Dépouillements

Aspects of long-term durability of reinforced concrete structures in marine environments / Melchers, Robert E. in European journal of environmental and civil engineering, Vol. 15 N° 7 (Août 2011) 

Public ISBD [article]  in European journal of environmental and civil engineering > Vol. 15 N° 7 (Août 2011) . - pp. 969-980 Titre : Aspects of long-term durability of reinforced concrete structures in marine environments Type de document : texte imprimé Auteurs : Melchers, Robert E., Auteur ; Torill Pape, Auteur Année de publication : 2011 Article en page(s) : pp. 969-980 Note générale : Génie Civil Langues : Anglais (eng) Mots-clés : Corrosion  Seawater  Reinforcement  Concrete  Structures Index. décimale : 624 Constructions du génie civil et du bâtiment. Infrastructures. Ouvrages en terres. Fondations. Tunnels. Ponts et charpentes Résumé : Much concern exists about the apparently short durability of reinforced concrete structures in marine environments. However, there are many examples of structures that have survived for long periods of time with little evidence of reinforcement corrosion. Some of these were made with seawater as mixing water. Others had very little concrete cover. Detailed examination has revealed that reinforced concrete structures made with fine or coarse aggregate consisting of calcium carbonates such as limestone or seashells or with non-reactive dolomite have extended times to commencement of corrosion initiation and to active corrosion. The reasons for this are explored herein. In addition it is shown that some structures can have serious localized reinforcement corrosion without obvious exterior signs such as concrete cracking and delamination. This requires urgent research. DEWEY : 624 ISSN : 1964-8189 En ligne : http://ejece.revuesonline.com/article.jsp?articleId=16500 [article] Aspects of long-term durability of reinforced concrete structures in marine environments [texte imprimé] / Melchers, Robert E., Auteur ; Torill Pape, Auteur . - 2011 . - pp. 969-980. Génie Civil Langues : Anglais (eng) in European journal of environmental and civil engineering > Vol. 15 N° 7 (Août 2011) . - pp. 969-980 Mots-clés : Corrosion  Seawater  Reinforcement  Concrete  Structures Index. décimale : 624 Constructions du génie civil et du bâtiment. Infrastructures. Ouvrages en terres. Fondations. Tunnels. Ponts et charpentes Résumé : Much concern exists about the apparently short durability of reinforced concrete structures in marine environments. However, there are many examples of structures that have survived for long periods of time with little evidence of reinforcement corrosion. Some of these were made with seawater as mixing water. Others had very little concrete cover. Detailed examination has revealed that reinforced concrete structures made with fine or coarse aggregate consisting of calcium carbonates such as limestone or seashells or with non-reactive dolomite have extended times to commencement of corrosion initiation and to active corrosion. The reasons for this are explored herein. In addition it is shown that some structures can have serious localized reinforcement corrosion without obvious exterior signs such as concrete cracking and delamination. This requires urgent research. DEWEY : 624 ISSN : 1964-8189 En ligne : http://ejece.revuesonline.com/article.jsp?articleId=16500

On uncertainties and inaccuracies in empirical chloride ingress modelling / Lars-Olof Nilsson in European journal of environmental and civil engineering, Vol. 15 N° 7 (Août 2011) 

