The Experts below are selected from a list of 47274 Experts worldwide ranked by ideXlab platform
Kenji Nakashita - One of the best experts on this subject based on the ideXlab platform.
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evaluation of the agno3 solution spray method for measurement of Chloride penetration into hardened cementitious matrix materials
Construction and Building Materials, 1993Co-Authors: Nobuaki Otsuki, Shigeyoshi Nagataki, Kenji NakashitaAbstract:Recently, the number of reinforced concrete structures damaged by Chloride attack has been increasing. Therefore, it is important to establish a simple method for measuring Chloride Content in concrete. Observation of the discoloured area after spraying certain indicator solutions on a fractured surface of the specimen has been considered as one of these methods. For example, UNI (Italian Standard) has recommended such a method for Chloride Contents using AgNO3 solution. The authors have examined the Chloride Content at colour change boundary and measured the electrochemical properties of steel bars in the discoloured area to clarify the engineering significance of this method.
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evaluation of agno 3 solution spray method for measurement of Chloride penetration into hardened cementitious matrix materials
Aci Materials Journal, 1992Co-Authors: Nobuaki Otsuki, Shigeyoshi Nagataki, Kenji NakashitaAbstract:Recently the number of reinforced concrete structures damaged by Chloride attack has increased. It is important to establish a simple method for measuring Chloride Content in concrete. Observation of discolored area after spraying certain indicator solutions on a fractured surface of the specimen has been considerd as one of these methods. For example UNI (Italian Standard) has recommended such a method for Chloride Contents using AgNO3 solution. The authors have examined the Chloride Content at the color change boundary and measured the electrochemical properties of steel bars in the discolored area to clarify the engineering significance of this method.
Haibo Qiu - One of the best experts on this subject based on the ideXlab platform.
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effects of Chloride Content of intravenous crystalloid solutions in critically ill adult patients a meta analysis with trial sequential analysis of randomized trials
Annals of Intensive Care, 2019Co-Authors: Ming Xue, Xiwen Zhang, Feng Liu, Wei Chang, Jianfeng Xie, Yi Yang, Haibo QiuAbstract:Background Intravenous crystalloid solutions are administered commonly for critically ill patients. We performed this meta-analysis of randomized trials with trial sequential analysis (TSA) to evaluate effects of Chloride Content of intravenous crystalloid solutions on clinical outcomes among critically ill adult patients.
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MOESM1 of Effects of Chloride Content of intravenous crystalloid solutions in critically ill adult patients: a meta-analysis with trial sequential analysis of randomized trials
2019Co-Authors: Ming Xue, Xiwen Zhang, Feng Liu, Wei Chang, Jianfeng Xie, Yi Yang, Haibo QiuAbstract:Additional file 1: Table S1. Sensitivity analysis of the effects of Chloride Content in crystalloid fluid on critically ill patientsâ outcomes. Figure S1. a Risk of bias graph. Review authorsâ judgements about each risk of bias item resented as percentages across all included studies. b Risk of bias summary for each included study Red (-) indicates high risk of bias; yellow (?) indicates unclear risk; and green (+) indicates low risk of bias. Figure S2. GRADE profile for assessing quality of evidence. Figure S3. Forest plots for indications of new RRT use after enrollment. Figure S4. Forest plots for MAKE30 in predefined subgroups. a Sepsis and non-sepsis subgroups. b Subgroups according to categories of baseline renal function. MAKE30 is for major adverse kidney events within 30 days. Figure S5. Forest plots for alterationsâ of serum Content among critically ill patients. Figure S6. Forest plots for organ support. a MV use of critically ill patients. b Ventilator-free day of critically ill patients. c Vasopressor-free days of critically ill patients. MV is for mechanic ventilation. Figure S7. Funnel plots. a Funnel plots for in-hospital mortality. b Funnel plots for 30-day mortality. c Funnel plots for 60-day mortality. d Funnel plots for development of stage 2 of higher AKI of critically ill patients. e Funnel plots for new RRT use of critically ill patients. f Funnel plots of for RRT-free days of critically ill patients. AKI is for acute kidney injury according to KDIGO criterion; RRT is for renal replacement therapy
Oystein Vennesland - One of the best experts on this subject based on the ideXlab platform.
