References of "Courard, Luc"
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See detailEclatement du béton dû à granulats contaminés à la chaux vive
Courard, Luc ULg; Darimont, Anne ULg; Degée, Hervé ULg

Article for general public (2011)

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See detailConcrete Repair Science: new trends - 10 Years cooperation between the University of Liège and the Politechnika Warsawska
Courard, Luc ULg; Garbacz, Andrzej

Book published by Université de Liège (2010)

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See detailSurfology: new investigations techniques and approaches
Courard, Luc ULg; Garbacz, Andrzej

Scientific conference (2010, November 29)

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See detailRecherche dans le domaine du béton à l'Université de Liège (2009-2010)
Dotreppe, Jean-Claude ULg; Franssen, Jean-Marc ULg; Somja, H. et al

Scientific conference (2010, October 21)

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See detailParticle packing of concrete containing blended cement
He, Huan ULg; Courard, Luc ULg; Pirard, Eric ULg

Conference (2010, September 20)

Physical particle packing is becoming a hot topic in concrete technology as more and more types of granular materials are used in concrete either for ecological or for engineering purposes. Aggregate is ... [more ▼]

Physical particle packing is becoming a hot topic in concrete technology as more and more types of granular materials are used in concrete either for ecological or for engineering purposes. Aggregate is used as concrete’s skeleton, whereby the particles are stabilized by the cementitious matrix. Packing efficiency governs the spatial characteristics of this structure and thereby influences concrete’s properties. Fine-grained sand can be used to further improve density of the aggregate structure. The particulate cement is also frequently blended by fine mineral admixtures to influence performance of the paste and the properties of the matured concrete. The so-called filler effects increase packing density of the blended cement and possibly reduce water demand. High performance characteristics require suitable blending materials of proper properties (fineness, shape, chemical components, etc.). A number of theoretical packing models have been proposed for prediction of packing characteristics and the resulting concrete properties. A minimum voids ratio has been mathematically derived for certain particle size distributions. This allowed establishment of some optimum graded mixtures for concrete production. On the other hand, the computer simulation approach provides a powerful tool for simulating particle packing. Computational concrete (compucrete) has been developed for a wide range of research purposes. Application of computer simulation to particle packing offers a promising perspective in concrete technology; it provides a proper representation of the heterogeneous concrete material, and renders the possibility of studying the effects of a wide range of technological parameters. In this study, an advanced DEM will be utilized for investigate the packing properties of admixtures blended cement. This new-developed system is capable of packing simulations of arbitrary-shaped particles. Experimental shape analysis of each identical group of particles provides fundamental references of shape simulation strategy. Finally, computer simulation structures of blended cement paste both in fresh and hardened states will be compared with the experimental approach. Correlation of particle packing characteristics and properties of blended cement paste will be analyzed and discussed. Optimization of blending efficiency and improvement of concrete properties are pursued using packing modeling. [less ▲]

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See detailUtilisation du GPR pour la détection des discontinuités dans les tabliers de ponts
Van der Wielen, Audrey ULg; Nguyen, Frédéric ULg; Courard, Luc ULg

Scientific conference (2010, August 27)

Le Ground Penetrating Radar (GPR) est une technique non destructive utilisée depuis des décennies dans l’auscultation des sols. Depuis quelques années, l’apparition sur le marché d’antennes à hautes ... [more ▼]

Le Ground Penetrating Radar (GPR) est une technique non destructive utilisée depuis des décennies dans l’auscultation des sols. Depuis quelques années, l’apparition sur le marché d’antennes à hautes fréquences a permis d’appliquer cette méthode à des structures de moindre épaisseur, et notamment aux tabliers de ponts en béton. A l’Université de Liège, des travaux sont menés afin d’améliorer la détection des discontinuités dans les tabliers de ponts en béton. Dans une première étude expérimentale, 12 échantillons en béton contenant des défauts simulant des délaminations ont été réalisés et scannés par radar. Nous avons ainsi pu représenter les défauts en 3D et constater que leur visibilité était dépendante de leur épaisseur. Actuellement, une seconde étude théorique et expérimentale porte sur la détermination exacte de la limite de détection des couches minces. [less ▲]

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See detailTransport properties of mortars and concretes modified with medium hydraulic activity ground granulated blast furnace slags.
Hadj Sadok, Ahmed; Kenaï, Saïd; Courard, Luc ULg et al

in Sustainable Construction Materials and Technologies (2010, June)

Mechanical characteristics and durability of ground granulated blast furnace slag cement composites depends on the hydraulic activity of the slag. Algerian Blast furnace slag is characterized by a quite ... [more ▼]