Public ISBD [article]  in European journal of environmental and civil engineering > Vol. 15 N° 7 (Août 2011) . - pp. 981-990 Titre : On uncertainties and inaccuracies in empirical chloride ingress modelling Type de document : texte imprimé Auteurs : Lars-Olof Nilsson, Auteur ; Jens M. Frederiksen, Auteur Année de publication : 2011 Article en page(s) : pp. 981-990 Note générale : Génie Civil Langues : Anglais (eng) Mots-clés : Concrete  Chloride  Models  Uncertainties  Errors  Misuse Index. décimale : 624 Constructions du génie civil et du bâtiment. Infrastructures. Ouvrages en terres. Fondations. Tunnels. Ponts et charpentes Résumé : This paper gives an overview of the current state-of-the-art of modelling chloride ingress and focuses on identified uncertainties and inaccuracies in the common way of applying the widely used empirical models. Examples are given in order to quantify the inaccuracies. It is also pointed out that inherent model uncertainties are likely to be of great importance due to lack of homogeneity in the data set laying behind the models. A major part of the parameter uncertainties is due to misunderstandings and lack of knowledge of decisive parts of the models, such as the time-dependency of the chloride diffusivity and the timedependency of the surface chloride content. DEWEY : 624 ISSN : 1964-8189 En ligne : http://ejece.revuesonline.com/article.jsp?articleId=16501 [article] On uncertainties and inaccuracies in empirical chloride ingress modelling [texte imprimé] / Lars-Olof Nilsson, Auteur ; Jens M. Frederiksen, Auteur . - 2011 . - pp. 981-990. Génie Civil Langues : Anglais (eng) in European journal of environmental and civil engineering > Vol. 15 N° 7 (Août 2011) . - pp. 981-990 Mots-clés : Concrete  Chloride  Models  Uncertainties  Errors  Misuse Index. décimale : 624 Constructions du génie civil et du bâtiment. Infrastructures. Ouvrages en terres. Fondations. Tunnels. Ponts et charpentes Résumé : This paper gives an overview of the current state-of-the-art of modelling chloride ingress and focuses on identified uncertainties and inaccuracies in the common way of applying the widely used empirical models. Examples are given in order to quantify the inaccuracies. It is also pointed out that inherent model uncertainties are likely to be of great importance due to lack of homogeneity in the data set laying behind the models. A major part of the parameter uncertainties is due to misunderstandings and lack of knowledge of decisive parts of the models, such as the time-dependency of the chloride diffusivity and the timedependency of the surface chloride content. DEWEY : 624 ISSN : 1964-8189 En ligne : http://ejece.revuesonline.com/article.jsp?articleId=16501

Application of the periodic homogenization technique to ionic transfer in cementitious materials / Khaled Bourbatache in European journal of environmental and civil engineering, Vol. 15 N° 7 (Août 2011) 

Public ISBD [article]  in European journal of environmental and civil engineering > Vol. 15 N° 7 (Août 2011) . - pp. 991-1001 Titre : Application of the periodic homogenization technique to ionic transfer in cementitious materials : Case of chloride in concrete Type de document : texte imprimé Auteurs : Khaled Bourbatache, Auteur ; Olivier Millet, Auteur ; Abdelkarim Aït Mokhtar, Auteur Année de publication : 2011 Article en page(s) : pp. 991-1001 Note générale : Génie Civil Langues : Anglais (eng) Mots-clés : Ionic  transfer  Periodic  homogenization  Chlorides  ions  Cementitious  materials Index. décimale : 624 Constructions du génie civil et du bâtiment. Infrastructures. Ouvrages en terres. Fondations. Tunnels. Ponts et charpentes Résumé : In this paper we propose two macroscopic models of ionic transfer in saturated porous media. These models are established by using periodic homogenization technique for two regimes of transfer (weakly or strongly accelerated). For each regime of transfer, the associated macroscopic model obtained (pure migration or coupled diffusion-migration model) depends on the order of magnitude of the dimensionless numbers characterizing the transfer naturally introduced. Oppositely, the associated homogenised diffusion tensor is identical in the two cases of transfer considered; it depends only on the geometrical complexity of the microstructure of the porous medium. Finally numerical simulations are carried out on periodic porous media in order to calculate the corresponding homogenized diffusion tensor and to compare it with experimental results for the case of chlorides in cementitious materials. DEWEY : 624 ISSN : 1964-8189 En ligne : http://ejece.revuesonline.com/article.jsp?articleId=16502 [article] Application of the periodic homogenization technique to ionic transfer in cementitious materials : Case of chloride in concrete [texte imprimé] / Khaled Bourbatache, Auteur ; Olivier Millet, Auteur ; Abdelkarim Aït Mokhtar, Auteur . - 2011 . - pp. 991-1001. Génie Civil Langues : Anglais (eng) in European journal of environmental and civil engineering > Vol. 15 N° 7 (Août 2011) . - pp. 991-1001 Mots-clés : Ionic  transfer  Periodic  homogenization  Chlorides  ions  Cementitious  materials Index. décimale : 624 Constructions du génie civil et du bâtiment. Infrastructures. Ouvrages en terres. Fondations. Tunnels. Ponts et charpentes Résumé : In this paper we propose two macroscopic models of ionic transfer in saturated porous media. These models are established by using periodic homogenization technique for two regimes of transfer (weakly or strongly accelerated). For each regime of transfer, the associated macroscopic model obtained (pure migration or coupled diffusion-migration model) depends on the order of magnitude of the dimensionless numbers characterizing the transfer naturally introduced. Oppositely, the associated homogenised diffusion tensor is identical in the two cases of transfer considered; it depends only on the geometrical complexity of the microstructure of the porous medium. Finally numerical simulations are carried out on periodic porous media in order to calculate the corresponding homogenized diffusion tensor and to compare it with experimental results for the case of chlorides in cementitious materials. DEWEY : 624 ISSN : 1964-8189 En ligne : http://ejece.revuesonline.com/article.jsp?articleId=16502

