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C Alonso - One of the best experts on this subject based on the ideXlab platform.
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Corrosion Rate evolution in concrete structures exposed to the atmosphere
Cement & Concrete Composites, 2002Co-Authors: C Andrade, C Alonso, J SarriaAbstract:Abstract The data on Corrosion Rate values measured on-site in real size concrete structures are scarce, while the data bank of values in laboratory specimens is relatively larger. The majority of the experiments in the laboratory have been performed in chambers of controlled relative humidity and temperature, however real outdoor climate usually is characterized by day–night and seasonal temperature cycles. These cycles, or natural weathering, influence the internal relative humidity of the concrete and the Corrosion Rate of the steel. In the present paper, results of Corrosion Rate of steel in chloride containing concretes exposed to natural weathering, are presented. Four main weather events have been identified to influence the Corrosion Rate of reinforcements due to the changes of the hydrothermal situation of the concrete: (a) day–night cycles, (b) seasonal cycles, (c) extreme temperatures and (d) rain periods. In unsheltered conditions it is the rain (moisture content of the concrete) which controls the Corrosion Rate. In concretes sheltered from rain it is the temperature the controlling factor of the moisture content and then, of the Corrosion Rate. Moisture is well represented by the electrical resistivity. A pure Arrhenius trend of the Corrosion Rate could not be found because several counter balance effects develop when temperature changes. The resistivity is the parameter that more comprehensively represents the Corrosion Rate.
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on site measurements of Corrosion Rate of reinforcements
Construction and Building Materials, 2001Co-Authors: C Andrade, C AlonsoAbstract:Abstract The increasing number of structures suffering Corrosion makes the study of their structural safety of importance. The assessment of the residual load-bearing capacity based on the quantification of the actual degree of damage and the prediction of its evolution needs measurement of the steel Corrosion Rate. Electrical potential and resistivity mapping are the most commonly known techniques, although they are merely qualitative. The measurement of the Corrosion Rate itself is now feasible. However, the technique is still not extensively used. In this paper, a brief basis of the correct measurement of the Corrosion Rate is given. The most accuRate method is based on the modulated confinement of the current which enables us to limit the steel area polarized by the current. The method is based on the determination of the polarization resistance. In the second part of the paper, the variability of the measured Corrosion current due to weather variations is commented on, and values of the time of wetness, as well as of the climatic parameters which influence the moisture content of the concrete, are given in order to obtain the representative value of the Corrosion current to be implemented into the structural calculations. The paper ends with a brief description of this implementation.
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natural weathering influence on the rebar Corrosion Rate
PROCEEDINGS OF THE INTERNATIONAL CONFERENCE ON CORROSION AND REHABILITATION OF REINFORCED CONCRETE STRUCTURES HELD 7-11 DECEMB 1998 ORLANDO FLORIDA US, 1999Co-Authors: C Andrade, C Alonso, J SarriaAbstract:There are relatively few data on Corrosion Rate values measured o reinforcing steel in concrete on-site in real size structures, wh the data bank of values in laboratory specimens is relatively lar The majority of the experiments in the laboratory have been perfo in chambers of controlled relative humidity and temperature, howe real outdoor climate usually is characterized by day-night and seasonal temperature cycles. These cycles, or natural weathering, influence the internal relative humidity of the concrete and the Corrosion Rate of the steel. In the present paper, results of Corrosion Rate of steel in chloride containing concretes exposed natural weathering are presented. Four main weather events have b identified to influence the Corrosion Rate of reinforcements due the changes of the hydrothermal situation of the concrete: a) day-night cycles, b) seasonal cycles, c) extreme temperatures and rain periods. In unsheltered conditions it is the rain (moisture content of the concrete) which controls the Corrosion Rate. In concretes sheltered from rain, the temperature is the controlling factor of the moisture content and then, of the Corrosion Rate. Moisture is well represented by the electrical resistivity. A pur Arrhenius trend of the Corrosion Rate could not be found because several counter balance effects develop when temperature changes. resistivity is the parameter that more comprehensively represents Corrosion Rate. For the covering abstract see ITRD E117314.
