References of "Courard, Luc"
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See detailDetection of Defects in Concrete With Ground Penetrating Radar
Van der Wielen, Audrey ULg; Courard, Luc ULg; Nguyen, Frédéric ULg

in ESPSC 2011: European Symposium on Polymers in Sustainable Construction (Czarnecki Symposium) (2011, September)

Ground Penetrating Radar (GPR) is a nondestructive technique particularly well adapted to the inspection of concrete structures and can help to determine the structure inner geometry or to detect damaged ... [more ▼]

Ground Penetrating Radar (GPR) is a nondestructive technique particularly well adapted to the inspection of concrete structures and can help to determine the structure inner geometry or to detect damaged areas. When the GPR is used on structures containing thin layers, for example the sealing layer of a bridge or the void into a masonry wall, it is important for the radar user to know the minimum thickness required to detect and estimate the thickness of those layers. The theory of thin layer detection is based on a sine wave but, in reality, the GPR emits a complicated pulse, which undergoes attenuation into the layer. To see the influence of those realistic conditions on the reflection coefficient of a thin layer, we combined experimental measurements and numerical FDTD simulations. The experimental results matched the numerical predictions well, presenting a fast attenuation compared to the theoretical predictions. Nevertheless, for thicknesses inferior to λ/11, the reflection coefficient could still be considered as linearly dependent of the thickness to wavelength ratio. [less ▲]

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See detailHistoire des ouvrages religieux en béton en province de Liège: état des lieux et pathologies
Courard, Luc ULg; Gillard, Anne; Paquet, Pierre ULg

Scientific conference (2011, July 08)

Élément clé de l'évolution architecturale, le béton armé a participé à l'évolution de l'architecture religieuse catholique en particulier. Depuis sa découverte au XIXe siècle, ce matériau inventé ... [more ▼]

Élément clé de l'évolution architecturale, le béton armé a participé à l'évolution de l'architecture religieuse catholique en particulier. Depuis sa découverte au XIXe siècle, ce matériau inventé, économique et résistant au feu, a cependant montré ses limites: fissures, épaufrures, désintégration. Il paraît donc nécessaire de s'inquiéter de l'état actuel des églises, témoins de l'évolution architecturale, mais aussi points de repère d'un quartier ou d’un village. Dans l'arrondissement de Liège, neuf églises paroissiales en béton ont été identifiées. Pour chacune d'entre elles, une inspection visuelle a été menée. Cet examen visuel, qui ne constitue qu'une première étape dans une démarche de restauration ou de rénovation, a été précédé de recherches documentaires destinées à connaître l'histoire des églises et à ainsi mieux comprendre leur état. Cet article s'intéresse à une église de Liège, en particulier : l'église Saint-Vincent, située à l'entrée de la ville. Construite en vingt mois à peine, de 1928 à 1930, cet édifice monumental montre actuellement des épaufrures, des fissures et des traces d'humidité. L'inspection visuelle, ainsi que les essais en laboratoire et l'examen au radar qui ont suivi, ont permis d'émettre des hypothèses quant aux dégradations qui affectent cet édifice à la qualité architecturale reconnue. [less ▲]

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See detailTechniques d’analyse de cycle de vie appliquées aux structures
Rossi, Barbara ULg; Courard, Luc ULg

in Waldmann, Danièle; Lecomte, André; Courard, Luc (Eds.) Compte rendu des Journées scientifiques du Regroupement francophone pour la recherche et la formation sur le béton: RF2B, Luxembourg 7-8 juillet 2011 (2011, July)

L’analyse de cycle de vie (ACV) est de plus en plus utilisée afin d’évaluer les impacts environnementaux liés à la production, la mise en œuvre, l’utilisation, la mise en décharge ou le recyclage de ... [more ▼]

L’analyse de cycle de vie (ACV) est de plus en plus utilisée afin d’évaluer les impacts environnementaux liés à la production, la mise en œuvre, l’utilisation, la mise en décharge ou le recyclage de produits, en incluant les matières premières à partir desquelles ces produits sont faits. L’intérêt de l’ACV a déjà été démontré dans le domaine de la construction et plus particulièrement pour les bâtiments. Les méthodologies actuelles sont, par ailleurs, assez bien définies, notamment par l’intermédiaire des normes ISO. Cependant, même si ses applications sont nombreuses dans ce domaine, elle souffre encore de lacunes. Cet article donne un aperçu bref des ACV réalisées dans le domaine des bâtiments et décrit, par ailleurs, les résultats d’une ACV appliquée à une structure portante dans le cas où cette structure est faite de deux matériaux différents : l’acier et le béton. [less ▲]

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See detailInfluence des composants des interfaces béton - agent démoulant - coffrage sur l'aspect des parements en béton
Courard, Luc ULg; Martin, Marie

