Several studies have shown the feasibility and thermal potential of gypsum plaster with microspheres of PCM, but very few of them investigated an approach with practical and standards concern. In this work, different characterizations are performed according to European standards on a standard gypsum plaster and two different gypsum plasters formulated with 20 wt.% of PCM microspheres. A material is experimentally made by mixing conventional gypsum and PCM microspheres, whereas the other is an already prepared commercial mix. For the laboratory material, the addition of PCM increases the consistency of the fresh paste of plaster. In order to reach a consistency in agreement with the standards more water is required. This higher amount of water causes further issues on the densification and cohesion properties. In contrary, the properties of the commercial mix are closer to a common plaster. It is therefore assumed that the commercial material incorporates thinner additives. In view of these results, it is assumed that most of the drawbacks due to the addition of PCM microspheres in gypsum plasters could effectively be encountered by adequate addition of additives in order to reduce the amount of water, and binding resins in order to improve the adhesion and mechanical properties.

Résumé -Une accélération de l'affinage des merrains de chêne est possible par un traitement dans une solution d'enzymes naturels. Son effet sur les caractéristiques physiques, mécaniques et sur le potentiel d'absorption d'une solution hydro-alcoolique par le bois nécessitait cependant d'être testé. Des éprouvettes normalisées ont été extraites de 150 merrains, sélectionnés dans trois tonnelleries réparties sur le territoire français, sur base du critère de largeur des cernes usité en tonnellerie. Les facteurs de classification : tonnellerie, classe de largeur des cernes et traitement ont été utilisés dans l'analyse statistique. Le facteur tonnellerie influence le module d'élasticité et la contrainte de rupture en flexion statique mais pas les autres caractéristiques physiques et mécaniques du bois. L'amélioration des propriétés du bois est étroitement liée à l'augmentation des largeurs des cernes des éprouvettes. Le traitement enzymatique n'affecte pas significativement les caractéristiques physiques et mécaniques du bois de chêne, à l'exception de la dureté et, dans une moindre mesure, du potentiel d'absorption, ou une influence négative est observée. Compte tenu du très faible impact sur les caractéristiques du bois de chêne (Quercus sp.) destiné à la tonnellerie et des apports positifs du traitement enzymatique sur l'affinage des merrains, ce traitement pourrait constituer une alternative pour éviter un stockage de longue durée des merrains. chêne / merrain / enzyme / caractéristiques physiques / caractéristiques mécaniquesAbstract -Properties of shooks ageing by a treatment in a solution of natural enzymes. A speeding up of the ageing of shooks is possible by a treatment with a solution of natural enzymes. However its repercussion on physical, mechanical characteristics of wood and on its absorption potential of an hydro-alcoholic solution must be tested. Normalized samples have been extracted from 150 shooks selected on a ring width criteria from three cooperages located on different supplying area in France. The three factors cooperage, ring width class and treatment are used for statistical analysis. The cooperage factor, reflection of the supply area of each of them, affect the young modulus and the modulus of rupture in static bending but not the other characteristics. The improvement of the wood properties is closely linked to the ring width increase of the samples. The enzymatic treatment has no significant effect on physical and mechanical characteristics of oak wood, except on the hardness and, to a lesser extent, on the absorption potential. Considering the absence of negative effect on characteristics of shooks and the positive contribution of enzymatic treatment on their ageing, this treatment could bring a very interesting economical alternative permitting to avoid long lasting storage of the shooks before assembly.oak / shook / enzyme / physical characteristic / mechanical characteristic

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