Papers by David Conciatori
... J. Marchand, rapporteur EFFET DU MICROCLIMAT SUR L'INITIATION DE LA CORROSION DES ACIERS... more ... J. Marchand, rapporteur EFFET DU MICROCLIMAT SUR L'INITIATION DE LA CORROSION DES ACIERS D'ARMATURE DANS LES OUVRAGES EN BÉTON ARMÉDavid CONCIATORI Page 2. Table des matières I Table des matières ...
International Journal of Reliability and Safety, 2015
Cement and Concrete Research, 2010
This article presents a comprehensive modeling of temperature, carbonation, water and chloride io... more This article presents a comprehensive modeling of temperature, carbonation, water and chloride ions transport in cover concrete using the transport model "TransChlor". The TransChlor transport model employs weather data and chloride ion concentrations present on the concrete surface to predict the temporal and spatial evolution of the presence of chloride ion concentrations in the cover concrete pores. The main features of the TransChlor model are presented and validated. The TransChlor model has been calibrated using experimental data on liquid water movement in concrete of different permeabilities under realistic microclimatic conditions. Chloride ion transport is validated by means of experimental results obtained from a newly developed chloride ion optical fiber based sensor.
International Journal of Reliability and Safety, Mar 20, 2015
Polytechnic Institute Montreal, PO Box 6079, Station Centre-ville, Main building, Room B336.8, Mo... more Polytechnic Institute Montreal, PO Box 6079, Station Centre-ville, Main building, Room B336.8, Montreal, QC H3C 3A7, Canada; EPFL MCS, Swiss Federal Institute of Technology (EPFL), Station 18 (bâtiment GC), CH-1015 Lausanne, Switzerland; Email: ...
A sensitivity analysis of the parameters involved in a multiionic reactive transport model that c... more A sensitivity analysis of the parameters involved in a multiionic reactive transport model that can be used, among other applications, to predict chloride ingress in concrete structures is presented. The analysis is based on the calculation of the elasticity of each parameter using a rigorous mathematical method. It was performed for two different test cases. The first concerns the penetration of chloride ions in saturated concrete during a simple ponding experiment while the second one involves the influence of wetting and drying cycles on chloride ingress. The analysis indicates that porosity and tortuosity (i.e. ionic diffusion coefficients) are the material parameters which have the most important impact on the model predictions. Boundary conditions were also found to have a significant influence on the output of the model. On the other hand, simulations were found to be much less affected by parameters such as the initial pore solution chemistry and the initial solid phase cont...
We are interested in explanations of the occurrence of limit states in concrete structures and wi... more We are interested in explanations of the occurrence of limit states in concrete structures and wish to specify the way in which various approaches to the determination of such states —borders between safe and failure states of concern in the service life of a concrete structure— can be said to be probabilistic. To that end, we use the Generalized Linear Model (GLM) framework and define the sense in which some recent model types can be said to be probabilistic or introduce randomness within deterministic structures.
2nd International RILEM Symposium on Advances in Concrete through Science and Engineering, 2006
ABSTRACT The steel reinforcement corrosion in reinforced concrete elements is the primary cause o... more ABSTRACT The steel reinforcement corrosion in reinforced concrete elements is the primary cause of rehabilitation interventions on concrete structures. In the domain of highway structures, the majority of corrosion is initiated by the presence of chloride ions introduced by winter de-icing salts. The deterioration evolution of highway structures therefore depends on the structure’s exposure to liquid water or water vapour containing dissolved aggressive agents like chloride ions. It has been demonstrated, the deterioration evolution rate is quicker for zones in direct contact with liquid water containing aggressive agents than in other zones not in contact with water. This paper presents laboratory tests to quantify the liquid water movement in cover concrete as a function of low temperature to determine the extent of water and chloride ion transport. The principle objective of this experimental campaign is to assess the durability of conventional structural concrete and to analyze the influence of the local microclimate conditions. Low temperature capillary tests have been conducted on various concrete test samples with different permeabilities. The concrete mixtures tested can be separated into three distinct groups based on the water to cement ratio employed, respectively 0.42, 0.52 and 0.73. The permeability of the samples was measured by air permeability and electrical resistivity tests. Prior to conducting the capillarity tests, the samples were dried to three different humidity levels, specifically, 25%, 50% and 75% relative humidity. Following the drying process, the test elements were placed in a freezer until they reached the desired temperature. Finally the capillarity tests were conducted by submerging the specimen in a low-temperature high-concentration salt solution bath at four specific temperatures, -20°C, -10°C, 0°C and +10°C.
