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See detailChangements dans l’art de construire: le choix des matériaux
Courard, Luc ULg

Conference (2012, April 25)

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See detailStatic Detection of Thin Layers into Concrete with Ground Penetrating Radar
Van der Wielen, Audrey ULg; Courard, Luc ULg; Nguyen, Frédéric ULg

in Restoration of Buildings and Monuments = Bauinstandsetzen und Baudenkmalpflege (2012), 18(3/4), 247-254

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 concrete bridge deck 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, most commercial GPR systems emit a large frequency band wavelet, which undergoes attenuation into the layer. To analyze 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 detailEffet de l'empilement et de la forme des additions dans les propriétés des liants à matrice cimentaire
He, Huan; Courard, Luc ULg; Michel, Frédéric et al

in Georgin, Jean-François (Ed.) Compte-rendu des Journées Scientifiques du (RF)2B (2012)

Cement blending with mineral admixtures, especially with by-product or waste product powder, can effectively reduce consumption of cement and promote the ecology. Recently, an innovative concept was ... [more ▼]

Cement blending with mineral admixtures, especially with by-product or waste product powder, can effectively reduce consumption of cement and promote the ecology. Recently, an innovative concept was proposed to replace of “coarse” cement grains by the inert fillers for sustainable cement in the low w/c concrete cement. As a basic mechanism, particle packing plays an important role in such replacement or blending. In the first part of study, the paper discusses the particle packing aspect of cement grains, limestone filler (LF) and LF blended cement. The new developed wet packing method and a dry packing method are proposed for the evaluation purpose. Particle size distributions (PSDs) and particle shape of different powders are firstly characterized by an advanced image analysis system. The paper presents results of packing tests with the influences of PSD, particle shape, cement type, vibration, mixing, superplasticizer (SP), blending proportions, etc. The advantages and limitations of two packing methods are also discussed in this paper. [less ▲]

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See detailShape simulation of granular particles in concrete and applications in DEM
Huan, He; Stroeven, Piet; Pirard, Eric ULg et al

in Brandt, A.M.; Olek, J.; Glinicki, L.A. (Eds.) et al Proceedings of the International Symposium Brittle Matrix Composites 10 (2012)

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See detailSupplementary Cementitious Materials for Concrete: Characterization Needs
Juenger, Maria; Provis, John L.; Elsen, Jan et al

in Proceedings of the XXI International Materials Research (2012)

A wide variety of materials are currently used as supplementary cementitious materials (SCMs) for concrete, including natural materials and byproducts from various industries. Historically, natural SCMs ... [more ▼]

A wide variety of materials are currently used as supplementary cementitious materials (SCMs) for concrete, including natural materials and byproducts from various industries. Historically, natural SCMs, mostly derived from volcanic deposits, were common in concrete. In recent years, the dominant SCMs have been industrial by-products such as fly ash, ground granulated blast furnace slag (GGBFS), and silica fume. There is currently a resurgence of research into historic and natural SCMs, as well as other alternative SCMs for many reasons. The primary benefits of SCM use in improvement of long-term mechanical performance, durability, and sustainability are widely accepted, so local demand for these materials can exceed supply. This paper describes some of the SCMs that are attracting attention in the global research community and the properties and characteristics of these materials that affect their performance. Special attention is paid to the importance and demands of material characterization. Many SCMs do not necessarily lend themselves to characterization methods used in standardized test methods, which sometimes fail to describe the properties that are most important in predicting reactivity. [less ▲]

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See detailFly ash polymer concrete quality assessment using ultrasonic method
Garbacz, Andzej; Sokolowska, Johanna; Lutomirski, Arkadiusz et al

in Ozkul, M.H. (Ed.) Proceedings of the 7th Asian Symposium of Polymers in Concrete (2012)

Polymer concretes appear as useful materials for manufacturing precast elements as well as for repair and protection of building structures. In both cases, there is a need for quality control and ... [more ▼]

Polymer concretes appear as useful materials for manufacturing precast elements as well as for repair and protection of building structures. In both cases, there is a need for quality control and diagnosis during service life as well. Therefore the development of nondestructive assessment methods is an important issue. Ultrasonic methods are among the most common nondestructive techniques used in material science and industry. The aim of the paper was to analyze the usability of ultrasonic methods for assessing properties of polymer concretes modified with fly ashes. In the paper the effects of substitution of microfiller with fly ash in polyester and vinyl ester concretes on ultrasonic wave propagation are presented. Compositions of tested fly ash polymer concretes were determined using material optimization approach. Propagation of ultrasonic wave was characterized using wave velocity and a frequency spectrum characteristic. As a result, regression functions for ultrasonic evaluation of fly ash polymer concrete are proposed. Those functions can be used to develop reference curves for calibration procedures for this kind of composites. [less ▲]