Effect of solution concentration on the attack of concrete by combined sulphate and chloride solutions / Manu Santhanam in European journal of environmental and civil engineering, Vol. 15 N° 7 (Août 2011) 

Public ISBD [article]  in European journal of environmental and civil engineering > Vol. 15 N° 7 (Août 2011) . - pp. 1003-1015 Titre : Effect of solution concentration on the attack of concrete by combined sulphate and chloride solutions Type de document : texte imprimé Auteurs : Manu Santhanam, Auteur Année de publication : 2011 Article en page(s) : pp. 1003-1015 Note générale : Génie Civil Langues : Anglais (eng) Mots-clés : Sulphate  attack  Seawater  attack  Solution  concentration  Compressive  strength  Thermal  analysis  Microstructure Index. décimale : 624 Constructions du génie civil et du bâtiment. Infrastructures. Ouvrages en terres. Fondations. Tunnels. Ponts et charpentes Résumé : Seawater attack presents a number of challenges to the concrete designer. The combined attack by sulphates and chlorides in seawater involves a complicated mechanism. In a number of cases, such as in outfall tunnels of seawater desalination projects, there is a possibility of encountering magnesium sulphate solutions (or magnesium brine solutions) having higher concentrations than seawater. This paper reports an experimental investigation to understand the influence of the solution concentration of seawater on the performance of cement mortars, through a combination of physical, chemical and microstructural analyses. Results indicate that higher concentrations of seawater do not cause the same level of damage as higher concentrations of groundwater relative to the typical seawater/groundwater solutions. The role of the brucite layer, formed on the surface during magnesium sulphate attack, is explored in detail to help understand the mechanisms governing the attack. DEWEY : 624 ISSN : 1964-8189 En ligne : http://ejece.revuesonline.com/article.jsp?articleId=16503 [article] Effect of solution concentration on the attack of concrete by combined sulphate and chloride solutions [texte imprimé] / Manu Santhanam, Auteur . - 2011 . - pp. 1003-1015. Génie Civil Langues : Anglais (eng) in European journal of environmental and civil engineering > Vol. 15 N° 7 (Août 2011) . - pp. 1003-1015 Mots-clés : Sulphate  attack  Seawater  attack  Solution  concentration  Compressive  strength  Thermal  analysis  Microstructure Index. décimale : 624 Constructions du génie civil et du bâtiment. Infrastructures. Ouvrages en terres. Fondations. Tunnels. Ponts et charpentes Résumé : Seawater attack presents a number of challenges to the concrete designer. The combined attack by sulphates and chlorides in seawater involves a complicated mechanism. In a number of cases, such as in outfall tunnels of seawater desalination projects, there is a possibility of encountering magnesium sulphate solutions (or magnesium brine solutions) having higher concentrations than seawater. This paper reports an experimental investigation to understand the influence of the solution concentration of seawater on the performance of cement mortars, through a combination of physical, chemical and microstructural analyses. Results indicate that higher concentrations of seawater do not cause the same level of damage as higher concentrations of groundwater relative to the typical seawater/groundwater solutions. The role of the brucite layer, formed on the surface during magnesium sulphate attack, is explored in detail to help understand the mechanisms governing the attack. DEWEY : 624 ISSN : 1964-8189 En ligne : http://ejece.revuesonline.com/article.jsp?articleId=16503

Determination of time-zero and its effect on autogenous deformation evolution / Aveline Darquennes in European journal of environmental and civil engineering, Vol. 15 N° 7 (Août 2011) 

