References of "Michel, Frédéric"
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See detailLimestone fillers cement-based composites: effects of blast furnace slags on fresh and hardened properties
Courard, Luc ULg; Michel, Frédéric ULg

in Construction and Building Materials (2014), 51

Limestone filler is a raw material that is already used in several applications like paints, bricks, bituminous mixtures…etc. Moreover, and particularly in Belgium, classical additions for concrete like ... [more ▼]

Limestone filler is a raw material that is already used in several applications like paints, bricks, bituminous mixtures…etc. Moreover, and particularly in Belgium, classical additions for concrete like fly ashes and granulated blast furnace slags are becoming rare; there is a need for new additions that could have a positive effect on the properties of the fresh and hardened cementitous composites. Substitution of limestone filler in Portland cement and Granulated blast furnace slag cement has been realized between 15 and 27 % in mass. In addition to the characterization of the powder itself – specific mass, specific surface and laser granulometry – the problem of the water demand has been analysed: it seems that it remains constant with the substitution rate. Electric conductivity has also been performed in order to study the evolution of the “dormant” period. Tests on hardened mortars were performed with regard to mechanical properties and evolution of the porosity. Test results indicate that the porosity seems to be finer in the case of granulated blast furnace slags cements, partially due to a very low diameter of the slags particles. Oxygen permeability doesn’t seem to be influenced by the filler while capillary absorption increases with substitution rate. Finally, carbonation rate, sulphate resistance and chloride penetration show quite interesting behaviours, leading to the conclusion that limestone fillers maybe a good substitution material. [less ▲]

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See detailEffects of limestone fillers on surface free energy and electrical conductivity of the interstitial solution of cement mixes
Courard, Luc ULg; Michel, Frédéric ULg; Perkowicz, Sylwia et al

in Cement and Concrete Composites (2014), 45

Most of concrete formulations actually contain mineral additives that are used as an inert filler or supplementary cementitious material (as type II addition). These materials are generally used in order ... [more ▼]

Most of concrete formulations actually contain mineral additives that are used as an inert filler or supplementary cementitious material (as type II addition). These materials are generally used in order to increase concrete performances both in its fresh and hardened states. The mineral additives usually improve the consistency and workability of fresh concrete and reduce the water demand for a required concrete slump because of an additional volume of fines. The way of action depends on the physical and chemical characteristics of fillers. The study of surface free energies and electric conductivities of interstitial solutions of cement mixes modified by blast furnace slags and limestone fillers contributes to a better knowledge of hardening and interaction process. [less ▲]

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See detailDurability of hydrophobic treatments on concrete monuments
Courard, Luc ULg; Lucquiaud, Vincent ULg; Gérard, Olivier et al

in Proceedings of 7th International Conference on Water Repellent Treatment and Protective Surface Technology for Building Materials (2014)

The protection of concrete historical structures is a challenge for the coming years. Hydrophobic treatment may induce a delay in degradations progress as well as a protection against water penetration ... [more ▼]

The protection of concrete historical structures is a challenge for the coming years. Hydrophobic treatment may induce a delay in degradations progress as well as a protection against water penetration. Existing products - mainly silane and siloxane based – have been submitted to different ageing processes including UV radiation, moistening cycles, thermal shocks, freeze-thaw cycles, carbonation and efficiency has been evaluated on the base of contact angle, vapour and chloride permeability and, capillarity absorption. Investigation results clearly show a good behaviour of hydrophobic treatments under main ageing conditions. [less ▲]

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See detailParticle size distribution of limestone fillers: granulometry and specific surface area investigations
Courard, Luc ULg; Michel, Frédéric ULg

in Particulate Science and Technology (2014), 32(4),

Mineral fillers can be defined as “inert materials included in a mix design for some useful purpose”. They can be added to compounds in order to complete a large variety of final properties without ... [more ▼]

