realitzen a les temperatures de 40 i 80ºC ja que un estudi previ ha simulat les condicions de temperatura als canals de refrigeració de les matrius d’estampació en calent i s’ha vist que aquestes són les temperatures assolides. La raó d’estudiar aquests materials és perquè són dos acers d’eina per treball en calent convencionals, usats en l’àmbit de les matrius refrigerades d’estampació en calent i en general en processos de conformat en calent (forja, moldeig). S’estudia el comportament a tracció d’aquests materials en aquestes condicions comparant-lo amb el mateix assaig però en condicions en aire, i s’avaluen les diferències en la tensió màxima, la ductilitat, el mecanisme de fractura o l’esquerdament sofert. Es fa un estudi fractogràfic de les mostres mitjançant microscòpia electrònica de rastreig (SEM) i un estudi de les superfícies laterals i del secondary cracking mitjançant microscòpia òptica. Es comparen els diferents resultats obtinguts i es determina en quines condicions s’ha desenvolupat SCC i en quines no, en quina intensitat i quines opcions hi ha per evitar-lo.

Regulatory assessment of in vitro skin corrosion and irritation data within the European framework: Workshop recommendations

Validated in vitro methods for skin corrosion and irritation were adopted by the OECD and by the European Union during the last decade. In the EU, Switzerland and countries adopting the EU legislation, these assays may allow the full replacement of animal testing for identifying and classifying compounds as skin corrosives, skin irritants, and non irritants. In order to develop harmonised recommendations on the use of in vitro data for regulatory assessment purposes within the European framework, a workshop was organized by the Swiss Federal Office of Public Health together with ECVAM and the BfR. It comprised stakeholders from various European countries involved in the process from in vitro testing to the regulatory assessment of in vitro data. Discussions addressed the following questions: (1) the information requirements considered useful for regulatory assessment; (2) the applicability of in vitro skin corrosion data to assign the corrosive subcategories as implemented by the EU Classification, Labelling and Packaging Regulation; (3) the applicability of testing strategies for determining skin corrosion and irritation hazards; and (4) the applicability of the adopted in vitro assays to test mixtures, preparations and dilutions. Overall, a number of agreements and recommendations were achieved in order to clarify and facilitate the assessment and use of in vitro data from regulatory accepted methods, and ultimately help regulators and scientists facing with the new in vitro approaches to evaluate skin irritation and corrosion hazards and risks without animal data.

The corrosion of career? Occupational trajectories of engineers and business economists in Switzerland

This doctoral thesis deals with the rise and potential fall of achievement career as an institutional biographical pattern. I start with the assumption that the achievement career, as a result of the spread of large-scale bureaucratic companies, the male-breadwinner family model, and meritocratic ideals, came to life in the first half of the twentieth century. During the so-called 30 glorieuses, it became even a normatively dominant and also politically significant male biographical pattern. But the structural changes that announced the end of the post-war golden age seemed also to threaten and-according to certain scholars-erode this type of occupational trajectory. In order to understand this dynamic I will try to reconstruct the achievement career in Switzerland empirically. I examine (1) the structural changes of the economic field from 1970 to 2000, (2) the transformations of the trajectories during this period, and (3) ways in which the concerned individuals interpret and react to these changes.

Feasibility Study for Detection and Quantification of Corrosion in Bridge Barrier Rails, RB11-012, 2013

"Technical challenges exist with infrastructure that can be addressed by nondestructive evaluation (NDE) methods, such as detecting corrosion damage to reinforcing steel that anchor concrete bridge railings to bridge road decks. Moisture and chloride ions reach the anchors along the cold joint between the rails and deck, causing corrosion that weakens the anchors and ultimately the barriers. The Center for Nondestructive Evaluation at Iowa State University has experience in development of measurement techniques and new sensors using a variety of interrogating energies. This research evaluated feasibility of three technologies — x-ray radiation, ground-penetrating radar (GPR), and magnetic flux leakage (MFL) — for detection and quantification of corrosion of embedded reinforcing steel. Controlled samples containing pristine reinforcing steel with and without epoxy and reinforcing steel with 25 percent and 50 percent section reduction were embedded in concrete at 2.5 in. deep for laboratory evaluation. Two of the techniques, GPR and MFL, were used in a limited field test on the Iowa Highway 210 Bridge over Interstate 35 in Story County. The methods provide useful and complementary information. GPR provides a rapid approach to identify reinforcing steel that has anomalous responses. MFL provides similar detection responses but could be optimized to provide more quantitative correlation to actual condition. Full implementation could use either GPR or MFL methods to identify areas of concern, followed by radiography to give a visual image of the actual condition, providing the final guidance for maintenance actions." The full 103 page report and the 2 page Tech Transfer Summary are included in this link.