Public ISBD [article]  in European journal of environmental and civil engineering > Vol. 15 N° 7 (Août 2011) . - pp. 1017-1029 Titre : Determination of time-zero and its effect on autogenous deformation evolution Type de document : texte imprimé Auteurs : Aveline Darquennes, Auteur ; Stéphanie Staquet, Auteur ; Bernard Espion, Auteur Année de publication : 2011 Article en page(s) : pp. 1017-1029 Note générale : Génie Civil Langues : Anglais (eng) Mots-clés : Kelly-Bryant  method  Setting  Shrinkage  Slag  cement  Resistivity  Ultrasonic  wave Index. décimale : 624 Constructions du génie civil et du bâtiment. Infrastructures. Ouvrages en terres. Fondations. Tunnels. Ponts et charpentes Résumé : The aim of this study is the determination of time-zero, a reference time from which the autogenous deformation is expressed, and the effect of this choice on the evolution of autogeneous deformation of concretes with different slag proportions (0 and 71%). The determination of time-zero is based on the setting evolution measured by means of several experimental methods (mechanical, electrical and ultrasonic). Autogenous deformation is also measured with a new shrinkage testing set-up developed at the Université Libre de Bruxelles. Following the experimental results it appears that a time-zero equal to the final setting is the most adequate choice for classic concretes. For slag cement concretes, characterized by an expansion of their cement matrix at early age, time-zero should be taken equal to the time of the expansion peak. DEWEY : 624 ISSN : 1964-8189 En ligne : http://ejece.revuesonline.com/article.jsp?articleId=16504 [article] Determination of time-zero and its effect on autogenous deformation evolution [texte imprimé] / Aveline Darquennes, Auteur ; Stéphanie Staquet, Auteur ; Bernard Espion, Auteur . - 2011 . - pp. 1017-1029. Génie Civil Langues : Anglais (eng) in European journal of environmental and civil engineering > Vol. 15 N° 7 (Août 2011) . - pp. 1017-1029 Mots-clés : Kelly-Bryant  method  Setting  Shrinkage  Slag  cement  Resistivity  Ultrasonic  wave Index. décimale : 624 Constructions du génie civil et du bâtiment. Infrastructures. Ouvrages en terres. Fondations. Tunnels. Ponts et charpentes Résumé : The aim of this study is the determination of time-zero, a reference time from which the autogenous deformation is expressed, and the effect of this choice on the evolution of autogeneous deformation of concretes with different slag proportions (0 and 71%). The determination of time-zero is based on the setting evolution measured by means of several experimental methods (mechanical, electrical and ultrasonic). Autogenous deformation is also measured with a new shrinkage testing set-up developed at the Université Libre de Bruxelles. Following the experimental results it appears that a time-zero equal to the final setting is the most adequate choice for classic concretes. For slag cement concretes, characterized by an expansion of their cement matrix at early age, time-zero should be taken equal to the time of the expansion peak. DEWEY : 624 ISSN : 1964-8189 En ligne : http://ejece.revuesonline.com/article.jsp?articleId=16504

How to assess the long-term behaviour of a mortar submitted to leaching? / Siham Kamali-Bernard in European journal of environmental and civil engineering, Vol. 15 N° 7 (Août 2011) 

Public ISBD [article]  in European journal of environmental and civil engineering > Vol. 15 N° 7 (Août 2011) . - pp. 1031-1043 Titre : How to assess the long-term behaviour of a mortar submitted to leaching? Type de document : texte imprimé Auteurs : Siham Kamali-Bernard, Auteur ; Fabrice Bernard, Auteur Année de publication : 2011 Article en page(s) : pp. 1031-1043 Note générale : Génie Civil Langues : Anglais (eng) Mots-clés : Leaching  Cement  Mortar  Diffusion  Tensile  Compression  Numerical  modelling Index. décimale : 624 Constructions du génie civil et du bâtiment. Infrastructures. Ouvrages en terres. Fondations. Tunnels. Ponts et charpentes Résumé : The long term behaviour of a mortar submitted to leaching is simulated and both its mechanical and diffusion properties successfully predicted using the 3D numerical tool, MuMoCC platform. The effect of the dissolution of the hydrates such as Portlandite (CH) and Hydrated (sulfo-) aluminates is quantified, showing their significant influence on the decrease of the elastic modulus and the compressive strength, and on the increase of ductility and diffusivity. Moreover, the evolution of both compressive stress-strain curve and effective diffusion coefficient according to leaching duration or leaching depth are predicted for a whole leached sample. DEWEY : 624 ISSN : 1964-8189 En ligne : http://ejece.revuesonline.com/article.jsp?articleId=16505 [article] How to assess the long-term behaviour of a mortar submitted to leaching? [texte imprimé] / Siham Kamali-Bernard, Auteur ; Fabrice Bernard, Auteur . - 2011 . - pp. 1031-1043. Génie Civil Langues : Anglais (eng) in European journal of environmental and civil engineering > Vol. 15 N° 7 (Août 2011) . - pp. 1031-1043 Mots-clés : Leaching  Cement  Mortar  Diffusion  Tensile  Compression  Numerical  modelling Index. décimale : 624 Constructions du génie civil et du bâtiment. Infrastructures. Ouvrages en terres. Fondations. Tunnels. Ponts et charpentes Résumé : The long term behaviour of a mortar submitted to leaching is simulated and both its mechanical and diffusion properties successfully predicted using the 3D numerical tool, MuMoCC platform. The effect of the dissolution of the hydrates such as Portlandite (CH) and Hydrated (sulfo-) aluminates is quantified, showing their significant influence on the decrease of the elastic modulus and the compressive strength, and on the increase of ductility and diffusivity. Moreover, the evolution of both compressive stress-strain curve and effective diffusion coefficient according to leaching duration or leaching depth are predicted for a whole leached sample. DEWEY : 624 ISSN : 1964-8189 En ligne : http://ejece.revuesonline.com/article.jsp?articleId=16505