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See detailTopography evaluation methods for concrete substrates: parametric study
Courard, Luc ULg; Garbacz, Andrzej; Bissonnette, Benoît

in Alexander, Mark (Ed.) Concrete Repair, Rehabilitation and Retrofitting III (2012)

Research projects performed at the University of Liege, Laval University and the Warsaw University of Technology have pointed out the importance of taking care about the surface roughness of concrete ... [more ▼]

Research projects performed at the University of Liege, Laval University and the Warsaw University of Technology have pointed out the importance of taking care about the surface roughness of concrete substrate with regards to the adhesion of repair materials. This paper wants to make a State-of-Art on this specific problem: surfometry methods, interface analysis, adhesion measurements, …etc are presented, interpreted and compared. Surfology, which is a more wide concept, 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 detailInfluence of the reuse of OSB and marine plywood formworks on concrete surface aesthetics
Courard, Luc ULg; Martin, Marie; Goffinet, Cécile et al

in Materials and Structures (2012), 45(9), 1331-1343

Concrete surface quality becomes more and more important because aesthetics requirements tend to spread over a wide variety of construction works. Even if it is difficult to clearly define what is ... [more ▼]

Concrete surface quality becomes more and more important because aesthetics requirements tend to spread over a wide variety of construction works. Even if it is difficult to clearly define what is beautiful or not, existing techniques maybe used to quantify aesthetic properties of concrete. As they mainly depend on formwork, the research project focuses on the reuse of two types of panels – plywood and OSB – and two types of release agents – vegetal and mineral oils. Evolution of surface properties is measured through lightness and absorption. For plywood formworks, beyond 80 reuses, a modification of surface quality is noticed; this is only 50 for OSB panels. For both types of formworks, the release oil doesn’t seem to have a major influence on formwork absorption. It is also observed that alkalis cause early degradation of the panels: release agents are not always efficient to avoid this phenomenon. Finally, if reuse doesn’t have any influence on the absorption of the plywood formworks, it is not the case for OSB formworks. [less ▲]

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See detailComparison of Destructive Methods to Appraise the Mechanical Integrity of a Concrete Surface
Courard, Luc ULg; Bissonnette, Benoît; Vaysburd, Alex et al

in Concrete Repair Bulletin (2012), 25(4), 22-30

Depending on the technique being used, the concrete removal operation prior to repair can be harmful to the residual concrete skin left on the structure. Whenever a tight bond between the repair and the ... [more ▼]

Depending on the technique being used, the concrete removal operation prior to repair can be harmful to the residual concrete skin left on the structure. Whenever a tight bond between the repair and the old concrete is required, the soundness of the prepared surface should thus be assessed. Although this is widely recognized, there is no standard method intended to characterize the integrity of a concrete substrate after concrete removal. This paper presents the results of an investigation intended to assess and compare quantitatively different test methods, namely the Schmidt rebound hammer, the pull-out test and the pull-off test, to evaluate superficial mechanical integrity of a substrate after concrete removal operations. Although it does not yield a precise evaluation of compressive strength, the Schmidt rebound hammer test is recognized as a useful tool for performing quick surveys to assess concrete uniformity. The pull-off test is very well correlated with the splitting-tensile test, but it is not suited for vertical and overhead surfaces. The Capo pull-out test has limited interest for surface preparation, as it is applicable to flat surfaces only. Conversely, the accelerated pull-out test showed interesting potential as a simple and relatively rapid means for assessing the mechanical integrity of a concrete surface prior to repair for any type of concrete surface. More work is definitely required to refine the procedures and develop performance criteria. Nevertheless, it appears from the results generated in this study that the combination Schmidt hammer / pull-off test could fill the needs for the evaluation of horizontal surfaces after concrete removal, while the combination Schmidt hammer / accelerated pull-out test could be used effectively on vertical and overhead surfaces. [less ▲]

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See detailEffet de l’empilement et de la forme des additions sur les propriétés des liants à matrice cimentaire
He, Huan; Courard, Luc ULg; Michel, Frédéric ULg et al

in Georgin, Jean-François (Ed.) Recueil des communications des journées scientifiques du (RF)²B (2012)

Mélanger le ciment avec des additions minérales, en particulier avec des sous-produits industriels, permet de réduire efficacement la consommation de ciment et de réduire son impact environnemental ... [more ▼]

