Pub Date : 2007-06-01DOI: 10.1080/17747120.2007.9692961
V. Nguyễn, Boumediene Nedjar, J. Torrenti
ABSTRACT We present in this work a modeling of calcium leaching in concrete by taking into account the influence of aggregates. The modeling consists of the derivation of the microscopic equation governing the average concentration field in the equivalent medium as well as the determination of the macroscopic transport parameters. The homogenization method allows estimating the diffusion and tortuosity tensor to be introduced in the macroscopic formulation of mass conservation law. These estimates depend on the morphological parameters which represent the geometry of the domain occupied by the phase in which the diffusion process takes places. Finally, numerical simulations are compared with experimental results on concrete.
{"title":"Modélisation de la lixiviation des matériaux cimentaires","authors":"V. Nguyễn, Boumediene Nedjar, J. Torrenti","doi":"10.1080/17747120.2007.9692961","DOIUrl":"https://doi.org/10.1080/17747120.2007.9692961","url":null,"abstract":"ABSTRACT We present in this work a modeling of calcium leaching in concrete by taking into account the influence of aggregates. The modeling consists of the derivation of the microscopic equation governing the average concentration field in the equivalent medium as well as the determination of the macroscopic transport parameters. The homogenization method allows estimating the diffusion and tortuosity tensor to be introduced in the macroscopic formulation of mass conservation law. These estimates depend on the morphological parameters which represent the geometry of the domain occupied by the phase in which the diffusion process takes places. Finally, numerical simulations are compared with experimental results on concrete.","PeriodicalId":368904,"journal":{"name":"Revue Européenne de Génie Civil","volume":"83 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132022407","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2007-06-01DOI: 10.1080/17747120.2007.9692955
Paul Sardini, A. Bertron, Christelle De La Asunciòn-Parreira, M. Siitari-Kauppi, Dimitri Prêt, G. Escadeillas, S. Sammartino, O. Amiri
ABSTRACT Degradation of cementitious matrix in aggressive aqueous environments among others is accompanied by modifications of the spatial distribution of connected porosity. The application of the 14C or 3H-PMMA (polyméthylmethacrylate) impregnation method gives a quantitative and multi-scale representation of this distribution. The first application concerns a mortar, allowing to visualise and to quantify the in situ cement porosity. The second application is related to a cement paste degraded by organic acids. This tool has many potential applications in the field of cementitious materials. It allows a sharp characterisation of internal porosity variations frequently found during durability studies, and furthermore, it provides a realistic geometrical representation of pore space that can be used for solute transfer modelling.
{"title":"Distribution spatiale de la porosité des matériaux cimentaires","authors":"Paul Sardini, A. Bertron, Christelle De La Asunciòn-Parreira, M. Siitari-Kauppi, Dimitri Prêt, G. Escadeillas, S. Sammartino, O. Amiri","doi":"10.1080/17747120.2007.9692955","DOIUrl":"https://doi.org/10.1080/17747120.2007.9692955","url":null,"abstract":"ABSTRACT Degradation of cementitious matrix in aggressive aqueous environments among others is accompanied by modifications of the spatial distribution of connected porosity. The application of the 14C or 3H-PMMA (polyméthylmethacrylate) impregnation method gives a quantitative and multi-scale representation of this distribution. The first application concerns a mortar, allowing to visualise and to quantify the in situ cement porosity. The second application is related to a cement paste degraded by organic acids. This tool has many potential applications in the field of cementitious materials. It allows a sharp characterisation of internal porosity variations frequently found during durability studies, and furthermore, it provides a realistic geometrical representation of pore space that can be used for solute transfer modelling.","PeriodicalId":368904,"journal":{"name":"Revue Européenne de Génie Civil","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124388282","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2007-06-01DOI: 10.1080/17747120.2007.9692951
V. Baroghel-Bouny, M. Thiéry, F. Barberon, O. Coussy, G. Villain
ABSTRACT In this paper, the liquid water permeability has been investigated by various methods in laboratory conditions. A comparison has been performed between the “intrinsic” permeabilities thus obtained. The values have also been compared to the results obtained from gas permeability measurement. The results point out that the concept of intrinsic permeability, independent of the permeating fluid, is not relevant for cementitious materials, when liquid water is regarded, except maybe for highly permeable ones. The various physicochemical processes likely to occur during the tests can explain the significant differences observed. The apparent chloride diffusion coefficient has been assessed by means of diffusion and electrical migration tests. The differences recorded have been discussed. They can be explained in particular by the various microstructural changes that occur during these two types of tests, as illustrated by MIP and 29Si NMR results.
