Raoul François | INSA Toulouse (original) (raw)

Papers by Raoul François

Research paper thumbnail of Modelling the response of prestressed beams with corroded reinforcement

European Journal of Environmental and Civil Engineering, 2009

Advances in the study of prestressed precast beams include the response of existing structures un... more Advances in the study of prestressed precast beams include the response of existing structures undergoing deterioration. The paper describes the behaviour of corroding prestressed structures, presenting a review of experimental results on the effects of corrosion on the prestressing reinforcement and the bond of corroded 7-wire strands in concrete. A numerical finite element model for the structural response of beams

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Research paper thumbnail of Modelling the Stiffness Reduction of Corroded Reinforced Concrete Beams after Cracking

Modelling of Corroding Concrete Structures, 2011

... Arnaud Castel1, Dario Coronelli2, Raoul François1 and David Cleland3 ... C. Andrade and G. Ma... more ... Arnaud Castel1, Dario Coronelli2, Raoul François1 and David Cleland3 ... C. Andrade and G. Mancini (eds.), Modelling of Corroding Concrete Structures, RILEM Bookseries 5, DOI 10.1007/978-94-007-0677-4_15, © RILEM 2011 219 Page 2. Arnaud Castel et al. 220 ...

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Research paper thumbnail of Mechanical Behavior of Long-Term Corroded Reinforced Concrete Beam

Modelling of Corroding Concrete Structures, 2011

Abstract. This paper presents both experimental results and modelling of a highly corroded beam s... more Abstract. This paper presents both experimental results and modelling of a highly corroded beam subjected to chloride environment to assess the performance of long-term corrosion damaged beams. A 26 year old corroded reinforced concrete beam exposed to chloride ...

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Research paper thumbnail of Influence of steel-concrete interface defects owing to the top-bar effect on the chloride-induced corrosion of reinforcement

Magazine of Concrete Research, 2011

ABSTRACT This paper deals with the influence of the steel-concrete interface condition on the rei... more ABSTRACT This paper deals with the influence of the steel-concrete interface condition on the reinforcement corrosion in a chloride environment. Two large-sized concrete members were cast including horizontal reinforcements at different levels in order to create voids under the upper horizontal bars caused by the well-known `top-bar effect'. The walls were then sawn into small-sized specimens including one rebar. These small specimens were submitted to wetting-drying cycles in salt water (natural corrosion process). The polarisation resistance technique was performed to monitor the steel corrosion during the ageing up to 55 weeks. Chloride profiles were regularly measured and specimens were broken to observe the corrosion pattern. Results show that, first, a good-quality steel-concrete interface significantly reduces the corrosion rate in comparison with the specimen with interfacial defects. Second, before concrete cracking, the corrosion pattern observed is completely different between the specimens with or without defect. Perfect interface specimens show a typical local pitting corrosion pattern owing to chloride attack. However, specimens affected by the `top-bar effect' show a generalised corrosion along the steel surface affected by the void (surface under the horizontal steel bars in regard to concrete casting direction). Macrocell corrosion seems to develop between the lower surface affected by the void acting as an anode and the upper surface where the bond is perfect as the cathode. The concrete cracking is delayed for specimens affected by the `top-bar effect' in spite of a higher corrosion rate. This delay can be attributed to the time necessary for the rust to fill the voids.

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Research paper thumbnail of Characterization of Steel/Concrete Interface For a Long-Term Corroded Beam Stored in Chloride Environment

Advances in Structures, Pts 1-5, 2011

... In addition, it is well-known that the Raman technique is used to analyze the compound in a v... more ... In addition, it is well-known that the Raman technique is used to analyze the compound in a very local area, which much depended on ... [4] WJ Chitty, P. Dillmann, V. L'Hostis, C. Lombard: Corrosion Science, 47(2005), pp 1555-1581 [5] Wong HS, Zhao YX, Karimi AR, Buenfeld ...

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Research paper thumbnail of Study of the impact of localised cracks on the corrosion mechanism

European Journal of Environmental and Civil Engineering, 2012

Corrosion is one of the major problems that the reinforced concrete industry is facing nowadays. ... more Corrosion is one of the major problems that the reinforced concrete industry is facing nowadays. Much research has been carried out to investigate the influence of cracks on rebar corrosion. In this project ring shaped mortar samples with an 8mm steel bar inside were cracked with different crack widths and then subjected to continuous wetting and drying cycles in salt

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Research paper thumbnail of Structural performance of a 26-year-old corroded reinforced concrete beam