Mélanger le ciment avec des additions minérales, en particulier avec des sous-produits industriels, permet de réduire efficacement la consommation de ciment et de réduire son impact environnemental. Récemment, un concept novateur a été proposé en vue de remplacer les plus gros grains de ciment par les charges inertes, en vue du développement d’un ciment durable. En tant que mécanisme de base, l’empilement des particules joue un rôle important dans le remplacement ou le mélange. Dans la première partie de l'étude, l’empilement des grains de ciment, de filler calcaire (LF) et de ciment mélangé est abordé. Une nouvelle méthode, basée sur l’empilement en phase humide, est comparée à une méthode d'empilement à sec. La distribution de taille des particules (PSD) et la forme des particules des différentes poudres sont caractérisées sur base d’un système d'analyse d'image avancée. Le document présente les résultats des tests d’empilement avec l’influence du paramètre PSD, de la forme des particules, du type de ciment, de l’énergie de vibration, du mélange et du superplastifiant (Sp). Les avantages et les limites des deux méthodes sont également discutés. [less ▲]

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See detailParticle packing density and limestone fillers for more sustainable cement
He, Huan ULg; Courard, Luc ULg; Pirard, Eric ULg

in Key Engineering Materials [=KEM] (2012), 517

Cement blending with mineral admixtures, especially with byproduct or waste product powder, can effectively reduce consumption of cement and promote the ecology. Recently, an innovative concept was ... [more ▼]

Cement blending with mineral admixtures, especially with byproduct or waste product powder, can effectively reduce consumption of cement and promote the ecology. Recently, an innovative concept was proposed to replace of “coarse” cement grains by the inert fillers for sustainable cement in the low w/c concrete cement. As a basic mechanism, particle packing plays an important role in such replacement or blending. In the first part of study, the paper discusses the particle packing aspect of cement grains, limestone filler (LF) and LF blended cement. The new developed wet packing method and a dry packing method are proposed for the evaluation purpose. The paper presents results of packing tests with the influences of PSD, cement type, vibration, mixing, blending proportions, etc. The advantages and limitations of two packing methods are also discussed in this paper. [less ▲]

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See detailPathologies of concrete in Saint-Vincent Neo-Byzantine Church and Pauchot reinforced artificial stone
Courard, Luc ULg; Gillard, Anne; Darimont, Anne ULg et al

in Construction & Building Materials (2012), 34

Reinforced concrete is a key element of the architectural evolution and has been specifically involved in the development of Catholic Church architecture, particularly during the second part of the XXth ... [more ▼]

Reinforced concrete is a key element of the architectural evolution and has been specifically involved in the development of Catholic Church architecture, particularly during the second part of the XXth century. This article focuses on the Saint-Vincent Church, Liege district, Belgium. With concrete as major building material, this was built in only 20 months, from 1928 to 1930. This monumental building, from Neo Byzantine style, however presents some degradations. A visual inspection, as well as non destructive and laboratory tests, are presented and analysed. They help to make a clear diagnosis and to assess hypothesis on the real state of this high-quality architectural building. Moreover, specific investigations have been realized on a special mortar used for wall construction: Pauchot reinforced artificial stone. [less ▲]

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See detailDurability of mortar and concretes containing slag with low hydraulic activity
Hadj Sadok, Ahmed; Kenaï, Saïd; Courard, Luc ULg et al

in Cement & Concrete Composites (2012), 34(5), 671677

Granulated blast furnace slag has been widely used as a partial substitute for Portland cement in many applications because of advantages which include cost reduction, reduction in heat evolution and ... [more ▼]

Granulated blast furnace slag has been widely used as a partial substitute for Portland cement in many applications because of advantages which include cost reduction, reduction in heat evolution and improvement of durability properties. However, the effectiveness of slag depends on its hydraulic reactivity. In this paper, the results of an experimental study on the effect of slag with low hydraulicity on the mechanical and durability properties of concrete and the performance of mortar under sulfate attack are discussed. Special attention is given to gas permeability and water absorption of slag concrete. The durability of slag concrete is improved at long term at low Water/Binder ratio. Sulfate resistance of mortar is improved by slag replacement up to 30%. [less ▲]

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See detailNatural limestone fillers : physical and chemical properties with regard to cement based materials performances
Michel, Frédéric ULg; Courard, Luc ULg

in Durability of concrete 2012 (2012)

Natural limestone fillers are available on the market and supplied by limestone aggregates industry but also ornamental stone suppliers. The use of limestone fillers in cement based concrete requires a ... [more ▼]