{"title":"Assessment of transport properties of cementitious materials","authors":"V. Baroghel-Bouny, M. Thiéry, F. Barberon, O. Coussy, G. Villain","doi":"10.1080/17747120.2007.9692951","DOIUrl":"https://doi.org/10.1080/17747120.2007.9692951","url":null,"abstract":"ABSTRACT In this paper, the liquid water permeability has been investigated by various methods in laboratory conditions. A comparison has been performed between the “intrinsic” permeabilities thus obtained. The values have also been compared to the results obtained from gas permeability measurement. The results point out that the concept of intrinsic permeability, independent of the permeating fluid, is not relevant for cementitious materials, when liquid water is regarded, except maybe for highly permeable ones. The various physicochemical processes likely to occur during the tests can explain the significant differences observed. The apparent chloride diffusion coefficient has been assessed by means of diffusion and electrical migration tests. The differences recorded have been discussed. They can be explained in particular by the various microstructural changes that occur during these two types of tests, as illustrated by MIP and 29Si NMR results.","PeriodicalId":368904,"journal":{"name":"Revue Européenne de Génie Civil","volume":"34 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124592637","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2007-06-01DOI: 10.1080/17747120.2007.9692962
Ismail Yurtdas, Shouyi Xie, J. Secq, Nicolas Burlion, J. Shao, M. Sibai, Pierre Brossolet, B. Fraboulet
ABSTRACT This experimental study is interested in the chemical degradation effect on the hydraulic behaviour of a cement paste, according to the mechanical loading under temperature. The tests carried out show that the permeability decreases with increase in confining pressure, in a more important way for chemically degraded material. Under creep with weak confining, the permeability of degraded material decreases, contrary to that of sound material, because of the preponderance of the compaction effect with regard to the induced microcracking. Under simultaneous creep and chemical degradation, the permeability increases due to the dissolved chemical products.
{"title":"Couplage comportement mécanique et perméabilité","authors":"Ismail Yurtdas, Shouyi Xie, J. Secq, Nicolas Burlion, J. Shao, M. Sibai, Pierre Brossolet, B. Fraboulet","doi":"10.1080/17747120.2007.9692962","DOIUrl":"https://doi.org/10.1080/17747120.2007.9692962","url":null,"abstract":"ABSTRACT This experimental study is interested in the chemical degradation effect on the hydraulic behaviour of a cement paste, according to the mechanical loading under temperature. The tests carried out show that the permeability decreases with increase in confining pressure, in a more important way for chemically degraded material. Under creep with weak confining, the permeability of degraded material decreases, contrary to that of sound material, because of the preponderance of the compaction effect with regard to the induced microcracking. Under simultaneous creep and chemical degradation, the permeability increases due to the dissolved chemical products.","PeriodicalId":368904,"journal":{"name":"Revue Européenne de Génie Civil","volume":"31 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121664978","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2007-06-01DOI: 10.1080/17747120.2007.9692957
E. Lemarchand, L. Dormieux, Catherine A. Davy, F. Skoczylas
ABSTRACT A micromechanics-based analysis is developed throughout this paper in order to study stress loading/permeability couplings in cracked porous media. Fracture closure phenomena under macrocopic compressive stresses are addressed for a fracture modelled as an arrangement of parallel cracks. This first multiscale step emphasizes the key role of the cracks connectedness on the macroscopic permeability evolution with respect to the applied confining pressure.
