Browsing by Author "Hami, B."

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    Dielectric behavior study of thermosetting matrices loaded
    (2012) Irekti, Amar; Hami, B.; Aribi, Chouaib; Bezzazi, B.
    The present study was prospective in nature and its purpose is twofold. It consists, on the one hand, to identify and characterize mineral fillers, secondly, to determine the dielectric properties of materials prepared using the epoxy resin mixed with local inorg anic fillers , very rich in silica such that: sandy, pozzolan, cullet and a small calcium carbonate amount. This application allows us to use the matrix developed as an electrical insulator. The results of our study show that the use of fillers further im proves the dielectric properties of these matrices. After 32 days of conditioning, the values of capacitance and resistance obtained are very remarkable. Comparing our results with previous work with the addition of pure silica, we note that our composites have better properties at a low cost. The hygro - thermal influence is much less important fo r the loaded resin. Our composites may be subject to external environmental influences and they have a range of wide usage in dielectric materials
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    Pérennisation des ouvrages en génie civil : diagnos tic et inspection des bétons d’egouts
    (2012) Oualit, M.; Abadlia, Mohamed Tahar; Hami, B.
    La durabilité des bétons dans les réseaux d'assaini ssement est principalement affectée par l’action combinée, chimique (sels, sulfates, acides...), mécaniques (poinçonnement, abrasion...) et biologiques (bactéries aérobies, anaérobies...) provoquant une détérioration souvent de la matrice cimentaire. Ces dégradations sont souvent aggravées en fonction de la vitesse, la nature, la concentration et le pH ai nsique les conditions environnementales aux alentours (taux d’oxygène, empérature...etc). L’objectif de ce travail qui a été réalisé à l’INSA de Rennes consiste à effectuer une étude sur la dégradation et les facteurs responsables d’altération du béton employé dans le réseau d’égouts de la ville de Rennes. Ainsi, des échantillons prélevés dans différentes zones (radier, medium et toit) d’une conduite ont été analysés à l’aide de moyens d’investigation afin de mettre en évidence l’état d’endommagement interne due aux effluents et externe (sol) de résea u ainsi que les modifications chimiques et minéralogiques enregistrées. Ces essais sont complé tés par une caractérisation physique et mécanique. Dans cet article, nous présentons les résultats de l’inspection d’un tronçon dont les sollicitations prédominantes sont en majorité chimiques et abrasiv es. Cette étude met clairement en évidence la très fort e anisotropie des dégradations aussi bien internes qu’externes. Enfin, des ecommandations seront proposées en adéquation avec l’environnement ainsi qu’une évaluation de la perte de performance des conduits
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    Rheological behavior of epoxy resin filled fume silica
    (2014) Irekti, Amar; Bezzazi, Boudjema; Aribi, Chouaib; Hami, B.
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    Static and cyclic behavior of concrete reinforced with materials composite
    (Université M'Hamed Bougara Boumerdes, 2013) Irekti, Amar; Hami, B.; Aribi, C.; Abadlia, Mohamed Tahar
    This work includes the test results of static and cyclic compression specimens of plain concrete and reinforced by several folds of woven fiberglass. The static compression tests were performed at a constant speed with gradual increase of the load. The results are expressed by curves representing the change of stress as a function of the strain to failure. The results give us three phases of behavior: a phase behavior similar to that of a homogeneous and elastic material resulting in an almost linear relationship between stress and strain. The second phase of development of shattered concrete that leads to progressive curvature of the curve until the maximum stress (σmax) for a certain amount of strain (ε), and third in imposing increases distortion, we can get a decreasing curve corresponding to the accentuation of the rupture, that is to say in the development of fracture surfaces and cracking more or less widespread. The cyclic compression tests were conducted under load imposed on a percentage of the maximum load in static fracture, with a change in the number of cycles for each set of specimens. The results of cyclic compression tests show that the loss of stiffness to failure of the specimen is divided into three phases: in the first phase shows a gradual reduction of stiffness in the early rounds in the second phase decreased rigidity becomes slow, and finally in the third phase, the loss of stiffness abruptly accelerates to failure of the specimen