Mineral fillers can be defined as “inert materials included in a mix design for some useful purpose”. They can be added to compounds in order to complete a large variety of final properties without increasing costs or to improve specific characteristics like hardness, brittleness, impact strength, compressive strength, softening point, fire resistance, surface texture, electrical conductivity, …etc. In Belgium, locally available limestone fillers are specifically very well-adapted for the optimisation of particle packing and flow behaviour of cementitious pastes in concrete mixes. Limestone fillers may be easily characterized in terms of chemical and mineralogical properties. These properties are fundamental for the study of the behaviour of concrete mixes in fresh state and for understanding interactions existing at the level of the Interfacial Transition Zone between aggregates and cement paste. These properties are however insufficiently discriminant and particle size, as well as shape distribution, seem to have a potential influence on physical phenomena which happen during the setting process. The aim of this paper is to compare five major techniques used to quantify the size and the shape of limestone fillers particles: laser diffraction scattering, wet sieving and image analysis for particle size measurement and BET adsorption and Blaine permeability methods for specific surface area. [less ▲]

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See detailInfluence of particle shape on size distribution measurements by 3D and 2D image analyses and laser diffraction
Califice, Arnaud ULg; Michel, Frédéric ULg; Dislaire, Godefroid ULg et al

in Powder Technology (2013), 237

This paper highlights the fact that particle size distribution (PSD) is not unique for the same product, and is dependent on the chosen measurement technique, especially for asymmetric shapes. Laser ... [more ▼]

This paper highlights the fact that particle size distribution (PSD) is not unique for the same product, and is dependent on the chosen measurement technique, especially for asymmetric shapes. Laser diffraction and 2D image analysis are commonly used PSD measurement techniques. However, the resultsmay not be representative of the true physical dimensions of the particles. The influence of particle shape on PSD results obtained from 2D/3D image analysis and laser diffraction was investigated. Two metallic powders presenting extreme shape properties (round and elongated particles) were analyzed, as well as a blend of the two pure products. 2D image analysis and laser diffraction results were compared to 3D image analysis (measuring the true particle size). This paper compares the PSD results obtained from the three methods. Some commonly used size parameters in image analysis software did not give meaningful results in regard of the true physical dimensions of the particles. The existence of the two populations (products with extremely different shape and size characteristics) could not be identified with such size parameters, and laser diffraction also performed poorly. The PSD obtained from more precise size parameters (image analysis) better corresponded to the true dimensions of the particles. This study highlights the strengths and weaknesses of particle size analysis techniques when studying products presenting diverse particle shapes, and points out that caution is required in the choice of the size parameters, and in the interpretation of PSD results. [less ▲]

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See detailDetermination of Moisture Diffusivity During Drying of Mortar Cement: Experimental and Modeling Study
Bennamoun, Lyes ULg; Kahlerras, Loubna ULg; Michel, Frédéric ULg et al

in International Journal of Energy Engineering (2013), 3(1), 1-6

The aim of this study is the experimental characterization of the behaviour of a mortar during convective drying. We focalise on mortar that has a rate water-cement of 0.5. The drying tests are developed ... [more ▼]

The aim of this study is the experimental characterization of the behaviour of a mortar during convective drying. We focalise on mortar that has a rate water-cement of 0.5. The drying tests are developed in a micro-convective dryer that can use samples weighing from 0 to 8g. The advantage of these experiments is to reproduce the natural conditions that can be found during the treatment of the mortar-atmosphere problems. The response of the drying curve or the drying kinetic depends on the applied drying conditions. So, the temperature of the air varies from 60°C to 130°C, the velocity of the air is changed from 2 m.s-1 to 5 m. s-1and the relative humidity is kept less than 1.7%. The comparison between the experimental results and the proposed analytical solutions of the equation of diffusion represented by Fick’s law, applied for a finite shape, allows determination of the values of the diffusion coefficient. It has a value of 1.71×10-10 m2.s-1 at 60°C, 13.69×10-10 m2.s-1 at 90°C and 16.27×10-10 m2.s-1 at 130°C. Calculation of the activation energy and the D0 constant are also possible. [less ▲]

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See detailFixation du CO2 dans les blocs de béton à base de granulats recyclés
Parmentier, Véronique; Michel, Frédéric ULg; Courard, Luc ULg

in Gagné, Richard (Ed.) Actes de la 14ème édition des Journées Scientifiques (2013)

A l’heure où l’industrie cimentière est majoritairement responsable de la production de CO2 dans le secteur de la construction, il s’avère utile de compenser cette production par un phénomène inverse: la ... [more ▼]