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Corrosion Rate monitoring in the laboratory and on site
Construction and Building Materials, 1996Co-Authors: C Andrade, C AlonsoAbstract:Abstract The loss of metal per unit of surface and time defines the metallic Corrosion Rate. A review is made of the different electrochemnical methods used for measuring this parameter. Thus, polarization curves, polarization resistance transient techniques and electrochemical impedance are commented on. Some semiquantitative methods such as the measurement of the Corrosion potential, concrete resistivity or galvanic current are also discussed. Concerning the application of electrochemical techniques for measuring Corrosion Rates on-site, the paper reviews some of the methods published in the literature with special attention to the sensorized confinement of the current. Finally, the values of Corrosion Rate measured in concrete specimens in the laboratory and on-site are given and levels of risk regarding loss in rebar cross-section are suggested.
Bernhard Elsener - One of the best experts on this subject based on the ideXlab platform.
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Corrosion Rate of carbon steel in carbonated concrete – A critical review
Cement and Concrete Research, 2018Co-Authors: Matteo Stefanoni, Ueli Angst, Bernhard ElsenerAbstract:Reinforced concrete with lower environmental footprint (lower CO2emission) can be obtained by reducing the clinker content in the cements. As the carbonation of concrete is faster, Corrosion of steel in carbonated concrete during the propagation phase is becoming important both for science and practice. The present literature review summarizes the state of the art, reporting Corrosion Rate data for a broad range of cement types, w/b ratios and environmental conditions. Correlations between Corrosion Rate and the main influencing parameters are elaboRated and discussed. It confirms that the Corrosion Rate of steel in carbonated concrete is not under ohmic control. More important are the degree of pore saturation and the effective steel area in contact with water filled pores. It also emerges that the new blended cements have to be systematically studied with respect to the Corrosion behavior of steel in carbonated concrete in order to make reliable service life prediction.
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Corrosion Rate of carbon steel in carbonated concrete a critical review
Cement and Concrete Research, 2018Co-Authors: Matteo Stefanoni, Ueli Angst, Bernhard ElsenerAbstract:Abstract Reinforced concrete with lower environmental footprint (lower CO2 emission) can be obtained by reducing the clinker content in the cements. As the carbonation of concrete is faster, Corrosion of steel in carbonated concrete during the propagation phase is becoming important both for science and practice. The present literature review summarizes the state of the art, reporting Corrosion Rate data for a broad range of cement types, w/b ratios and environmental conditions. Correlations between Corrosion Rate and the main influencing parameters are elaboRated and discussed. It confirms that the Corrosion Rate of steel in carbonated concrete is not under ohmic control. More important are the degree of pore saturation and the effective steel area in contact with water filled pores. It also emerges that the new blended cements have to be systematically studied with respect to the Corrosion behavior of steel in carbonated concrete in order to make reliable service life prediction.
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Corrosion Rate of steel in concrete: evaluation of confinement techniques for on-site Corrosion Rate measurements
Materials and Structures, 2009Co-Authors: Peter V. Nygaard, Mette R. Geiker, Bernhard ElsenerAbstract:Earlier on-site investigations and laboratory studies have shown that varying Corrosion Rates are obtained when different commercially available instruments are used. The different confinement techniques, rather than the different electrochemical techniques used in the instruments, are considered to be the main reason for the discrepancies. This paper presents a method for the quantitative assessment of confinement techniques. The assessment is based on monitoring the operation of the Corrosion Rate instrument and following the current distribution between the electrode assembly on the concrete surface and a segmented reinforcement bar embedded in the concrete. The applicability of the method was demonstRated for two commercially available Corrosion Rate instruments based on different confinement techniques. The method provided an explanation of the differences in performance of the two instruments. Correlated measurements of linear polarisation resistance and macro-cell currents allowed the determination of calibration factors. Both instruments overestimated the Corrosion Rate of passive reinforcement, but underestimated the Corrosion Rate of reinforcement with intense localised Corrosion.