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probabilistic considerations on the effect of specimen size on the critical Chloride Content in reinforced concrete
Corrosion Science, 2011Co-Authors: Ueli Angst, Anders Ronnquist, Bernhard Elsener, Claus K Larsen, Oystein VenneslandAbstract:Abstract A probabilistic model was used to predict the critical Chloride Content (Ccrit) for reinforcement corrosion as a function of specimen size. The specimen size is likely to be a reason for the large scatter of Ccrit values as well as for the high threshold levels often observed in laboratory setups. Regarding test methods, it is discussed that the common combination of small specimens and low numbers of parallel samples results in poor reproducibility. If experimental data is to be used for service life modelling, the geometrical dimensions of the specimens on which Ccrit was measured have to be taken into account.
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critical Chloride Content in reinforced concrete a review
Cement and Concrete Research, 2009Co-Authors: Ueli Angst, Bernhard Elsener, Claus K Larsen, Oystein VenneslandAbstract:Chloride induced corrosion as the major cause for degradation of reinforced concrete has been the subject of great research efforts over the last fifty years. The present literature review summarises the state of the art by presenting the concept of the critical Chloride Content, discussing influencing factors, and assessing available measurement techniques. A large number of published Chloride threshold values together with the respective experimental details are collected. While today's experience is mostly based on Portland cement, more modern studies with non-traditional binders often reported contradictory results. The present literature evaluation highlights the strong need for a practice-related test method, and, in this regard, focuses especially on experimental procedures by discussing advantages and drawbacks of methods and setups. It clearly emerges that many of the setups used to determine critical Chloride Contents are not suited to give realistic results.
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detecting critical Chloride Content in concrete using embedded ion selective electrodes effect of liquid junction and membrane potentials
Materials and Corrosion-werkstoffe Und Korrosion, 2009Co-Authors: Ueli Angst, Oystein VenneslandAbstract:When studying critical Chloride Content in reinforced concrete, the amount of Chloride dissolved in the pore solution is an important parameter. Ion selective electrodes offer the possibility of measuring the Chloride ion concentration (activity) in the concrete pore solution non-destructively. However, the potentiometric measurement might be disturbed by, amongst others, diffusion potentials (liquid junction potentials and membrane potentials). Laboratory samples designed to find critical Chloride Contents often involve Chloride ingress by capillary suction, diffusion or migration, and thus Chloride and pH profiles are usually present. As a result of these concentration gradients, membrane potentials are established, which markedly affect the determination of the Chloride concentration. In addition, liquid junction potentials at the interface of the concrete sample and the reference electrode contribute to the measured potential. Experimental observations in the present work illustrate the effect of liquid junction potentials on the application of ion selective electrodes in concrete. Moreover, the influence of internal membrane potentials has been estimated by a theoretical model.
Bernhard Elsener - One of the best experts on this subject based on the ideXlab platform.
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probabilistic considerations on the effect of specimen size on the critical Chloride Content in reinforced concrete
Corrosion Science, 2011Co-Authors: Ueli Angst, Anders Ronnquist, Bernhard Elsener, Claus K Larsen, Oystein VenneslandAbstract:Abstract A probabilistic model was used to predict the critical Chloride Content (Ccrit) for reinforcement corrosion as a function of specimen size. The specimen size is likely to be a reason for the large scatter of Ccrit values as well as for the high threshold levels often observed in laboratory setups. Regarding test methods, it is discussed that the common combination of small specimens and low numbers of parallel samples results in poor reproducibility. If experimental data is to be used for service life modelling, the geometrical dimensions of the specimens on which Ccrit was measured have to be taken into account.
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critical Chloride Content in reinforced concrete a review
Cement and Concrete Research, 2009Co-Authors: Ueli Angst, Bernhard Elsener, Claus K Larsen, Oystein VenneslandAbstract:Chloride induced corrosion as the major cause for degradation of reinforced concrete has been the subject of great research efforts over the last fifty years. The present literature review summarises the state of the art by presenting the concept of the critical Chloride Content, discussing influencing factors, and assessing available measurement techniques. A large number of published Chloride threshold values together with the respective experimental details are collected. While today's experience is mostly based on Portland cement, more modern studies with non-traditional binders often reported contradictory results. The present literature evaluation highlights the strong need for a practice-related test method, and, in this regard, focuses especially on experimental procedures by discussing advantages and drawbacks of methods and setups. It clearly emerges that many of the setups used to determine critical Chloride Contents are not suited to give realistic results.