Mechanical characteristics and durability of ground granulated blast furnace slag cement composites depends on the hydraulic activity of the slag. Algerian Blast furnace slag is characterized by a quite slow reactivity. Porosity and transport properties of mixes containing up to 50% OPC replacement are compared and analyzed. Mechanical strength, pore size distribution and capillary water absorption are studied after 28 and 90 days of wet curing. The durability of blast furnace slag cement concrete is evaluated through nitrogen permeability and water penetration depth under pressure. First observations seem to indicate finer porosity and lower water absorption than with 100% CEM I 52.5 mortars. Moreover, lower permeabilities to nitrogen and water are also observed for 50% blast furnace slag substitution. [less ▲]

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See detailFrom defects to causes: pathology of concrete and investigation methods.
Courard, Luc ULg; Van der Wielen, Audrey ULg; Darimont, Anne ULg

in Startegjia Izvedbe Sanacij Objektov (2010, May 19)

The proper planning of investigations before carrying out repair works is important if optimum use is to be made of the test data. A major step needs to be taken from knowing, for example, that chloride ... [more ▼]

The proper planning of investigations before carrying out repair works is important if optimum use is to be made of the test data. A major step needs to be taken from knowing, for example, that chloride is present in the concrete, to select the best methods for repair. Engineers require guidance on both the techniques available for the condition assessment of structures and the methods for data interpretation. Two major stages are usually recommended for such an operation: the first stage is based on a rapid-scan visual assessment, often including limited sampling in areas obviously damaged, from which areas can be selected for more detailed investigations. The second stage contains a detailed diagnostic survey that relies on destructive and non destructive testing techniques. Non destructive techniques are more and more utilized not only for the evaluation of the concrete strength but also for the detection of cracks and delaminations. Moreover, the interest for techniques able to evaluate concrete permeability is rising, due to the importance of this factor for durability evaluation. The paper will discuss the assessment of concrete structures and describe the main destructive and non destructive techniques with regard to specific pathologies. [less ▲]

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See detailRelation between bond quality and impact-echo frequency spectrum
Piotrowski, Tomasz; Garbacz, Andrzej; Van der Wielen, Audrey ULg et al

in Restoration of Buildings and Monuments = Bauinstandsetzen und Baudenkmalpflege (2010), 16(4/5), 303-314

According to EN 1504-10 and ACI Concrete Repair Manual, bond strength and interface quality are the main features of repair system necessary to be assessed. Pull-off test is most commonly used for bond ... [more ▼]

According to EN 1504-10 and ACI Concrete Repair Manual, bond strength and interface quality are the main features of repair system necessary to be assessed. Pull-off test is most commonly used for bond strength evaluation but growing interest in nondestructive techniques (NDT) is recently noted. Impact-echo (IE) is treated as the most promising one for this purpose. The aim of this paper is to analyze an effect of bond quality on stress wave propagation in repair systems. A group of samples has been prepared in order to obtain repair systems of different bond quality. Prior to repair, quality of concrete substrates has been characterized according different techniques: compressive strength, superficial cohesion, surface roughness index and cracking quantification. Than a polymer-modified repair mortar has been applied. After hardening, IE signals have been recorded and pull-off bond strength determined. The relationships between parameters characterizing surface quality, bond strength, IE frequency spectrum and results of wavelet analysis of IE signal have been analyzed. [less ▲]

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See detailOn the relation between bond quality and impact-echo frequency spectrum
Piotrowski, Tomasz; Garbacz, Andrzej; Van der Wielen, Audrey ULg et al

in Proceedings of the 13th International Congress on Polymers in Concrete ICPIC 2010 (2010)

According to EN 1504-10 and ACI Concrete Repair Manual, bond strength and interface quality are the main features of repair system necessary to be assessed. Pull-off test is most commonly used for bond ... [more ▼]

According to EN 1504-10 and ACI Concrete Repair Manual, bond strength and interface quality are the main features of repair system necessary to be assessed. Pull-off test is most commonly used for bond strength evaluation but growing interest in nondestructive techniques (NDT) is recently noted. Impact-echo (IE) is treated as the most promising one for this purpose. The aim of this paper is to analyze an effect of bond quality on stress wave propagation in repair systems. A group of samples has been prepared in order to obtain repair systems of different bond quality. Prior to repair, quality of concrete substrates has been characterized according different techniques: compressive strength, superficial cohesion, surface roughness index and cracking quantification. Than a polymer-modified repair mortar has been applied. Af-ter hardening, IE signals have been recorded and pull-off bond strength determined. The rela-tionships between parameters characterizing surface quality, bond strength, IE frequency spec-trum and results of wavelet analysis of IE signal have been analyzed. [less ▲]

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See detailWykorzystanie impact-echo i radaru do wykrywania defektow ukladu naprawczego nie zawierajacych warstwy powietrza
Garbacz, Andrzej; Harassek, Piotr; Van der Wielen, Audrey ULg et al

in 39th Polish Conference on Non destructive Testing Methods, Szczyrk 26-28 October, Zeszyty Problemowe. Badania nieniszczące (2010)