Random temperature and humidity models in Atlantic environment / Denys Breysse in European journal of environmental and civil engineering, Vol. 15 N° 7 (Août 2011) 

Public ISBD [article]  in European journal of environmental and civil engineering > Vol. 15 N° 7 (Août 2011) . - pp. 1045-1058 Titre : Random temperature and humidity models in Atlantic environment Type de document : texte imprimé Auteurs : Denys Breysse, Auteur ; Myriam Chaplain, Auteur ; Antoine Marache, Auteur Année de publication : 2011 Article en page(s) : pp. 1045-1058 Note générale : Génie Civil Langues : Anglais (eng) Mots-clés : Humidity  Random  variations  Temperature  Time  correlation  Variographical  analysis  Weather  modeling Index. décimale : 624 Constructions du génie civil et du bâtiment. Infrastructures. Ouvrages en terres. Fondations. Tunnels. Ponts et charpentes Résumé : Moisture and temperature variations have a high influence on building materials behavior, like creep and durability in timber or activity of corrosion in reinforced concrete. Improving the prediction of these behaviors requires a better modeling of these variations. Variations of temperature and humidity recorded during several years at an hourly time step have been analyzed so as to make the part between a deterministic signal (explained by astronomical reasons) and a stochastic part. The variographical analysis for temperature has revealed a correlation structure of about seven days. The humidity is considered as a random variable whose variations are constrained by temperature values and physical laws (air saturation). The combined simulation enables to build synthetic climates, which present the same patterns, in terms of statistical distribution and time dynamics than real data records. These synthetic signals will be used for studying the building materials response under longterm environmental loading. An application to timber durability will be presented in a companion paper. DEWEY : 624 ISSN : 1964-8189 En ligne : http://ejece.revuesonline.com/article.jsp?articleId=16506 [article] Random temperature and humidity models in Atlantic environment [texte imprimé] / Denys Breysse, Auteur ; Myriam Chaplain, Auteur ; Antoine Marache, Auteur . - 2011 . - pp. 1045-1058. Génie Civil Langues : Anglais (eng) in European journal of environmental and civil engineering > Vol. 15 N° 7 (Août 2011) . - pp. 1045-1058 Mots-clés : Humidity  Random  variations  Temperature  Time  correlation  Variographical  analysis  Weather  modeling Index. décimale : 624 Constructions du génie civil et du bâtiment. Infrastructures. Ouvrages en terres. Fondations. Tunnels. Ponts et charpentes Résumé : Moisture and temperature variations have a high influence on building materials behavior, like creep and durability in timber or activity of corrosion in reinforced concrete. Improving the prediction of these behaviors requires a better modeling of these variations. Variations of temperature and humidity recorded during several years at an hourly time step have been analyzed so as to make the part between a deterministic signal (explained by astronomical reasons) and a stochastic part. The variographical analysis for temperature has revealed a correlation structure of about seven days. The humidity is considered as a random variable whose variations are constrained by temperature values and physical laws (air saturation). The combined simulation enables to build synthetic climates, which present the same patterns, in terms of statistical distribution and time dynamics than real data records. These synthetic signals will be used for studying the building materials response under longterm environmental loading. An application to timber durability will be presented in a companion paper. DEWEY : 624 ISSN : 1964-8189 En ligne : http://ejece.revuesonline.com/article.jsp?articleId=16506