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Corrosion Rate of steel in concrete measurements beyond the tafel law
Corrosion Science, 2005Co-Authors: Bernhard ElsenerAbstract:Abstract The rapid galvanostatic pulse technique was applied on site on a large number of measuring points with reinforcement varying from severely corroding to passive state. The measurements provide reliable results on Corrosion potential, ohmic resistance and polarization resistance in very short time. The overall scatter of the data is not bigger than with any other instrumentation used for Corrosion Rate determination in the field. For actively corroding zones the current from the counter electrode is self-confined, no guard-ring is needed and the Corrosion Rate can be calculated on the basis of the reinforcement area under the counter-electrode. For passive zones the calculated “Corrosion Rate” is overestimated (on a very low level). Corrosion Rate calculated from polarization resistance data are always instantaneous values. For engineering application (residual service life) the daily and seasonal changes in Corrosion Rate have to be considered. In the frequent case of chloride induced localized Corrosion the local penetration Rates calculated from R p data can vary up to a factor of 5–10 and local penetration Rates of 1 mm/year may occur. This uncertainty on a very high level of Corrosion Rate is much more important than variations induced by using devices with or without guard ring.
C Andrade - One of the best experts on this subject based on the ideXlab platform.
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Corrosion Rate evolution in concrete structures exposed to the atmosphere
Cement & Concrete Composites, 2002Co-Authors: C Andrade, C Alonso, J SarriaAbstract:Abstract The data on Corrosion Rate values measured on-site in real size concrete structures are scarce, while the data bank of values in laboratory specimens is relatively larger. The majority of the experiments in the laboratory have been performed in chambers of controlled relative humidity and temperature, however real outdoor climate usually is characterized by day–night and seasonal temperature cycles. These cycles, or natural weathering, influence the internal relative humidity of the concrete and the Corrosion Rate of the steel. In the present paper, results of Corrosion Rate of steel in chloride containing concretes exposed to natural weathering, are presented. Four main weather events have been identified to influence the Corrosion Rate of reinforcements due to the changes of the hydrothermal situation of the concrete: (a) day–night cycles, (b) seasonal cycles, (c) extreme temperatures and (d) rain periods. In unsheltered conditions it is the rain (moisture content of the concrete) which controls the Corrosion Rate. In concretes sheltered from rain it is the temperature the controlling factor of the moisture content and then, of the Corrosion Rate. Moisture is well represented by the electrical resistivity. A pure Arrhenius trend of the Corrosion Rate could not be found because several counter balance effects develop when temperature changes. The resistivity is the parameter that more comprehensively represents the Corrosion Rate.
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on site measurements of Corrosion Rate of reinforcements
Construction and Building Materials, 2001Co-Authors: C Andrade, C AlonsoAbstract:Abstract The increasing number of structures suffering Corrosion makes the study of their structural safety of importance. The assessment of the residual load-bearing capacity based on the quantification of the actual degree of damage and the prediction of its evolution needs measurement of the steel Corrosion Rate. Electrical potential and resistivity mapping are the most commonly known techniques, although they are merely qualitative. The measurement of the Corrosion Rate itself is now feasible. However, the technique is still not extensively used. In this paper, a brief basis of the correct measurement of the Corrosion Rate is given. The most accuRate method is based on the modulated confinement of the current which enables us to limit the steel area polarized by the current. The method is based on the determination of the polarization resistance. In the second part of the paper, the variability of the measured Corrosion current due to weather variations is commented on, and values of the time of wetness, as well as of the climatic parameters which influence the moisture content of the concrete, are given in order to obtain the representative value of the Corrosion current to be implemented into the structural calculations. The paper ends with a brief description of this implementation.
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natural weathering influence on the rebar Corrosion Rate
PROCEEDINGS OF THE INTERNATIONAL CONFERENCE ON CORROSION AND REHABILITATION OF REINFORCED CONCRETE STRUCTURES HELD 7-11 DECEMB 1998 ORLANDO FLORIDA US, 1999Co-Authors: C Andrade, C Alonso, J SarriaAbstract:There are relatively few data on Corrosion Rate values measured o reinforcing steel in concrete on-site in real size structures, wh the data bank of values in laboratory specimens is relatively lar The majority of the experiments in the laboratory have been perfo in chambers of controlled relative humidity and temperature, howe real outdoor climate usually is characterized by day-night and seasonal temperature cycles. These cycles, or natural weathering, influence the internal relative humidity of the concrete and the Corrosion Rate of the steel. In the present paper, results of Corrosion Rate of steel in chloride containing concretes exposed natural weathering are presented. Four main weather events have b identified to influence the Corrosion Rate of reinforcements due the changes of the hydrothermal situation of the concrete: a) day-night cycles, b) seasonal cycles, c) extreme temperatures and rain periods. In unsheltered conditions it is the rain (moisture content of the concrete) which controls the Corrosion Rate. In concretes sheltered from rain, the temperature is the controlling factor of the moisture content and then, of the Corrosion Rate. Moisture is well represented by the electrical resistivity. A pur Arrhenius trend of the Corrosion Rate could not be found because several counter balance effects develop when temperature changes. resistivity is the parameter that more comprehensively represents Corrosion Rate. For the covering abstract see ITRD E117314.