Scientific conference (2011, March 24)

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See detailGPR Limits for Thin Layers in Concrete Detection: Numerical and Experimental Evaluation
Van der Wielen, Audrey ULg; Courard, Luc ULg; Nguyen, Frédéric ULg

in Progress In Electromagnetics Research Symposium Proceedings, Marrakesh, Morocco, March 20-23, 2011 (2011, March)

The Ground Penetrating Radar (GPR) is a nondestructive technique increasingly used in civil structures inspection. In those structures, thin layers, presenting a relatively small thickness compared to ... [more ▼]

The Ground Penetrating Radar (GPR) is a nondestructive technique increasingly used in civil structures inspection. In those structures, thin layers, presenting a relatively small thickness compared to their area, are common and induce a complex multiple reflection scheme of the GPR waves on the two interfaces limiting the layer. The theoretical relationships predicting the reflected amplitude are based on multiple simplifying assumptions that are not matched by most commercial GPR impulse machines. In the first part of this study, we confronted the theoretical curves with numerical finite difference simulations performed with GprMax2D, with both a continuous sine wave and a realistic pulse derived from measurements. In the second part, we performed experiments on two concrete slabs, separated with an air space of variable thickness. The measured amplitude appeared to be different from the predictions, probably due to surface noise. [less ▲]

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See detailGeosynthetics: materials, design, durability and application
Courard, Luc ULg

in Application des géosynthétiques dans la géotechnique (2011, January 26)

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See detailSurfology Based Concrete Repair Engineering
Courard, Luc ULg; Michel, Frédéric ULg; Garbacz, Andrzej et al

in Polymers in sustainable construction (2011)

Research projects performed at the University of Liege and the Warsaw University of Technology have pointed out the importance of taking care about surfology of materials: if durability also means ... [more ▼]

Research projects performed at the University of Liege and the Warsaw University of Technology have pointed out the importance of taking care about surfology of materials: if durability also means sustainability, we may then consider that optimization in material selection is essential for repair efficient. Surfology contributes to understand what will make the contact effective or not, and allow interactions of variable intensities between the materials. Different scales of observation – micro to macro - are needed to exactly represent what happens when materials are put into contact. [less ▲]

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See detailMicrostructure and durability of mortars modified with medium active blast furnace slag
Hadj Sadok, Ahmed; Kenaï, Saïd; Courard, Luc ULg et al

in Construction & Building Materials (2011), 25(2), 1018-1025

Mechanical characteristics and durability properties of blast furnace slag cement composites largely depend on the hydraulic activity of the slag. In this paper, a Granulated Blast Furnace Slag with a low ... [more ▼]

Mechanical characteristics and durability properties of blast furnace slag cement composites largely depend on the hydraulic activity of the slag. In this paper, a Granulated Blast Furnace Slag with a low reactivity index is used in modifying mortar composition. Microstructure and durability of mixes containing 0%, 30% and 50% of slag as substitution to OPC are respectively compared and analyzed. Water porosity, Mercury Intrusion Porosity and pore size distribution are studied after 28, 90 and 360 days of wet curing. A qualitative microstructure analysis of mortars is proposed with Scanning Electron Microscope (SEM). The durability of mortar is evaluated through capillary water absorption and chloride diffusion tests. The results indicate a finer porosity and lower water absorption for slag mortars at old ages (90 and 360 days). Moreover, lower chloride diffusion for 50% blast furnace slag substitution is observed. [less ▲]

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See detailPerméabilité au gaz et aux ions chlore des mortiers à base de laitier de faible hydraulicité
Hadj Sadok, Ahmed; Kenaï, Saïd; Courard, Luc ULg

in Innovation et Valorisation dans le génie civil et les matériaux de construction (2011)

La durabilité des bétons au laitier de haut fourneau dépend fortement de l’activité hydraulique du laitier. Dans cette étude, un laitier algérien, caractérisé par une faible hydraulicité, est utilisé dans ... [more ▼]

La durabilité des bétons au laitier de haut fourneau dépend fortement de l’activité hydraulique du laitier. Dans cette étude, un laitier algérien, caractérisé par une faible hydraulicité, est utilisé dans la fabrication de mortiers comme substituant du ciment à des taux de 0, 30 et 50%. En plus d’une caractérisation mécanique, l’effet du laitier sur la durabilité des mortiers est évalué par des essais de perméabilité à l’oxygène, de diffusion de chlorures en régime permanent ainsi que de conduction des ions chlore (essai accéléré ASTM). Les résultats montrent, malgré une faible réactivité du laitier, une amélioration de la perméabilité à l’oxygène à long terme (360 jours) pour les mortiers au laitier, particulièrement pour un taux de 50%. La présence du laitier réduit la perméabilité aux ions chlore, d’une part, en augmentant le temps de passage des chlorures à travers le mortier et, d’autre part, en diminuant le taux de diffusion. Par ailleurs, une faible conduction des chlorures est observée pour les mortiers au laitier, montrant une similitude avec les résultats d’essai de diffusion en régime permanent. [less ▲]