{"title":"Analyse micromécanique du couplage perméabilité-contrainte d'une argilite fracturée","authors":"E. Lemarchand, L. Dormieux, Catherine A. Davy, F. Skoczylas","doi":"10.1080/17747120.2007.9692957","DOIUrl":"https://doi.org/10.1080/17747120.2007.9692957","url":null,"abstract":"ABSTRACT A micromechanics-based analysis is developed throughout this paper in order to study stress loading/permeability couplings in cracked porous media. Fracture closure phenomena under macrocopic compressive stresses are addressed for a fracture modelled as an arrangement of parallel cracks. This first multiscale step emphasizes the key role of the cracks connectedness on the macroscopic permeability evolution with respect to the applied confining pressure.","PeriodicalId":368904,"journal":{"name":"Revue Européenne de Génie Civil","volume":"204 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114754545","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2007-06-01DOI: 10.1080/17747120.2007.9692954
P. Mounanga, P. Poullain, G. Bastian, Abdelhafid Khelidj
ABSTRACT At very early age, cementitious systems can undergo thermal variations due to the double exothermic and thermoactivated property of cement hydration. The parameters of this thermochemical coupling (thermal conductivity, specific heat capacity, apparent activation energy and chemical affinity) have been identified from the literature and measured on cement pastes during the first 24 hours of hydration. They are then used in a 2D numerical model for the computing of hydration degree and temperature field of hardening cement-based materials. The aim is to quantify the effect of the thermophysical parameter values on the prediction of the material's behaviour at very early age. The sensitivity study shows that the influence of thermal property values is particularly significant in the case of temperature field computation.
{"title":"Etude du couplage thermochimique au sein de matrices cimentaires en cours d'hydratation","authors":"P. Mounanga, P. Poullain, G. Bastian, Abdelhafid Khelidj","doi":"10.1080/17747120.2007.9692954","DOIUrl":"https://doi.org/10.1080/17747120.2007.9692954","url":null,"abstract":"ABSTRACT At very early age, cementitious systems can undergo thermal variations due to the double exothermic and thermoactivated property of cement hydration. The parameters of this thermochemical coupling (thermal conductivity, specific heat capacity, apparent activation energy and chemical affinity) have been identified from the literature and measured on cement pastes during the first 24 hours of hydration. They are then used in a 2D numerical model for the computing of hydration degree and temperature field of hardening cement-based materials. The aim is to quantify the effect of the thermophysical parameter values on the prediction of the material's behaviour at very early age. The sensitivity study shows that the influence of thermal property values is particularly significant in the case of temperature field computation.","PeriodicalId":368904,"journal":{"name":"Revue Européenne de Génie Civil","volume":"33 5 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130670987","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2007-06-01DOI: 10.1080/17747120.2007.9692950
Z. Lafhaj, F. Skoczylas
{"title":"ÉDITORIAL","authors":"Z. Lafhaj, F. Skoczylas","doi":"10.1080/17747120.2007.9692950","DOIUrl":"https://doi.org/10.1080/17747120.2007.9692950","url":null,"abstract":"","PeriodicalId":368904,"journal":{"name":"Revue Européenne de Génie Civil","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124394625","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2007-06-01DOI: 10.1080/17747120.2007.9692956
A. Fabbri, O. Coussy, T. Fen-Chong
ABSTRACT A recent experimental study reveals that the less permeable a cementitious material is, the more likely surface frost damage (called scaling) happens. In order to understand how the permeability determines the mechanical response of the sample, a poromechanical approach has been built. The model allows coupling the liquid/ice crystal thermodynamic equilibrium, Darcean water transport, thermal conduction and thermoelastic properties of the different phases that form the porous material. The influence of the liquid transport on the matrix stress can then be analysed and permeability is found to be a key parameter with regard to frost durability.