Deicing Salt Corrosion with and without Inhibitors, MLR-87-8, 1989

Chloride ion penetration through concrete to reinforcing steel is causing the premature deterioration of numerous bridge decks in Iowa. The purpose of the research reported in this paper was to determine whether any of several additives or alternative deicing chemicals could inhibit corrosion of reinforcing steel. The deicers tested were calcium magnesium acetate (CMA), CMA plus NaCl (NaCl: sodium chloride), Quicksalt plus PCI, and CG-90, a polyphosphate solution being developed by Cargill. Two tests were established. First, steel coupons were placed in a 15% solution of a deicer and distilled water to determine which alternative deicer would cause the least amount of corrosion in solution. The coupons were weighed periodically to determine each coupon's weight loss from corrosion. The second test involved ponding a 15% solution of each material on reinforced concrete blocks. Weekly copper-copper sulfate electrical half-cell (CSE) potential readings were taken on each block to determine whether corrosive activity was occurring at the steel surface. When the ponding research was concluded, concrete samples were taken from one of the three blocks ponded with each deicer. The samples were used to determine the chloride ion content at the level of the steel. Results show that all the deicers were less corrosive than NaCl. Only pure CMA, however, significantly inhibited the corrosion of steel embedded in concrete.

Investigation of Field Corrosion Performance and Bond/Development Length of Galvanized Reinforcing Steel, TR-666, 2014

In reinforced concrete systems, ensuring that a good bond between the concrete and the embedded reinforcing steel is critical to long-term structural performance. Without good bond between the two, the system simply cannot behave as intended. The bond strength of reinforcing bars is a complex interaction between localized deformations, chemical adhesion, and other factors. Coating of reinforcing bars, although sometimes debated, has been commonly found to be an effective way to delay the initiation of corrosion in reinforced concrete systems. For many years, the standard practice has been to coat reinforcing steel with an epoxy coating, which provides a barrier between the steel and the corrosive elements of water, air, and chloride ions. Recently, there has been an industry-led effort to use galvanizing to provide the protective barrier commonly provided by traditional epoxy coatings. However, as with any new structural product, questions exist regarding both the structural performance and corrosion resistance of the system. In the fall of 2013, Buchanan County, Iowa constructed a demonstration bridge in which the steel girders and all internal reinforcing steel were galvanized. The work completed in this project sought to understand the structural performance of galvanized reinforcing steel as compared to epoxy-coated steel and to initiate a long-term corrosion monitoring program. This work consisted of a series of controlled laboratory tests and the installation of a corrosion monitoring system that can be observed for years in the future. The results of this work indicate there is no appreciable difference between the bond strength of epoxy-coated reinforcing steel and galvanized reinforcing steel. Although some differences were observed, no notable difference in either peak load, slip, or failure mode could be identified. Additionally, a long-term monitoring system was installed in this Buchanan County bridge and, to date, no corrosion activity has been identified.

Detection of Steel Corrosion in Bridge Decks and Reinforced Concrete Pavement, HR-156, 1977

The Iowa Department of Transportation initiated this research to evaluate the reliability, benefit and application of the corrosion detection device. Through field testing prior to repair projects and inspection at the time of repair, the device was shown to be reliable. With the reliability established, twelve additional devices were purchased so that this evaluation procedure could be used routinely on all repair projects. The corrosion detection device was established as a means for determining concrete removal for repair. Removal of the concrete down to the top reinforcing steel is required for all areas exhibiting electrical potentials greater than 0.45 Volt. It was determined that the corrosion detection device was not applicable to membrane testing. The corrosion detection device has been used to evaluate corrosion of reinforcing steel in continuously reinforced concrete pavement.

Corrosion of Steel in CRCP, HR-1004, 1975

The Materials and Research Departments cooperated in planning and performing Research Project HR-1004 during the summer of 1974. The Research Department agreed to accept responsibility for the final report; it has been delayed because of our efforts to obtain a maximum amount of information from the data by means of various statistical analyses. This memorandum contains all of the data, hopefully in a manner that will permit you to proceed with your consideration of an experimental project using cathodic protection for the CRCP steel. A more detailed report will be prepared at a later date.