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See detailChurches and concrete in Liège district: history, architecture and pathologies
Courard, Luc ULg; Paquet, Pierre ULg; Gillard, Anne

in Restoration of Buildings and Monuments = Bauinstandsetzen und Baudenkmalpflege (2011), 17(1), 314

Reinforced concrete is a key element of the architectural evolution and has been specifically involved in the development of religious architecture. Since its discovery in the nineteenth century, this ... [more ▼]

Reinforced concrete is a key element of the architectural evolution and has been specifically involved in the development of religious architecture. Since its discovery in the nineteenth century, this invented material, economic and fire resistant, however showed its limits: cracks, spalling and disintegration are some of the degradations we may observe today. It therefore seems necessary to worry about the current state of churches: these monuments are indeed the testimony of architectural evolution but also landmarks for the neighborhood. In Liege district, Belgium, nine parish churches have been identified as mainly concrete based. For each church, a visual inspection has been realized: this overview let us to make an assessment of the monument, with regard to concrete and reinforced concrete situation. This inspection is the first step for further investigations included into a restoration or renovation process. [less ▲]

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See detailMineralization of bio-based materials: effect on cement-based mix properties
Courard, Luc ULg; Darimont, Anne ULg; Louis, Arnaud ULg et al

in Bulletin of the Polytechnic Institute of Jassy, Construction. Architecture Section (2011), LIV(LVIII),

The lightweight concrete with bio-based products knows an interesting development in the construction field, especially as thermal insulation panels for walls in buildings. Before identifying and ... [more ▼]

The lightweight concrete with bio-based products knows an interesting development in the construction field, especially as thermal insulation panels for walls in buildings. Before identifying and quantifying the basic physical characteristics of concrete made from wood, miscanthus, hemp or bamboo (acoustic and thermal properties in particular), it is necessary to optimize the composition of the product. It is clear that the final product is not unique and a compromise has to be found between insulation and mechanical properties. The long term stability as well as the reinforcement may be obtained by means of a mineralization process of the natural product: a preparation with a lime and/or cement-based material is necessary to reinforce the cohesion of the bio-based product. Optical and SEM analysis helped to clearly understand the interactions between the bio-based fibrous material and the cementitious materials, the quality of the bond and their effects on the properties of the cement-based concrete products. [less ▲]

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See detailConstructions: matériaux et pathologies
Courard, Luc ULg

Learning material (2011)

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See detailTransport properties of nano-clay modified hydrophobic concrete
Di Maio, Luciano; Fariello, Maria Letizia; Scarfato, P. et al

in The new boundaries of strutural concrete (2011)

In this work the performance of a traditional concrete modified by the addition of nanoparticles and of a hydrophobic resin were studied. In particular, water capillary suction, water absorption at ... [more ▼]

In this work the performance of a traditional concrete modified by the addition of nanoparticles and of a hydrophobic resin were studied. In particular, water capillary suction, water absorption at atmospheric pressure and under vacuum, chloride diffusion, sulphates resistance and carbonation rate tests were carried out. The nanocomposite concrete (hydrophobic and not hydrophobic) shows efficacy in inhibiting the water absorption and CO2 transport thanks to the internal microstructure modification induced by the nanoparticles action which makes more difficult the passage of the substances. Hydrophobic concrete, instead, very effectively avoids the water inlet, but, because of its hydrophobic character, makes the pores of concrete unsatured of water and the CO2 can diffuse faster through the concrete bulk. [less ▲]

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See detailQuality assurance in repairing industrial floors: parameters and recommendations
Courard, Luc ULg; Bissonnette, Benoît

in Zajc, A.; Sustercic, J. (Eds.) Moznot Pocenitive Izvajanja Betonarskih Del (2011)

Since concrete has been used for more than a century, many structures need repair in different degrees and others need strengthening to withstand higher loads. Moreover, the number of new concrete ... [more ▼]

Since concrete has been used for more than a century, many structures need repair in different degrees and others need strengthening to withstand higher loads. Moreover, the number of new concrete structures is constantly increasing, and therefore repair or retrofitting requirements increase. Present concerns of sustainable development emphasizing repair or strengthening instead of new construction, acts as incentive to this trend. The bonded overlay technique is particularly suitable in the case of structures with large areas like industrial floors. This paper has the ambition to present reliable design methodology for the practitioner. Surface preparation, overlay design and material selection, application process and QC/QA are discussed and guidelines are proposed in order to enhance quality of repair operations. [less ▲]