{"title":"Influence of the permeability on the frost-thaw behaviour of concrete","authors":"A. Fabbri, O. Coussy, T. Fen-Chong","doi":"10.1080/17747120.2007.9692956","DOIUrl":"https://doi.org/10.1080/17747120.2007.9692956","url":null,"abstract":"ABSTRACT A recent experimental study reveals that the less permeable a cementitious material is, the more likely surface frost damage (called scaling) happens. In order to understand how the permeability determines the mechanical response of the sample, a poromechanical approach has been built. The model allows coupling the liquid/ice crystal thermodynamic equilibrium, Darcean water transport, thermal conduction and thermoelastic properties of the different phases that form the porous material. The influence of the liquid transport on the matrix stress can then be analysed and permeability is found to be a key parameter with regard to frost durability.","PeriodicalId":368904,"journal":{"name":"Revue Européenne de Génie Civil","volume":"21 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114156500","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2007-05-01DOI: 10.1080/17747120.2007.9692946
L. Jason, S. Durand
ABSTRACT The quality of a mechanical law is generally based on the evaluation of three parameters: its ability to reproduce elementary or structural characteristic behaviours (tension, compression, bending…), the efficiency of the numerical implementation (resolution algorithm or convergence) and the physical significance of its parameters. A plastic model is presented in this contribution. Based on eight coefficients which are physically representative, it is driven by two softening yield surfaces, one for tension (Rankine) and one for compression (Drucker-Prager). After a brief description of the constitutive equations, the model is tested on elementary and structural applications to validate its numerical implementation. It represents a good compromise for classical concrete behaviours, compared to other more refined, but also more complex, approaches.
{"title":"A two-surface plastic model for concrete behaviour","authors":"L. Jason, S. Durand","doi":"10.1080/17747120.2007.9692946","DOIUrl":"https://doi.org/10.1080/17747120.2007.9692946","url":null,"abstract":"ABSTRACT The quality of a mechanical law is generally based on the evaluation of three parameters: its ability to reproduce elementary or structural characteristic behaviours (tension, compression, bending…), the efficiency of the numerical implementation (resolution algorithm or convergence) and the physical significance of its parameters. A plastic model is presented in this contribution. Based on eight coefficients which are physically representative, it is driven by two softening yield surfaces, one for tension (Rankine) and one for compression (Drucker-Prager). After a brief description of the constitutive equations, the model is tested on elementary and structural applications to validate its numerical implementation. It represents a good compromise for classical concrete behaviours, compared to other more refined, but also more complex, approaches.","PeriodicalId":368904,"journal":{"name":"Revue Européenne de Génie Civil","volume":"27 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115089563","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2007-05-01DOI: 10.1080/17747120.2007.9692947
T. Ayadat, A. Hanna
ABSTRACT The drastic decrease in volume of a natural, unsaturated soil deposit or compacted fill that occurs upon wetting at virtually constant total stresses is termed “collapse”. Several methods can be found in the literature that predict collapse behavior based on easily obtained soil parameters. Nevertheless, discrepancies were reported among the results of these methods. This paper presents the results of an experimental investigation on carefully conducted laboratory prepared collapsible soils in the oedometer apparatus. These results were used to develop an empirical model for predicting soil collapse in terms of the initial dry unit weight, initial water content and the soil gradation. The values predicted by the proposed model agreed well with the experimental results of the present investigation and those available in the literature.
{"title":"Prediction of collapse behaviour in soil","authors":"T. Ayadat, A. Hanna","doi":"10.1080/17747120.2007.9692947","DOIUrl":"https://doi.org/10.1080/17747120.2007.9692947","url":null,"abstract":"ABSTRACT The drastic decrease in volume of a natural, unsaturated soil deposit or compacted fill that occurs upon wetting at virtually constant total stresses is termed “collapse”. Several methods can be found in the literature that predict collapse behavior based on easily obtained soil parameters. Nevertheless, discrepancies were reported among the results of these methods. This paper presents the results of an experimental investigation on carefully conducted laboratory prepared collapsible soils in the oedometer apparatus. These results were used to develop an empirical model for predicting soil collapse in terms of the initial dry unit weight, initial water content and the soil gradation. The values predicted by the proposed model agreed well with the experimental results of the present investigation and those available in the literature.","PeriodicalId":368904,"journal":{"name":"Revue Européenne de Génie Civil","volume":"23 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132291302","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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