Modelling time to failure of notched beams under random humidity variations of Atlantic environment / Myriam Chaplain in European journal of environmental and civil engineering, Vol. 15 N° 7 (Août 2011) 

Public ISBD [article]  in European journal of environmental and civil engineering > Vol. 15 N° 7 (Août 2011) . - pp. 1059-1072 Titre : Modelling time to failure of notched beams under random humidity variations of Atlantic environment Type de document : texte imprimé Auteurs : Myriam Chaplain, Auteur ; Denys Breysse, Auteur ; Antoine Marache, Auteur Année de publication : 2011 Article en page(s) : pp. 1059-1072 Note générale : Génie Civil Langues : Anglais (eng) Mots-clés : Wood  Relative  humidity  modelling  Crack  initiation  and  propagation  Lifetime  modelling Index. décimale : 624 Constructions du génie civil et du bâtiment. Infrastructures. Ouvrages en terres. Fondations. Tunnels. Ponts et charpentes Résumé : The mechanical response and durability of timber structures is highly influenced by the atmospheric conditions. Wood mechanical properties depend on moisture content, on temperature and on their variations. To study the lifetime of timber components in their environment, climatic variations are simulated and a lifetime model is proposed. The model predicts the incubation time and the time of crack propagation until the failure. As temperature has a smaller influence on the time to failure than relative humidity, its effects are not directly taken into account in the model. Predictions of the proposed model for various air humidity simulations are compared to creep test results obtained on notched beams under various climatic conditions. DEWEY : 624 ISSN : 1964-8189 En ligne : http://ejece.revuesonline.com/article.jsp?articleId=16507 [article] Modelling time to failure of notched beams under random humidity variations of Atlantic environment [texte imprimé] / Myriam Chaplain, Auteur ; Denys Breysse, Auteur ; Antoine Marache, Auteur . - 2011 . - pp. 1059-1072. Génie Civil Langues : Anglais (eng) in European journal of environmental and civil engineering > Vol. 15 N° 7 (Août 2011) . - pp. 1059-1072 Mots-clés : Wood  Relative  humidity  modelling  Crack  initiation  and  propagation  Lifetime  modelling Index. décimale : 624 Constructions du génie civil et du bâtiment. Infrastructures. Ouvrages en terres. Fondations. Tunnels. Ponts et charpentes Résumé : The mechanical response and durability of timber structures is highly influenced by the atmospheric conditions. Wood mechanical properties depend on moisture content, on temperature and on their variations. To study the lifetime of timber components in their environment, climatic variations are simulated and a lifetime model is proposed. The model predicts the incubation time and the time of crack propagation until the failure. As temperature has a smaller influence on the time to failure than relative humidity, its effects are not directly taken into account in the model. Predictions of the proposed model for various air humidity simulations are compared to creep test results obtained on notched beams under various climatic conditions. DEWEY : 624 ISSN : 1964-8189 En ligne : http://ejece.revuesonline.com/article.jsp?articleId=16507

Non destructive evaluation of concrete contamination by chloride / Jean-Paul Balayssac in European journal of environmental and civil engineering, Vol. 15 N° 7 (Août 2011) 

