References of "Darimont, Anne"
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See detailEffects of the presence of free lime nodules into concrete: experimentation and modelling
Courard, Luc ULg; Degée, Hervé ULg; Darimont, Anne ULg

in Cement and Concrete Research (2014), 64

When nodules of lime are embedded into concrete, the expansion accompanying the transformation of CaO into Ca(OH)2 induces stresses and strains in both the lime nodule and in the concrete matrix. The ... [more ▼]

When nodules of lime are embedded into concrete, the expansion accompanying the transformation of CaO into Ca(OH)2 induces stresses and strains in both the lime nodule and in the concrete matrix. The concrete cover thickness, the diameter and the shape of the lime nodule as well as the mechanical characteristics of concrete and lime are the key parameters influencing the development of internal pressure and hence controlling the risk of cracking or pop-out. In order to study the effect of lime into cementitious concretes, laboratory investigations and modelling have been performed and show that the minimum cover thickness necessary to avoid the development of the pop-out phenomenon is estimated of the order of half the diameter of the inclusion. This is coming from the observation that expansion happens inside the porosity of the hydrated lime Ca(OH)2: ESEM and DRX analysis confirm the effect of confinement in the development of crystals. [less ▲]

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See detailInfluence of cement and aggregate type on thaumasite formation in concrete
Nielsen, peter; Sven, Nicolai; Darimont, Anne ULg et al

in Cement & Concrete Composites (2014), 53

In this study the influence of binder type on the formation of thaumasite in mortars made with expanded clay lightweight aggregates (LWA) was examined. For this purpose mortar prisms (20x20x160mm) were ... [more ▼]

In this study the influence of binder type on the formation of thaumasite in mortars made with expanded clay lightweight aggregates (LWA) was examined. For this purpose mortar prisms (20x20x160mm) were made with different binders and expanded clay lightweight aggregate or quartz sand, which after 28 days of curing in water were exposed to a 2.37 % Na2SO4 solution. The length and weight change of the prisms was recorded in triplicate as a function of time of exposure to dry-wet cycles in the sulphate solution or deionised water, at a temperature of 5 ± 1°C. The influence of the binder type on the expansion of the prisms in the 2.37 % Na2SO4 solution with dry and wet cycling can be ordered from strong to weak as follows: (1) CEM I + limestone filler, (2) CEM I, (3) CEM I + fly ash, (4) CEM III. The use of specific cements or cement blends can clearly inhibit the formation of thaumasite (and/or ettringite). The influence of the aggregate type (quartz versus LWA) on the sulphate reaction is more difficult to determine because the porosity of LWA can accommodate the growing sulphate crystals. All the mortar prisms made with quartz aggregate were bent or broken after 21 to 24 weeks exposure to the sulphate solution, while most mortar prisms made with expanded clay aggregate were still intact. The only exception being the mortar prisms containing limestone filler. The latter disintegrated between 24 and 34 weeks of exposure to the sulphate solution. The expansion of the prisms made with CEM I and CEM I + fly ash levelled off between 50 and 100 weeks of exposure to the sulphate solution. The prisms made with CEM III showed minimal expansion (≤ 0.1 %) after 3 years of exposure. The prisms exposed to demineralised water showed no or minimal expansion. The presence and mineralogy of secondary sulphate phases in the mortars was checked by XRD analysis and SEM-EDS analysis of (degraded) mortar prisms. In most cases a solid solution of ettringite-thaumasite was observed. Based on the composition, treatment and expansion of the different mortar prisms, key factors controlling the formation of thaumasite or a solid solution of thaumasite-ettringite are discussed. [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 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 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 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 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 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 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 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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See detailEvaluatie van de gevolgen van de aanwezigheid van kalknodules in beton - Gedetailleerd verslag
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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See detailEvaluation de l'effet de la présence de nodules de chaux dans les bétons - Conclusions
Courard, Luc ULg; Darimont, Anne ULg; Degée, Hervé ULg

Report (2010)

La contamination d’origine (0.7% du poids des granulats) a été amortie d’un facteur 100 durant les étapes de fabrication des granulats et de mise en œuvre des bétons. La pollution maximale observée sur ... [more ▼]

La contamination d’origine (0.7% du poids des granulats) a été amortie d’un facteur 100 durant les étapes de fabrication des granulats et de mise en œuvre des bétons. La pollution maximale observée sur chantier est de 0.006 % du poids des granulats. Sur chantier, les pop-out sont peu nombreux, les nodules de chaux sont de petite taille et les éclats de faible profondeur. Aucune fissuration n’affecte le béton. Cette étude conclut, sur la base du scénario du pire et avec une probabilité avoisinant la certitude, que la contamination ne présente pas de risque en termes de durabilité et de stabilité des ouvrages. Nous entendons par-là, que le risque de perte de résistance et le risque sur la stabilité et la durabilité des éléments de structure (dalles, voiles, poutres) liés à la présence des nodules sont tellement minimes qu’ils sont en réalité nettement plus faibles que ceux qui résultent de la variabilité normale tolérée pour les propriétés des bétons, en rapport avec les conditions de chantier. Après hydratation, les nodules densifiés de portlandite n’exercent plus de pression et se comportent comme de simples granulats. Les risques liés à la contamination des bétons par les nodules de chaux sont donc exclusivement de nature esthétique et concernent une profondeur maximale de 2 à 4 cm. [less ▲]

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See detailEvaluation de l'effet de la présence de nodules de chaux dans les bétons - Rapport détaillé
Courard, Luc ULg; Darimont, Anne ULg; Degée, Hervé ULg