Life-Cycle Performance of Deteriorating Structures, 2003
Chloride Penetration Model Considering Microclimate David Conciatori1, Emmanuel Denarie1, Hamid S... more Chloride Penetration Model Considering Microclimate David Conciatori1, Emmanuel Denarie1, Hamid Sadouki'and Eugen Briihwiler1 Summary Two main factors govern the ingress of chloride ions into concrete reinforced with ordinary steel reinforcement, from de-icing ...
Materials and Structures, 2014
ABSTRACT The Rosenblueth point estimator method is used to propagate uncertainty on stochastic pa... more ABSTRACT The Rosenblueth point estimator method is used to propagate uncertainty on stochastic parameters in a multi-ionic reactive transport model for concrete degradation. The degradation mechanism that was analysed is the ingress of chlorides into concrete. This point estimator method is used because it requires a minimum number of simulations to compute means, standard deviations and skewness for the solution of the transport model. Two exposure cases are considered in this article: the first is a saturated case, and the second is an unsaturated case with wetting (4 days) and drying (3 days at 50 % relative humidity) cycles. The sodium chloride exposure during the wetting cycle of both cases was 500 mmol/L. In both cases, predictions from the model were compared to experimental results. The Rosenblueth approach yielded results comparable to Monte Carlo simulations for both saturated and unsaturated cases. The relative sensitivity of model parameters on prediction results are investigated through a sensitivity analysis. The sensitivity results show the high importance of ionic diffusion parameters and of exposure conditions, while the calculated initial mineral phases in the hydrated paste have lower importance.
Materials and Structures, 2014
ABSTRACT Results of a statistical analysis of transport properties measurements carried out on a ... more ABSTRACT Results of a statistical analysis of transport properties measurements carried out on a number of concrete mixtures are presented. Migration and drying experiments were performed to evaluate the ionic diffusion coefficients and permeability of concrete mixtures. Seven concrete mixtures were tested. The mixtures were either batched under laboratory conditions or sampled from construction sites. For each mixture, approximately eighty concrete samples from a single batch were tested. Ionic diffusion coefficients were calculated by analyzing the evolution of the electrical current passing through concrete samples during the migration tests. Calculations took into account the volume of permeable pores of the materials and the pore solution chemistry. Permeability was calculated from mass loss measured during drying tests. The study indicates that the coefficient of variation of ionic diffusion coefficients is 11.1 % on average, with a maximum of 23.5 %, and that the coefficient of variation of permeability is 20.6 % on average, with a maximum of 37.3 %.
Journal of Materials in Civil Engineering, 2011
The present article assesses the use of sewage sludge as raw material in the ceramic industry, bu... more The present article assesses the use of sewage sludge as raw material in the ceramic industry, but specifically in the manufacture of soft‐mud bricks, to determine the maximum incorporation of sludge that results in technically sound and environmentally friendly bricks. The results ...
Journal of Bridge Engineering, 2012
International Journal of Reliability and Safety, 2009
Polytechnic Institute Montreal, PO Box 6079, Station Centre-ville, Main building, Room B336.8, Mo... more Polytechnic Institute Montreal, PO Box 6079, Station Centre-ville, Main building, Room B336.8, Montreal, QC H3C 3A7, Canada; EPFL MCS, Swiss Federal Institute of Technology (EPFL), Station 18 (bâtiment GC), CH-1015 Lausanne, Switzerland; Email: ...
Cement and Concrete Research, 2010
This article presents a comprehensive modeling of temperature, carbonation, water and chloride io... more This article presents a comprehensive modeling of temperature, carbonation, water and chloride ions transport in cover concrete using the transport model "TransChlor". The TransChlor transport model employs weather data and chloride ion concentrations present on the concrete surface to predict the temporal and spatial evolution of the presence of chloride ion concentrations in the cover concrete pores. The main features of the TransChlor model are presented and validated. The TransChlor model has been calibrated using experimental data on liquid water movement in concrete of different permeabilities under realistic microclimatic conditions. Chloride ion transport is validated by means of experimental results obtained from a newly developed chloride ion optical fiber based sensor.