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See detailSurfology: what does it mean for polymer concrete composites?
Courard, Luc ULg; Garbacz, Andrzej

in Restoration of Buildings and Monuments = Bauinstandsetzen und Baudenkmalpflege (2010), 16(4/5), 1-12

Surfology is a scientific concept including all surface properties of materials and its influence on adhesion. The study of adhesion of polymer concrete composites is on the border - interface - between ... [more ▼]

Surfology is a scientific concept including all surface properties of materials and its influence on adhesion. The study of adhesion of polymer concrete composites is on the border - interface - between materials science and engineering. Interface quality is clearly influenced by surface properties of materials. Quality is uneasy to define but, at the level of interface, it could integrate all what favours the contact between concrete and polymers, like shrinkage, rigidity, surface roughness, wettability, viscosity…etc. 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. The objective of the paper is to analyse the effect of surface parameters (surfology) on polymer concrete composites. Influence of water content, roughness and type of material will be taken into account as factor influencing wettability and thermodynamic properties of surface. Viscosity and shear level of resinous materials will be considered in the same way. Engineering point of view will be taken into account through adhesion evaluation and correlated to surface material properties. [less ▲]

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See detailNondestructive Detection of Delaminations in Concrete Bridge Decks: A First Experimental Study
Van der Wielen, Audrey ULg; Courard, Luc ULg; Nguyen, Frédéric ULg

in Proceedings of the XIII International Conference on Ground Penetrating Radar (2010)

To detect delaminations in concrete bridge decks, nondestructive techniques (NDT) permit a frequent and large inspection of the slabs without damaging structures. This research was devoted to detect ... [more ▼]

To detect delaminations in concrete bridge decks, nondestructive techniques (NDT) permit a frequent and large inspection of the slabs without damaging structures. This research was devoted to detect simulated defects in twelve repaired concrete slabs. These were scanned with high frequency ground penetrating radar (GPR) with the common offset (CO) and common midpoint (CMP) methods. The electromagnetic waves speed was determined from CMPs. A 3D visualization program was also created to display the CO measurements. The visibility of the inserted defects revealed to be dependent on their lateral extension, their thickness and their constitutive material. [less ▲]

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See detailEvaluation of the effect of load eccentricity in a tensile pull-off test on bond strength
Courard, Luc ULg; Garbacz, Andrezj

Report (2010)

The report presents the results of a research project and the impact of incorrect design on tensile strength values. According to results of laboratory experiments and modelling, it can be observed that ... [more ▼]

The report presents the results of a research project and the impact of incorrect design on tensile strength values. According to results of laboratory experiments and modelling, it can be observed that, if there is an influence of 2° and 4° angle of inclination on pull-off bond strength, it is however not statistically significant: the decrease of pull-off strength is usually no larger than 14% for 4°. [less ▲]

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See detailAppétence et adhérence des systèmes de réparation : importance de la préparation du support
Courard, Luc ULg

Conference (2010)

La compatibilité – ou appétence - entre un système de réparation et le béton support est définie à partir des propriétés du support et de la couche d’apport – essentiellement dans sa phase non liée – ... [more ▼]

La compatibilité – ou appétence - entre un système de réparation et le béton support est définie à partir des propriétés du support et de la couche d’apport – essentiellement dans sa phase non liée – ainsi que de l’environnement dans lequel le contact est créé. Elle s’exprime habituellement en termes de variations dimensionnelles, de perméabilité et de propriétés chimiques et électrochimiques. Ces propriétés sont évoquées ou développées pour chacun des matériaux mis en présence : rugosité, porosité, cohésion superficielle et eau interstitielle pour le béton ; retrait, fluage, rigidité, absorption capillaire pour les produits de réparation. Trois conditions fondamentales nécessaires et suffisantes au développement de l’adhérence en tant que signe de la compatibilité entre matériaux sont évoquées et illustrées pour le cas particulier de la préparation de surface : sablage, burinage, hydro démolition, marteau-piqueur, … ont un effet spécifique non seulement sur la rugosité, et donc l’accrochage mécanique du système de réparation, mais aussi sur la cohésion de la couche superficielle du béton [less ▲]

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See detailRepairing Concrete Industrial Floors with Bonded Cement-based Material Overlays: some recommendations
Courard, Luc ULg; Bissonnette, Benoît; Vaysburd, Alex

in Littmann, Klaus (Ed.) Industrial Floors 2010 (2010)

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 detailEglise Saint-Voncent: compte-rendu de l'inspection visuelle et des essais réalisés
Gillard, Anne ULg; Courard, Luc ULg; Darimont, Anne ULg