Public ISBD [article]  in European journal of environmental and civil engineering > Vol. 15 N° 7 (Août 2011) . - pp. 1073-1084 Titre : Non destructive evaluation of concrete contamination by chloride : Comparison of methods Type de document : texte imprimé Auteurs : Jean-Paul Balayssac, Auteur ; Stéphane Laurens, Auteur ; Gilles Klysz, Auteur Année de publication : 2011 Article en page(s) : pp. 1073-1084 Note générale : Génie Civil Langues : Anglais (eng) Mots-clés : Chloride  Moisture  NDT  Radar  Resistivity  Capacitive  technique Index. décimale : 624 Constructions du génie civil et du bâtiment. Infrastructures. Ouvrages en terres. Fondations. Tunnels. Ponts et charpentes Résumé : This paper aims to analyse the sensitivity of some NDT methods (radar, resistivity and capacitive technique) to chloride contamination. In laboratory, four different concretes with different water to cement ratio and two kinds of aggregates were conditioned with different saturation degrees of two solutions (30 g/l or 120 g/l of NaCl). NDT measurements show that the attenuation of radar waves is sensitive to the presence of chlorides but depending on the saturation degree of the solution while velocity is not affected. Resistivity is also very sensitive. The real permittivity measured at low frequency with capacitive technique is modified by the presence of chlorides. All the techniques were carried out on a real site. From the analysis of laboratory results, an attempt of evaluation of both moisture content and level of chloride contamination is proposed and compared to values obtained from cores extracted on a very near area. DEWEY : 624 ISSN : 1964-8189 En ligne : http://ejece.revuesonline.com/article.jsp?articleId=16508 [article] Non destructive evaluation of concrete contamination by chloride : Comparison of methods [texte imprimé] / Jean-Paul Balayssac, Auteur ; Stéphane Laurens, Auteur ; Gilles Klysz, Auteur . - 2011 . - pp. 1073-1084. Génie Civil Langues : Anglais (eng) in European journal of environmental and civil engineering > Vol. 15 N° 7 (Août 2011) . - pp. 1073-1084 Mots-clés : Chloride  Moisture  NDT  Radar  Resistivity  Capacitive  technique Index. décimale : 624 Constructions du génie civil et du bâtiment. Infrastructures. Ouvrages en terres. Fondations. Tunnels. Ponts et charpentes Résumé : This paper aims to analyse the sensitivity of some NDT methods (radar, resistivity and capacitive technique) to chloride contamination. In laboratory, four different concretes with different water to cement ratio and two kinds of aggregates were conditioned with different saturation degrees of two solutions (30 g/l or 120 g/l of NaCl). NDT measurements show that the attenuation of radar waves is sensitive to the presence of chlorides but depending on the saturation degree of the solution while velocity is not affected. Resistivity is also very sensitive. The real permittivity measured at low frequency with capacitive technique is modified by the presence of chlorides. All the techniques were carried out on a real site. From the analysis of laboratory results, an attempt of evaluation of both moisture content and level of chloride contamination is proposed and compared to values obtained from cores extracted on a very near area. DEWEY : 624 ISSN : 1964-8189 En ligne : http://ejece.revuesonline.com/article.jsp?articleId=16508

High dynamic range image processing for non-destructive-testing / Bidisha Ghosh in European journal of environmental and civil engineering, Vol. 15 N° 7 (Août 2011) 

Public ISBD [article]  in European journal of environmental and civil engineering > Vol. 15 N° 7 (Août 2011) . - pp. 1085-1096 Titre : High dynamic range image processing for non-destructive-testing Type de document : texte imprimé Auteurs : Bidisha Ghosh, Auteur ; Vikram Pakrashi, Auteur ; Franck Schoefs, Auteur Année de publication : 2011 Article en page(s) : pp. 1085-1096 Note générale : Génie Civil Langues : Anglais (eng) Mots-clés : High  dynamic  range  (HDR)  imaging  Non-destructive-testing  (NDT)  Pitting  corrosion  Damage  detection  Image  processing Index. décimale : 624 Constructions du génie civil et du bâtiment. Infrastructures. Ouvrages en terres. Fondations. Tunnels. Ponts et charpentes Résumé : This paper proposes High Dynamic Range (HDR) imaging as a protocol for nondestructive- testing for the first time. HDR imaging protocol has been experimentally validated on images of pitting corrosion in this paper and has been further applied to isolate a range of image backgrounds that arise out of a number of environmental conditions. The superiority of HDR imaging over a standard imaging process has been demonstrated. The results indicate that the proposed protocol is not limited by the examples considered in this paper and can readily be applied to a number of infrastructure maintenance management related applications. The protocol complements and improves standard visual inspection techniques and expert opinions. This approach immediately lends itself to further mathematical and statistical analyses, both qualitative and quantitative. DEWEY : 624 ISSN : 1964-8189 En ligne : http://ejece.revuesonline.com/article.jsp?articleId=16509 [article] High dynamic range image processing for non-destructive-testing [texte imprimé] / Bidisha Ghosh, Auteur ; Vikram Pakrashi, Auteur ; Franck Schoefs, Auteur . - 2011 . - pp. 1085-1096. Génie Civil Langues : Anglais (eng) in European journal of environmental and civil engineering > Vol. 15 N° 7 (Août 2011) . - pp. 1085-1096 Mots-clés : High  dynamic  range  (HDR)  imaging  Non-destructive-testing  (NDT)  Pitting  corrosion  Damage  detection  Image  processing Index. décimale : 624 Constructions du génie civil et du bâtiment. Infrastructures. Ouvrages en terres. Fondations. Tunnels. Ponts et charpentes Résumé : This paper proposes High Dynamic Range (HDR) imaging as a protocol for nondestructive- testing for the first time. HDR imaging protocol has been experimentally validated on images of pitting corrosion in this paper and has been further applied to isolate a range of image backgrounds that arise out of a number of environmental conditions. The superiority of HDR imaging over a standard imaging process has been demonstrated. The results indicate that the proposed protocol is not limited by the examples considered in this paper and can readily be applied to a number of infrastructure maintenance management related applications. The protocol complements and improves standard visual inspection techniques and expert opinions. This approach immediately lends itself to further mathematical and statistical analyses, both qualitative and quantitative. DEWEY : 624 ISSN : 1964-8189 En ligne : http://ejece.revuesonline.com/article.jsp?articleId=16509