European Journal of Environmental and Civil Engineering, 2012

This article presents experimental results and the modelling of a highly corroded beam subjected ... more This article presents experimental results and the modelling of a highly corroded beam subjected to a chloride environment to assess the performance of long-term-corrosion-damaged beams. A reinforced concrete beam corroded by 26 years of exposure to a chloride environment was tested until failure, as was a control beam of the same age. Cracking maps and corrosion maps were drawn for

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Research paper thumbnail of Response of corroded prestressed beams with bonded strands

Proceedings of the Institution of Civil Engineers-Structures and Buildings, 2012

ABSTRACT Deterioration of post-tensioned structures may take place as a consequence of severe env... more ABSTRACT Deterioration of post-tensioned structures may take place as a consequence of severe environmental conditions or design or construction errors. This paper investigates analytically the effects of corrosion on the structural response of bonded post-tensioned beams. An experimental study on the stress corrosion of prestressing wires is described first, providing data on the steel behaviour. A series of tests on beams taken from the literature is then analysed. The breaking of a part of the wires was caused by artificial corrosion; the beams showed stiffness and strength deterioration as a consequence of further breakages occurring under imposed load. Two different analytical approaches are used: macro finite-element analysis based on the calculation of the cross-section response and nonlinear finite-element analysis. The analyses provide the global response and local strain values with the interpretation of the causes of the deterioration of the response.

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Research paper thumbnail of Concrete cracking due to chloride-induced reinforcement corrosion - influence of steel-concrete interface defects due to the 'top-bar effect

European Journal of Environmental and Civil Engineering, 2012

This article deals with the influence of the steel–concrete interface condition on reinforcement ... more This article deals with the influence of the steel–concrete interface condition on reinforcement corrosion and concrete cracking in a chloride environment. Four large concrete members were cast with horizontal reinforcements at different levels in order to create voids under the upper horizontal bars due to the well-known ‘top-bar effect.’ Then, the members were sawn into smaller specimens that included one

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Research paper thumbnail of Optimisation des structures en béton armé vis-à-vis de la corrosion

Revue Française de Génie Civil, 1998

This paper deals with the strategy of service-life prediction of reinforced concrete structures. ... more This paper deals with the strategy of service-life prediction of reinforced concrete structures. This strategy which is based on a model of the reinforcement corrosion process, can be used alone to calculate the residual service-life or linked with maintenance method to increase this service life.

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Research paper thumbnail of Analysis of progressive damage to reinforced ordinary and high performance concrete in relation to loading

Materials and Structures, 1998

This paper deals with the effect of loading on the microstructure of reinforced high performance ... more This paper deals with the effect of loading on the microstructure of reinforced high performance and normal concrete. In the case of reinforced concrete structures, cracking is the only visible sign of mechanical degradation and is accompanied by microscopic damage to the concrete. To account for this damage, experiments on three different concretes with compressive strengths (f c28) of 45 MPa, 80 MPa and 100 MPa were carried out. The loadless initial state of concrete and the damage state after loading were described using the single replica technique observed on SEM. The way in which the microcracks extended was revealed, with predominantly aggregated bond failure and crack branching occurring with cracks spreading out around the coarse aggregate under stable progressive fracture conditions. An increase in the specific area of microcracks was seen to result from an increase in load. This phenomenon could have an influence on the durability properties of reinforced concrete structures.

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Research paper thumbnail of Méthode d'étude mécanique et physico-chimique de l'interface acier-béton

Materials and Structures, 1993

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Research paper thumbnail of Aging damage model of concrete behavior during the leaching process

Materials and Structures, 1997

This paper deals with the effect of the leaching process of cement-based materials on their mecha... more This paper deals with the effect of the leaching process of cement-based materials on their mechanical properties. This process mainly induces a total leaching of Ca(OH)2 and a progressive decalcification of the C-S-H leading in turn to a gradient of C/S ratio in the leaching zone. Modeling of the deterioration of cement paste exposed to leaching consists of a decrease

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Research paper thumbnail of Mechanical behaviour of corroded reinforced concrete beams—Part 1: Experimental study of corroded beams

Materials and Structures, 2000

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Research paper thumbnail of Serviceability Limit State criteria based on steel–concrete bond loss for corroded reinforced concrete in chloride environment

Materials and Structures, 2009

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Research paper thumbnail of Effective Tension Active Cross-Section of Reinforced Concrete Beams After Cracking

Materials and Structures, 2007

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Research paper thumbnail of Effects of Bar-Placement Conditions on Steel-Concrete Bond

Materials and Structures, 2007

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Research paper thumbnail of Measurement and modeling of gas transfer in cracked mortars

Materials and Structures, 2005

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Research paper thumbnail of Effect of crack opening on carbon dioxide penetration in cracked mortar samples