Cement and Concrete Research, 2008
A numerical approach, named TransChlor, is proposed to simulate transport phenomena of various su... more A numerical approach, named TransChlor, is proposed to simulate transport phenomena of various substances in concrete. This approach is a theoretical model based on finite elements and finite differences methods. The model consists of coupled nonlinear partial differential equations based on Fick's diffusion law and on kinematics equations. Simulation results from a parametrical study highlight the influence of microclimatic conditions, exposure to deicing salts and concrete cover permeability and thickness on chloride ingress in concrete. The results show that the chloride ion concentration increases quickly in concrete cover when a structure is exposed to deicing salts at a mountainous location; whereas permeability of concrete cover is an insignificant parameter when the concrete is in direct or splash water contact.
mtq.gouv.qc.ca
La corrosion des barres d'armature est la première cause des interventions de remise en état sur ... more La corrosion des barres d'armature est la première cause des interventions de remise en état sur les ouvrages en béton armé. Dans le domaine des ouvrages d'art routiers, cette corrosion est initiée dans la majorité des cas par la présence de chlorures provenant des produits salants utilisés pour déneiger les routes en hiver. Alors que le phénomène de corrosion en présence d'ions chlorures est relativement bien connu, l'effet du microclimat et l'importance de l'exposition d'un élément en béton armé sur le transport des ions chlorures à travers le béton d'enrobage ne sont pas encore bien compris et modélisés.
Proceedings of the 4th …, 2002
ABSTRACT Two main factors govern the ingress of chloride ions into concrete reinforced with ordin... more ABSTRACT Two main factors govern the ingress of chloride ions into concrete reinforced with ordinary steel reinforcement, from de-icing salts: (1) the cover concrete (permeability, thickness), and (2) the microclimatic conditions (humidity, temperature, concentration of de-icing salts) at the concrete surface. A numerical model of chloride transport, taking into consideration environmental conditions (temperature, humidity, snow, rain and salt spreading), was used to predict the chloride profiles in concrete representative of that found in bridge element, for two types of exposure to water (splash, mist). This model was applied for two different regions in Switzerland: on the plateau in Lausanne, where there is a relatively mild winter climate and in the Alps where there is severe winter climate.
… for publication at Sixth …, 2003
ABSTRACT Two mains factors govern the ingress into reinforced concrete of the chloride ions provi... more ABSTRACT Two mains factors govern the ingress into reinforced concrete of the chloride ions provided by the de-icing salts: (1) the transport phenomena linked to the concrete quality and thickness, and (2) the microclimatic conditions (humidity, temperature, concentration of de-icing salts) on the concrete surface on the other hand. This study focuses on the influence of the local microclimatical conditions on chloride penetration into covercrete. A numerical model of chloride transport, taking into consideration the real environmental conditions, has been used to predict the chloride profiles for two different types of exposures (splash, mist) representative for bridges elements. The environmental conditions include representative variations of temperature and humidity, as well as snow, rain and salt spreading. This model was applied for two different regions in Switzerland: relatively mild winter climate (nearby Lake of Geneva) and severe winter climate in the Alps (Canton Graubünden). The results show the respective influences of both the concentration of de-icing salts and the local microclimate on the penetration of chloride ions into reinforced concrete. Moreover, the local exposure conditions appear to be the key factor in the calculations of reliable chloride profiles. This approach can be applied to any other geographical locations provided that the necessary climatological data are available.
Canadian Journal of Civil Engineering, 2009
Résumé : Les différentes zones d'un ouvrage d'art routier sont étudiées en fonction de ... more Résumé : Les différentes zones d'un ouvrage d'art routier sont étudiées en fonction de leur degré d'exposition au microclimat environnant. Les conditions climatiques provenant de stations météorologiques et la cinétique des véhicules permettent de définir des zones d'exposition aux produits ...
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Papers by David Conciatori