Impedance based method for non-contact determination of the corrosion rate in buried metallic structures / Michel Keddam in European journal of environmental and civil engineering, Vol. 15 N° 7 (Août 2011) 

Public ISBD [article]  in European journal of environmental and civil engineering > Vol. 15 N° 7 (Août 2011) . - pp. 1097-1103 Titre : Impedance based method for non-contact determination of the corrosion rate in buried metallic structures Type de document : texte imprimé Auteurs : Michel Keddam, Auteur ; Ramon X. Novoa, Auteur ; Beatriz Puga, Auteur Année de publication : 2011 Article en page(s) : pp. 1097-1103 Note générale : Génie Civil Langues : Anglais (eng) Mots-clés : Corrosion  monitoring  Contact-less  method  Electrochemical  impedance  spectroscopy Index. décimale : 624 Constructions du génie civil et du bâtiment. Infrastructures. Ouvrages en terres. Fondations. Tunnels. Ponts et charpentes Résumé : The electrochemical impedance spectroscopy has been employed in the present investigation to assess the polarisation resistance of carbon steel rebars in different electrolytes. The measurements have been performed using the classical 3-electrode arrangement, where the element under test is the working electrode of the potentiostat, and a new 4-electrode arrangement where the element under test is floating from the electrical point of view (e.g. contact-less technique). The polarisation resistance values obtained using the contact-less technique are very close to those obtained using the traditional 3-electrode arrangement. The measurements, performed in a wide range of electrolyte resistivity values (including mortar) have thus demonstrated the applicability of this new technique for on-site corrosion rate assessment. DEWEY : 624 ISSN : 1964-8189 En ligne : http://ejece.revuesonline.com/article.jsp?articleId=16510 [article] Impedance based method for non-contact determination of the corrosion rate in buried metallic structures [texte imprimé] / Michel Keddam, Auteur ; Ramon X. Novoa, Auteur ; Beatriz Puga, Auteur . - 2011 . - pp. 1097-1103. Génie Civil Langues : Anglais (eng) in European journal of environmental and civil engineering > Vol. 15 N° 7 (Août 2011) . - pp. 1097-1103 Mots-clés : Corrosion  monitoring  Contact-less  method  Electrochemical  impedance  spectroscopy Index. décimale : 624 Constructions du génie civil et du bâtiment. Infrastructures. Ouvrages en terres. Fondations. Tunnels. Ponts et charpentes Résumé : The electrochemical impedance spectroscopy has been employed in the present investigation to assess the polarisation resistance of carbon steel rebars in different electrolytes. The measurements have been performed using the classical 3-electrode arrangement, where the element under test is the working electrode of the potentiostat, and a new 4-electrode arrangement where the element under test is floating from the electrical point of view (e.g. contact-less technique). The polarisation resistance values obtained using the contact-less technique are very close to those obtained using the traditional 3-electrode arrangement. The measurements, performed in a wide range of electrolyte resistivity values (including mortar) have thus demonstrated the applicability of this new technique for on-site corrosion rate assessment. DEWEY : 624 ISSN : 1964-8189 En ligne : http://ejece.revuesonline.com/article.jsp?articleId=16510

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