A l’heure où l’industrie cimentière est majoritairement responsable de la production de CO2 dans le secteur de la construction, il s’avère utile de compenser cette production par un phénomène inverse: la captation du CO2. Ce processus d’absorption de CO2, appelé carbonatation, améliore certaines propriétés du béton lors de la conversion du dioxyde de carbone CO2 en carbonate de calcium CaCO3. Les préoccupations environnementales actuelles motivent l’étude de la carbonatation dans le but de maximiser l'absorption du dioxyde de carbone. Les granulats recyclés, produits à base de déchets de béton concassés mécaniquement, peuvent prendre place dans de nouvelles applications en béton. Ils peuvent remplacer les granulats naturels en tout ou en partie, épargnant ainsi l’extraction des matières premières naturelles. La combinaison des deux approches vise à élaborer un produit dont l’impact environnemental est réduit au minimum. [less ▲]

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See detailUse of contaminated recycled aggregates for concrete design: properties and durability
Courard, Luc ULg; Michel, Frédéric ULg; Debieb, Farid

in Zajc, Andrej (Ed.) Doseganje posebnih lastnosti betonov z uporabo odpadlih materialov (2012, May 23)

Construction waste management is a quite important economic and environmental deal for our societies. More than 2 million tons demolition and construction wastes are annually produced only in Wallonia ... [more ▼]

Construction waste management is a quite important economic and environmental deal for our societies. More than 2 million tons demolition and construction wastes are annually produced only in Wallonia, Southern Region of Belgium; recycling has clearly to be promoted. Roller Compacted Concrete (RCC) is a special dry concrete made of aggregates, water and low quantity of cement, laid down and compacted like a soil, for the construction of massive structures like dams or large horizontal surfaces like road foundations. Replacement of natural aggregates by concrete road recycled aggregates in the mix design of concrete is a solution to decrease nature depletion. Natural concrete slabs were cured in water, sea water, chloride solutions or sulphate solutions and then crushed to obtain virgin and contaminated (polluted) recycled aggregates. The aim of this research is the total replacement (100% coarse and fine) of natural aggregates (NA) by recycled concrete aggregates (RA) in the composition of a roller compacted concrete. The natural and recycled aggregates are characterised and compared. The mechanical properties and durability performances of concrete with contaminated RA are analysed. The experimental results showed that the polluted RA are much richer in chlorides than in sulphates and are leached if they are soaked in water. Significant differences were observed between the properties of original and new concrete and the results demonstrated the need of taking these contaminations into account. [less ▲]

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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 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 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 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 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 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 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 detailInfluence of clay in limestone fillers for self compacting cement based composites
Courard, Luc ULg; Michel, Frédéric ULg; Piérard, Julie

in Construction & Building Materials (2011), 25

High workability together with a good resistance to segregation is needed for cement based composites, specifically fresh Self-Compacting Mortars (SCM); in this prospect, the amount of coarse materials ... [more ▼]

High workability together with a good resistance to segregation is needed for cement based composites, specifically fresh Self-Compacting Mortars (SCM); in this prospect, the amount of coarse materials has to be reduced and replaced by fine material. Several limestone fillers are here compared and analysed. These by-products are issued from different industrial sectors, such as the aggregate and lime production industry (quarrying operations) and the ornamental stones industry (sawing operations). Particular attention has been paid to clay content, as consistency of fresh mortars was varying, while other physical characteristics like granulometry remained the same. Relationship between the physico-chemical properties of the fillers and the properties of fresh and hardened mortars are brought forward. Even if it may affect fresh properties of mortars, results clearly show that clay type and content has minor influence than limestone filler itself. [less ▲]

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See detailThe evaluation of the surface free energy of liquids and solids in concrete technology
Courard, Luc ULg; Michel, Frédéric ULg; Martin, Marie

in Construction & Building Materials (2011), 25

This paper presents initial results from an extensive study on the calculation of the surface free energy of mineral materials. The usefulness of such evaluation is demonstrated through the technological ... [more ▼]

This paper presents initial results from an extensive study on the calculation of the surface free energy of mineral materials. The usefulness of such evaluation is demonstrated through the technological operation of casting and moulding concrete. Surface interactions will firstly act on the dispersion of particles inside the concrete mix and the viscosity of the fresh material; the specific effect of superplasticizers and Modifying Viscosity Agent is presented through the determination of surface free energy properties. The second analysis is dealing with the interactions between mineral and vegetal oils applied on the wooden or steel formwork and fresh concrete. The evaluation of contact angle and interfacial forces help to efficiently select the most appropriate material. [less ▲]

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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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