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Corrosion Rate monitoring in the laboratory and on site
Construction and Building Materials, 1996Co-Authors: C Andrade, C AlonsoAbstract:Abstract The loss of metal per unit of surface and time defines the metallic Corrosion Rate. A review is made of the different electrochemnical methods used for measuring this parameter. Thus, polarization curves, polarization resistance transient techniques and electrochemical impedance are commented on. Some semiquantitative methods such as the measurement of the Corrosion potential, concrete resistivity or galvanic current are also discussed. Concerning the application of electrochemical techniques for measuring Corrosion Rates on-site, the paper reviews some of the methods published in the literature with special attention to the sensorized confinement of the current. Finally, the values of Corrosion Rate measured in concrete specimens in the laboratory and on-site are given and levels of risk regarding loss in rebar cross-section are suggested.
J L Moramendoza - One of the best experts on this subject based on the ideXlab platform.
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fe3c influence on the Corrosion Rate of mild steel in aqueous co2 systems under turbulent flow conditions
Corrosion Science, 2002Co-Authors: J L Moramendoza, S TurgooseAbstract:The Corrosion and Corrosion inhibition of mild steel in CO2 satuRated solutions were studied under turbulent flow conditions at different pH. Electrochemical measurements using a.c. and d.c. techniques in uninhibited solutions of pH 3.8 indicated the formation of protective surface films (FeCO3) in short immersion times. However, as the exposure time was increased the Corrosion Rate always increased, an effect attributed to the increased surface area of Fe3C residue from Corrosion of the steel. At pH 5.5, the Corrosion Rate always increased with time, behaviour also associated with the presence of Fe3C surface film. The huge cathodic area of Fe3C seems to have a more important impact on the electrochemical behaviour than the poorly formed FeCO3 products. The effect of Fe3C on inhibition by a quaternary amine inhibitor at pH 3.8 is to increase the Corrosion Rate as the pre-Corrosion time is increased. The Fe3C causes either (a) a cathodic area increase reflected in the Corrosion Rate increase with time or (b) a potential gradient in the pores of the Fe3C layer that prevents positively charge amine ions from reaching all anodic sites.
Dan M Frangopol - One of the best experts on this subject based on the ideXlab platform.
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reinforced concrete bridge deck reliability model incorporating temporal and spatial variations of probabilistic Corrosion Rate sensor data
Reliability Engineering & System Safety, 2008Co-Authors: Philip S Marsh, Dan M FrangopolAbstract:The reliability of reinforced concrete (RC) bridge decks depends significantly on the Rate of Corrosion of the reinforcing steel. Structural health monitoring (SHM) techniques, including embedded Corrosion Rate sensors, can greatly improve the quantification of the steel Corrosion Rate, which can lead to improved estimates of structural safety and serviceability. Due to uncertainties in concrete properties, environmental conditions, and other factors, the Rate of Corrosion of reinforcing steel can be highly variable, both within a given structural component and over time. By placing multiple Corrosion Rate sensors throughout a structural component, such as a bridge deck, these spatial and temporal variabilities can be monitored and as such better predicted, for use in a reliability model. The objective of this investigation is to present a reliability model for a RC bridge deck incorporating both spatial and temporal variations of probabilistic Corrosion Rate sensor data. This objective is accomplished using a computational reliability model and Monte Carlo simulation. Corrosion Rate sensor data is assumed for multiple critical sections throughout a RC bridge deck over time by applying empirical spatial and temporal relationships. This data is then used to improve an existing spatially invariant reliability model. The improved reliability model incorpoRates several sub-models to determine the changes in load effects on and resistance of a RC bridge deck slab over time, as well as spatial correlation of Corrosion and a system approach to account for spatial variability. The improved reliability model incorporating both spatial and temporal variations in Corrosion Rate data provides a better estimate of the service life of a RC bridge deck slab.