Natural limestone fillers are available on the market and supplied by limestone aggregates industry but also ornamental stone suppliers. The use of limestone fillers in cement based concrete requires a thorough characterization of the materials. Physical and chemical properties will influence behaviour of the fresh and hardened concrete. Impurities may affect cement hydration process, delay the setting time and decrease the compressive strength. Six types of limestone fillers, in the form of finely ground limestone powders, have been collected in Belgium (more precisely in Wallonia Region). They differ from each other through their physical properties (Blaine fineness, particle size distribution, water demand) but also chemical and mineralogical properties (presence of impurities such as sulphate, clay, quartz and dolomite). Special attention has been focused on clay content and type influences; limestone fillers have been artificially polluted with clays in order to investigate their behaviour in cement based mortars. The effect of the nature and the substitution rate of the fillers on the properties of mortars are investigated. Relationships between physico-chemical properties of the fillers and the properties of mortars clearly indicate a harder influence of the limestone composition on the fresh than the hardened properties. [less ▲]

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See detailMatériaux de construction
Courard, Luc ULg

Learning material (2012)

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See detail300e conférence du C.E.R.E.S
Courard, Luc ULg; Dehousse, Nicolas ULg; Demonceau, Jean-François ULg et al

Book published by Centre d'Etudes, de Recherches et d'Essais Scientifiques du Génie Civil (2011)

Cette brochure comprend: le mot du président, un historique du CERES, la liste des bulletins, mémoires et conférences du CERES depuis ses origines jusqu'à ce jour, la liste des présidents, secrétaires et ... [more ▼]

Cette brochure comprend: le mot du président, un historique du CERES, la liste des bulletins, mémoires et conférences du CERES depuis ses origines jusqu'à ce jour, la liste des présidents, secrétaires et trésoriers, un mot de conclusions, ainsi que le programme de la manifestation organisée à l'occasion de la trois centième conférence du CERES. [less ▲]

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See detailCharacterization of fine aggregates in concrete by different experimental approaches
He, Huan ULg; Courard, Luc ULg; Pirard, Eric ULg et al

in Proceedings 13 Int. Congress for Stereology (2011, October)

Being its major component, aggregate can occupy up to three-quarter of the volume of concrete. The structure of aggregate formed in hardened state impacts largely on mechanical and durability properties ... [more ▼]

Being its major component, aggregate can occupy up to three-quarter of the volume of concrete. The structure of aggregate formed in hardened state impacts largely on mechanical and durability properties of concrete. On another hand, physical characteristics of aggregate are primarily assumed to be relevant to granular behavior of aggregate. Therefore, characterization of aggregate is of high relevance to concrete studies. In this study, different types of fine aggregate used in concrete, namely river sand and crushed limestone, are selected for morphological characterization. Traditional sieve analysis and laser diffraction method are employed for separation and size analysis of specimens. Different types of fine aggregate samples with comparable size ranges are then analyzed by two advanced dry (static) and wet (dynamic) image analysers. These new analysers are especially suitable for characterization of fine particles, which is difficult by traditional image analysis equipments. Size and shape characteristics of different fine aggregates will be revealed by different experimental methods. The results on different parameters for shape characterization will be compared and discussed. [less ▲]

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See detailCharacterization of fine aggregates in concrete by different experimental approaches
He, Huan; Courard, Luc ULg; Pirard, Eric ULg et al

in Proceedings 13 Int. Congress for Stereology (2011, October)

Being its major component, aggregate can occupy up to three-quarter of the volume of concrete. The structure of aggregate formed in hardened state impacts largely on mechanical and durability properties ... [more ▼]

Being its major component, aggregate can occupy up to three-quarter of the volume of concrete. The structure of aggregate formed in hardened state impacts largely on mechanical and durability properties of concrete. On another hand, physical characteristics of aggregate are primarily assumed to be relevant to granular behavior of aggregate. Therefore, characterization of aggregate is of high relevance to concrete studies. In this study, different types of fine aggregate used in concrete, namely river sand and crushed limestone, are selected for morphological characterization. Traditional sieve analysis and laser diffraction method are employed for separation and size analysis of specimens. Different types of fine aggregate samples with comparable size ranges are then analyzed by two advanced dry (static) and wet (dynamic) image analysers. These new analysers are especially suitable for characterization of fine particles, which is difficult by traditional image analysis equipments. Size and shape characteristics of different fine aggregates will be revealed by different experimental methods. The results on different parameters for shape characterization will be compared and discussed [less ▲]

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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 ▲]

Detailed reference viewed: 104 (17 ULg)