Materials and Structures, 2009

ABSTRACT

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Research paper thumbnail of Repairing corroded RC beam with near-surface mounted CFRP rods

Materials and Structures, 2011

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Research paper thumbnail of Modelling the response of prestressed beams with corroded reinforcement

European Journal of Environmental and Civil Engineering, 2009

Advances in the study of prestressed precast beams include the response of existing structures un... more Advances in the study of prestressed precast beams include the response of existing structures undergoing deterioration. The paper describes the behaviour of corroding prestressed structures, presenting a review of experimental results on the effects of corrosion on the prestressing reinforcement and the bond of corroded 7-wire strands in concrete. A numerical finite element model for the structural response of beams

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Modelling the Stiffness Reduction of Corroded Reinforced Concrete Beams after Cracking

Modelling of Corroding Concrete Structures, 2011

... Arnaud Castel1, Dario Coronelli2, Raoul François1 and David Cleland3 ... C. Andrade and G. Ma... more ... Arnaud Castel1, Dario Coronelli2, Raoul François1 and David Cleland3 ... C. Andrade and G. Mancini (eds.), Modelling of Corroding Concrete Structures, RILEM Bookseries 5, DOI 10.1007/978-94-007-0677-4_15, © RILEM 2011 219 Page 2. Arnaud Castel et al. 220 ...

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Research paper thumbnail of Mechanical Behavior of Long-Term Corroded Reinforced Concrete Beam

Modelling of Corroding Concrete Structures, 2011

Abstract. This paper presents both experimental results and modelling of a highly corroded beam s... more Abstract. This paper presents both experimental results and modelling of a highly corroded beam subjected to chloride environment to assess the performance of long-term corrosion damaged beams. A 26 year old corroded reinforced concrete beam exposed to chloride ...

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Research paper thumbnail of Influence of steel-concrete interface defects owing to the top-bar effect on the chloride-induced corrosion of reinforcement

Magazine of Concrete Research, 2011

ABSTRACT This paper deals with the influence of the steel-concrete interface condition on the rei... more ABSTRACT This paper deals with the influence of the steel-concrete interface condition on the reinforcement corrosion in a chloride environment. Two large-sized concrete members were cast including horizontal reinforcements at different levels in order to create voids under the upper horizontal bars caused by the well-known `top-bar effect'. The walls were then sawn into small-sized specimens including one rebar. These small specimens were submitted to wetting-drying cycles in salt water (natural corrosion process). The polarisation resistance technique was performed to monitor the steel corrosion during the ageing up to 55 weeks. Chloride profiles were regularly measured and specimens were broken to observe the corrosion pattern. Results show that, first, a good-quality steel-concrete interface significantly reduces the corrosion rate in comparison with the specimen with interfacial defects. Second, before concrete cracking, the corrosion pattern observed is completely different between the specimens with or without defect. Perfect interface specimens show a typical local pitting corrosion pattern owing to chloride attack. However, specimens affected by the `top-bar effect' show a generalised corrosion along the steel surface affected by the void (surface under the horizontal steel bars in regard to concrete casting direction). Macrocell corrosion seems to develop between the lower surface affected by the void acting as an anode and the upper surface where the bond is perfect as the cathode. The concrete cracking is delayed for specimens affected by the `top-bar effect' in spite of a higher corrosion rate. This delay can be attributed to the time necessary for the rust to fill the voids.

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Research paper thumbnail of Characterization of Steel/Concrete Interface For a Long-Term Corroded Beam Stored in Chloride Environment

Advances in Structures, Pts 1-5, 2011

... In addition, it is well-known that the Raman technique is used to analyze the compound in a v... more ... In addition, it is well-known that the Raman technique is used to analyze the compound in a very local area, which much depended on ... [4] WJ Chitty, P. Dillmann, V. L'Hostis, C. Lombard: Corrosion Science, 47(2005), pp 1555-1581 [5] Wong HS, Zhao YX, Karimi AR, Buenfeld ...