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non destructive determination of the free Chloride Content in cement based materials
Materials and Corrosion-werkstoffe Und Korrosion, 2003Co-Authors: Bernhard Elsener, L Zimmermann, H BohniAbstract:A non-destructive Chloride sensitive sensor element for use in cement based porous materials is presented. The sensor element determines the activity of the free Chloride ions in solutions and in porous cement based materials such as cement paste, mortar or concrete. The calibration in synthetic pore solution showed a response according to Nernst law over three decades of Chloride concentration. The sensor element has shown excellent reproducibility and long term stability. The sensor element has been used to monitor the Chloride uptake into mortar specimens. The results show a good agreement between the free Chloride Content determined by the sensor and by pore water expression. Applications in monitoring of reinforced concrete structures and their limitations are discussed. Zerstorungsfreie Erfassung der Konzentration der freien Chloridionen in Zementstein und Mortel In der vorliegenden Arbeit wird ein Chloridsensor zur zerstorungsfreien Erfassung des Chloridgehalts in zementosen Materialien beschrieben. Der Sensor bestimmt die Aktivitat der freien Chloridionen in Losungen und in Zementstein, Mortel oder Beton. Die Kalibrierungskurve in synthetischer Betonporenlosung zeigt das erwartete Nernst'sche Verhalten uber mehr als drei Konzentrationsdekaden. Der Sensor weist eine sehr hohe Reproduzierbarkeit und Langzeitstabilitat auf. Der Chloridsensor wurde eingesetzt, um das Eindringen der Chloridionen in Mortelprufkorpern zu untersuchen. Ein Vergleich der Chloridkonzentration bestimmt durch Auspressen der Porenlosung am Ende der Versuche mit den von Sensoren bestimmten Chloridkonzentration zeigt eine sehr gute Ubereinstimmung. Praktische Anwendungen und die Einsatzgrenzen des Sensors werden diskutiert.
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the electrochemical removal of Chlorides from reinforced concrete
Corrosion Science, 1993Co-Authors: Bernhard Elsener, M Molina, H BohniAbstract:Abstract Results of a 2-year field study performed in Switzerland to evaluate the process and to obtain information on the efficiency of electrochemical Chloride removal as a restoration technique for Chloride contaminated concrete are presented. It is shown that about 50% of the initial Chloride Content is removed within 8 weeks (ca 5 × 106 C m−2). In the treated zones of the structure the half-cell potentials became more positive by about 80–100 mV. A comparison with the theoretical efficiency for Chloride removal, calculated from the transference number of Chloride ions, show that mainly the free Chlorides in the pore solution of the concrete are removed. Due to the slow chemical equilibrium between bound and free Chlorides, a second treatment after several months also removes originally bound Chlorides. For severe and inhomogeneous Chloride contamination local zones with active rebars and high Chloride Content may remain after the treatment.
Gustavo Duffo - One of the best experts on this subject based on the ideXlab platform.
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corrosion of reinforcing steel in simulated concrete pore solutions effect of carbonation and Chloride Content
Corrosion Science, 2004Co-Authors: M Moreno, W Morris, M G Alvarez, Gustavo DuffoAbstract:The corrosion susceptibility of as-received reinforcing steel bars (rebars) in solutions simulating the pore liquid of alkaline and carbonated concrete has been studied by means of potentiodynamic polarisation tests and polarisation resistance measurements. The effect of different degrees of carbonation and the presence of several Chloride Contents in the simulated pore solutions was investigated. Results show the beneficial effect of high alkalinity on the localised corrosion of steel caused by Chloride ions. From the results of the potentiodynamic tests a critical Chloride concentration above which pitting could take place was evaluated for each solution. The Chloride threshold values here found are of the same order than those previously reported in the literature for film-free steel. The results obtained in solutions simulating carbonated concrete showed that under weak carbonation conditions carbon steel does not passivate while in the presence of high levels of carbonate and bicarbonate the resistance to localised corrosion is improved.