Report (2010)

La contamination d’origine (0.7% du poids des granulats) a été amortie d’un facteur 100 durant les étapes de fabrication des granulats et de mise en œuvre des bétons. La pollution maximale observée sur ... [more ▼]

La contamination d’origine (0.7% du poids des granulats) a été amortie d’un facteur 100 durant les étapes de fabrication des granulats et de mise en œuvre des bétons. La pollution maximale observée sur chantier est de 0.006 % du poids des granulats. Sur chantier, les pop-out sont peu nombreux, les nodules de chaux sont de petite taille et les éclats de faible profondeur. Aucune fissuration n’affecte le béton. Cette étude conclut, sur la base du scénario du pire et avec une probabilité avoisinant la certitude, que la contamination ne présente pas de risque en termes de durabilité et de stabilité des ouvrages. Nous entendons par-là, que le risque de perte de résistance et le risque sur la stabilité et la durabilité des éléments de structure (dalles, voiles, poutres) liés à la présence des nodules sont tellement minimes qu’ils sont en réalité nettement plus faibles que ceux qui résultent de la variabilité normale tolérée pour les propriétés des bétons, en rapport avec les conditions de chantier. Après hydratation, les nodules densifiés de Portlandite n’exercent plus de pression et se comportent comme de simples granulats. Les risques liés à la contamination des bétons par les nodules de chaux sont donc exclusivement de nature esthétique et concernent une profondeur maximale de 2 à 4 cm. [less ▲]

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See detailA new test to assess the concrete susceptibility to "the decay" of the bridge deck slabs
Gilles, Pierre; Demars, Philippe; Dondonné, Eric et al

Scientific conference (2008, June)

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See detailThe degradation of the bridge deck slabs in Belgium mainly involves alkali-aggregate reactions
Demars, Philippe; Gilles, Pierre; Dondonné, Eric et al

Scientific conference (2008, June)

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See detailMix stability as a criterion for optimizing the granular composition to improve concrete durability – an application
Willem, Xavier; Courard, Luc ULg; Darimont, Anne ULg et al

in Marchand, J.; Bissonnette, B.; Gagné, R. (Eds.) et al Advances in Concrete through Science and Engineering (2006, September)

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See detailRe-alkalinization of carbonated concrete by means of alkaline migration
Darimont, Anne ULg; Gilles, Pierre; Dondonne, E.

in Bulletin des Laboratoires des Ponts et Chaussées (2006), 261(avril mai juin), 121-129

In Belgium, a number of girder bridge deck slabs have over the past several years been displaying major degradations (delamination, disaggregation, etc.) capable, in time, of leading to slab perforation ... [more ▼]

In Belgium, a number of girder bridge deck slabs have over the past several years been displaying major degradations (delamination, disaggregation, etc.) capable, in time, of leading to slab perforation. This form of degradation, called "rotting of bridge deck slab concrete" is not uniformly distributed over the deck surface: deteriorated zones can be distinguished from intact zones and moreover are often associated with the presence of dark spots. On the lower surface of some such spots, the previously-carbonated concrete layer can sometimes once again display a pH of above 8.3. It will also be demonstrated that this anomaly may be attributed to a migration of alkaline through the concrete slab towards the lower surface, thereby causing a re-alkalinization of the carbonated layer and hence a rise in pH. [less ▲]

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See detailUse of municipal solid waste incineration residues in concrete pavement setts
Courard, Luc ULg; Degeimbre, Robert ULg; Darimont, Anne ULg et al

in Proceedings of CONMAT'05 and Midness Symposium (2005)

Valorisation of Municipal Solid Waste Incineration Residues - excluding ashes - is a positive advance in sustainable development : saving natural resources, decrease of wastes volume stored, reduction of ... [more ▼]

Valorisation of Municipal Solid Waste Incineration Residues - excluding ashes - is a positive advance in sustainable development : saving natural resources, decrease of wastes volume stored, reduction of energy consumption. If good conditions of incineration can be ensured and post-combustion treatments are realised, solid residues are in the form of granular materials usable in construction and civil engineering. Application for the fabrication of concrete pavement has been developed. Mechanical and physical performances of municipal solid waste incineration residues let us to replace a part of the granular skeleton and to obtain similar behaviour than for reference granular composition : splitting resistance, water absorption and resistance to abrasion are optimised. Leaching behaviour is also verified in order to avoid detrimental effect on the environment. Example of application is presented in “sleeping policeman” technique and durability of the structure is explained. [less ▲]

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See detailSome effects of limestone fillers as a partial substitute for cement in mortar composition
Courard, Luc ULg; Degeimbre, Robert ULg; Darimont, Anne ULg et al

in Banthia, N. (Ed.) Third International Conference on construction materials: performance, innovations and structural implications (2005)

Limestone filler is a raw material that is already used in several applications like paints, bricks, bituminous mixes, … Moreover, and particularly in Belgium, classical additions like fly ashes and blast ... [more ▼]

Limestone filler is a raw material that is already used in several applications like paints, bricks, bituminous mixes, … Moreover, and particularly in Belgium, classical additions like fly ashes and blast furnace slags become 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 blast furnace slag cement has been realized between 15 and 30% 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 concerned the mechanical properties, the evolution of the porosity and the durability. The K factor indicates a higher value and the porosity seems to be better in the case of 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, chloride penetration, sulphate resistance and carbonation rate show quite interesting behaviours, leading to the conclusion that this material needs again more investigations in order to define optimum application conditions in cementitous matrixes [less ▲]

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