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Research paper thumbnail of Study of the impact of localised cracks on the corrosion mechanism

European Journal of Environmental and Civil Engineering, 2012

Corrosion is one of the major problems that the reinforced concrete industry is facing nowadays. ... more Corrosion is one of the major problems that the reinforced concrete industry is facing nowadays. Much research has been carried out to investigate the influence of cracks on rebar corrosion. In this project ring shaped mortar samples with an 8mm steel bar inside were cracked with different crack widths and then subjected to continuous wetting and drying cycles in salt

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Structural performance of a 26-year-old corroded reinforced concrete beam

European Journal of Environmental and Civil Engineering, 2012

This article presents experimental results and the modelling of a highly corroded beam subjected ... more This article presents experimental results and the modelling of a highly corroded beam subjected to a chloride environment to assess the performance of long-term-corrosion-damaged beams. A reinforced concrete beam corroded by 26 years of exposure to a chloride environment was tested until failure, as was a control beam of the same age. Cracking maps and corrosion maps were drawn for

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Response of corroded prestressed beams with bonded strands

Proceedings of the Institution of Civil Engineers-Structures and Buildings, 2012

ABSTRACT Deterioration of post-tensioned structures may take place as a consequence of severe env... more ABSTRACT Deterioration of post-tensioned structures may take place as a consequence of severe environmental conditions or design or construction errors. This paper investigates analytically the effects of corrosion on the structural response of bonded post-tensioned beams. An experimental study on the stress corrosion of prestressing wires is described first, providing data on the steel behaviour. A series of tests on beams taken from the literature is then analysed. The breaking of a part of the wires was caused by artificial corrosion; the beams showed stiffness and strength deterioration as a consequence of further breakages occurring under imposed load. Two different analytical approaches are used: macro finite-element analysis based on the calculation of the cross-section response and nonlinear finite-element analysis. The analyses provide the global response and local strain values with the interpretation of the causes of the deterioration of the response.

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Research paper thumbnail of Concrete cracking due to chloride-induced reinforcement corrosion - influence of steel-concrete interface defects due to the 'top-bar effect

European Journal of Environmental and Civil Engineering, 2012

This article deals with the influence of the steel–concrete interface condition on reinforcement ... more This article deals with the influence of the steel–concrete interface condition on reinforcement corrosion and concrete cracking in a chloride environment. Four large concrete members were cast with horizontal reinforcements at different levels in order to create voids under the upper horizontal bars due to the well-known ‘top-bar effect.’ Then, the members were sawn into smaller specimens that included one

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Optimisation des structures en béton armé vis-à-vis de la corrosion

Revue Française de Génie Civil, 1998

This paper deals with the strategy of service-life prediction of reinforced concrete structures. ... more This paper deals with the strategy of service-life prediction of reinforced concrete structures. This strategy which is based on a model of the reinforcement corrosion process, can be used alone to calculate the residual service-life or linked with maintenance method to increase this service life.

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Analysis of progressive damage to reinforced ordinary and high performance concrete in relation to loading

Materials and Structures, 1998

This paper deals with the effect of loading on the microstructure of reinforced high performance ... more This paper deals with the effect of loading on the microstructure of reinforced high performance and normal concrete. In the case of reinforced concrete structures, cracking is the only visible sign of mechanical degradation and is accompanied by microscopic damage to the concrete. To account for this damage, experiments on three different concretes with compressive strengths (f c28) of 45 MPa, 80 MPa and 100 MPa were carried out. The loadless initial state of concrete and the damage state after loading were described using the single replica technique observed on SEM. The way in which the microcracks extended was revealed, with predominantly aggregated bond failure and crack branching occurring with cracks spreading out around the coarse aggregate under stable progressive fracture conditions. An increase in the specific area of microcracks was seen to result from an increase in load. This phenomenon could have an influence on the durability properties of reinforced concrete structures.

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Méthode d'étude mécanique et physico-chimique de l'interface acier-béton

Materials and Structures, 1993

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Aging damage model of concrete behavior during the leaching process

Materials and Structures, 1997

This paper deals with the effect of the leaching process of cement-based materials on their mecha... more This paper deals with the effect of the leaching process of cement-based materials on their mechanical properties. This process mainly induces a total leaching of Ca(OH)2 and a progressive decalcification of the C-S-H leading in turn to a gradient of C/S ratio in the leaching zone. Modeling of the deterioration of cement paste exposed to leaching consists of a decrease

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Mechanical behaviour of corroded reinforced concrete beams—Part 1: Experimental study of corroded beams

Materials and Structures, 2000

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Serviceability Limit State criteria based on steel–concrete bond loss for corroded reinforced concrete in chloride environment

Materials and Structures, 2009

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Effective Tension Active Cross-Section of Reinforced Concrete Beams After Cracking

Materials and Structures, 2007

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Effects of Bar-Placement Conditions on Steel-Concrete Bond

Materials and Structures, 2007

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Measurement and modeling of gas transfer in cracked mortars

Materials and Structures, 2005

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Effect of crack opening on carbon dioxide penetration in cracked mortar samples

Materials and Structures, 2009

ABSTRACT

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Research paper thumbnail of Repairing corroded RC beam with near-surface mounted CFRP rods

Materials and Structures, 2011

Bookmarks Related papers MentionsView impact