Report (2010)

Dans le cadre du mémoire de fin d'études sur l'église Saint-Vincent, des recherches documentaires ont été effectuées afin de comprendre les volontés de l'architecte, le système structurel en place, ou ... [more ▼]

Dans le cadre du mémoire de fin d'études sur l'église Saint-Vincent, des recherches documentaires ont été effectuées afin de comprendre les volontés de l'architecte, le système structurel en place, ou encore les modifications apportées depuis la construction. Il est effectivement important d'approcher le bâtiment, avant de chercher ses éventuels défauts ou dégâts. Une inspection visuelle, nécessitant plusieurs visites du bâtiment, a permis de lister les dégradations, à l'aide d'un mètre et d'un appareil photo. Celles-ci concernent des problèmes liés au béton (fissures, épaufrures, traces de corrosion, … ), des problèmes structurels (fissures dans les éléments structurels et en façade) ou des problèmes de types divers (humidité, … ). Pour chacune des dégradations observées, les origines possibles ont été formulées. Ensuite, des sesais ou des examens visuels approfondis, nécessaires à l'identification de l'origine exacte des dégâts, ont été proposés. L'utilisation du radar a permis de préciser l'origine de certaines dégradations décrites dans le mémoire. Elle a également été utile pour rechercher la composition des parois, en comparant les radargrammes aux informations fournies par les prélèvements effectués en façade. Les premiers échantillons, prélevés au niveau du rez-de-chaussée, ont fait l'objet d'essais visant à caractériser les matériaux présents : test à la phénolphtaléine, mesure de l'absorption d'eau, mesure de la résistance en compression et en traction. Des analyses physiques et chimiques, suivies d'observations au microscope d'échantillons rélevés en façade ouest, ont par ailleurs permis de caractériser la Pierre armée Pauchot. [less ▲]

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See detailSurfology: what does it mean for polymer concrete composites?
Courard, Luc ULg; Garbacz, Andrzej

in Proceedings of the 13th International Congress on Polymers in Concrete ICPIC 2010 (2010)

Surfology is a scientific concept including all surface properties of materials and its influence on adhesion. The study of adhesion of polymer concrete composites is on the border - interface - between ... [more ▼]

Surfology is a scientific concept including all surface properties of materials and its influence on adhesion. The study of adhesion of polymer concrete composites is on the border - interface - between materials science and engineering. Interface quality is clearly influenced by surface properties of materials. Quality is uneasy to define but, at the level of interface, it could integrate all what favours the contact between concrete and polymers, like shrinkage, rigidity, surface roughness, wettability, viscosity…etc. 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. The objective of the paper is to analyse the effect of surface parameters (surfology) on poly-mer concrete composites. Influence of water content, roughness and type of material will be taken into account as factor influencing wettability and thermodynamic properties of surface. Viscosity and shear level of resinous materials will be considered in the same way. Engineering point of view will be taken into account through adhesion evaluation and correlated to surface material properties. [less ▲]

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See detailEvaluatie van de gevolgen van de aanwezigheid van kalknodules in beton - Besluiten
Courard, Luc ULg; Darimont, Anne ULg; Degée, Hervé ULg

Report (2010)

De oorspronkelijke verontreiniging (0.7% van het gewicht aan granulaten) is met factor 100 verminderd tijdens de productie van de granulaten en het verwerken van het beton. De maximale verontreiniging ... [more ▼]

De oorspronkelijke verontreiniging (0.7% van het gewicht aan granulaten) is met factor 100 verminderd tijdens de productie van de granulaten en het verwerken van het beton. De maximale verontreiniging geobserveerd op de werf is 0.006% van het gewicht aan granulaten. Op de werf zijn de pop-outs weinig talrijk, de kalknodules zijn klein en de pop-outs ondiep. Geen enkele scheurvorming trof het beton. Het besluit van deze studie, op basis van een worstcasescenario en met een aan zekerheid grenzende waarschijnlijkheid, is dat de verontreiniging geen risico inhoudt wat betreft duurzaamheid en stabiliteit van de werken. We bedoelen daarmee dat het risico op verlies van sterkte en het risico voor stabiliteit en duurzaamheid van structurele elementen (platen, wanden, balken) verbonden aan de aanwezigheid van nodules zo miniem zijn dat ze in feite kleiner zijn dan de risico’s ten gevolge van de normaal aanvaardbare variabiliteit van de eigenschappen van beton, in overeenstemming met de omstandigheden op de werf. Na hydratatie oefenen de verdichte portlandiet-nodules geen druk meer uit en gedragen ze zich als gewone granulaten. De risico’s verbonden aan de betonverontreiniging door kalknodules zijn dus uitsluitend esthetisch van aard en betreffen een maximale diepte van 2 tot 4 cm. [less ▲]

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