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See detailSaturation level of the superficial zone of concrete and adhesion of repair systems
Courard, Luc ULg; Lenaers, Jean-François; Michel, Frédéric ULg et al

in Construction & Building Materials (2011), 25((5)), 2488-2494

Appropriate surface saturation level is essential for the durability of the repaired structure. The repair material is often blamed for ‘‘not sticking’’, although the general source of the trouble lies ... [more ▼]

Appropriate surface saturation level is essential for the durability of the repaired structure. The repair material is often blamed for ‘‘not sticking’’, although the general source of the trouble lies with the substrate surface conditioning. An extensive research project has been undertaken to develop specifications and performance criteria for surface preparation of concrete substrates. A field test was developed to evaluate the optimum moisture conditioning of the substrate concrete prior to application of repair material; this has been calibrated and compared with destructive and non-destructive on three types of concrete and two types of surface preparation. In order to evaluate different saturation levels, concrete samples have been stored in more than 12 modes of conservation. Finally, repair mortars have been applied on concrete substrates and adhesion was measured for different concrete surface saturation levels. Initial Surface Absorption Test (ISAT) can be used as an attractive quantitative test to evaluate saturation level of concrete substrate. Moreover, it is clearly shown that saturation levels higher than 50% and lower than 90% are requested for promoting adhesion of PCC mortars. [less ▲]

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See detailBonded cement-based material overlays for the repair, the lining or the strengthening of slabs and pavements
Bissonnette, Benoît; Courard, Luc ULg; Fowler, David et al

Book published by Springer (2011)

1.0 INTRODUCTION 2.0 OVERLAY DESIGN PROCESS 3.0 CONDITION EVALUATION OF THE EXISTING STRUCTURE PRIOR TO OVERLAY 4.0 BOND 5.0 STRUCTURAL BEHAVIOUR 6.0 DEBONDING 7.0 DESIGN 8.0 PRACTICE AND QUALITY ... [more ▼]

1.0 INTRODUCTION 2.0 OVERLAY DESIGN PROCESS 3.0 CONDITION EVALUATION OF THE EXISTING STRUCTURE PRIOR TO OVERLAY 4.0 BOND 5.0 STRUCTURAL BEHAVIOUR 6.0 DEBONDING 7.0 DESIGN 8.0 PRACTICE AND QUALITY ASSURANCE 9.0 MAINTENANCE AND REPAIR OF OVERLAYS 10.0 CONCLUSION [less ▲]

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See detailBond (chapter 4)
Silfwerbrand, Johan; Beushausen, Hans; Courard, Luc ULg

in Bissonnette, Benoît; Courard, Luc; Fowler, David (Eds.) et al Bonded cement-based material overlays for the repair, the lining or the strengthening of slabs and pavements (2011)

Good bond is a key factor for providing monolithic action in bonded concrete overlays. This chapter starts with three theoretical sections classifying bond in three groups (complete, uncertain, and poor ... [more ▼]

Good bond is a key factor for providing monolithic action in bonded concrete overlays. This chapter starts with three theoretical sections classifying bond in three groups (complete, uncertain, and poor), defining bond strength, and describing the fundamental bond mechanisms. The main part of this chapter covers a thorough description in chronological order of how the 13 most important factors affect bond. All events from removal of deteriorated concrete to concrete placing and curing and long-term exposure are investigated. There exist a number of different methods to determine bond strength and the most frequent ones are briefly described in a separate section. It is shown that there is an evident relationship between the two most frequently used families of test methods, i.e., between methods determining bond strength in tension and bond strength in shear. Furthermore, it is shown that it is possible to provide durable bond in concrete overlays if all operations for concrete removal, surface cleaning, concrete placing, and curing are conducted meticulously. The chapter is ended by two sections devoted to design strength values in various international codes and performance requirements that can be used for quality control. [less ▲]

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See detailCondition evaluation of the existing structure prior to overlay (chapter 3)
Courard, Luc ULg; Trevino, Manuel; Bissonnette, Benoît

in Bissonnette, Benoît; Courard, Luc; Fowler, David (Eds.) et al Bonded cement-based material overlays for the repair, the lining or the strengthening of slabs and pavements (2011)

The knowledge and analysis of the causes of degradations is the first step in repairing existing concrete structures. The assessment is performed by using destructive and non destructive methods. These ... [more ▼]

The knowledge and analysis of the causes of degradations is the first step in repairing existing concrete structures. The assessment is performed by using destructive and non destructive methods. These allow detecting modification of physical, chemical and/or mechanical properties of concrete: cracking, deformation, spalling, carbonation, etc., are various causes of distress, with potential irreversible consequences on concrete structure behaviour. A description of specific methods for pavements and structural slabs is proposed; it is usually recommended to combine complementary methods for efficient diagnosis. This chapter wants to offer an overview of techniques and references that could help the user in selecting the most appropriate investigation program. [less ▲]

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