12 research outputs found

    Environmental and energy assessment of the use of Andesite in cement

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    The present study is a contribution to the research of new sources of supply of additions and raw materials in order to valorize local materials in the manufacture of cement. It consists in checking the environmental validity of the industrial use of andesite by evaluating the energy consumption of manufacturing andesitic cement. This evaluation was made on CEMI 52.5R type cement mortars whose basic constituent is clinker, with substitution rates of raw and calcined andesitic rock at 800 °C varying from 0-40%. and this through mechanical performance tests at several deadlines (2 days, 7 days, 28 days and 90 days). The results show that the analysis of the influence on the environment of this addition, in its raw state or calcined at 800 ° C, made it possible to say that globally the impact of andesite on the matrices seems positive to long term. The replacement of the cement by andesite systematically induces a reduction in the energy required to produce one ton of binder, due to the lower energy demand for grinding than that required for the thermal treatment of the clinker. Overall, the energy cost of andesite cement (in kWh per MPa compressive strength) is lower than that of ordinary cement for low rates of clinker replacement and obtaining cements with moderate strengths

    Environmental and energy assessment of the use of Andesite in cement

    No full text
    The present study is a contribution to the research of new sources of supply of additions and raw materials in order to valorize local materials in the manufacture of cement. It consists in checking the environmental validity of the industrial use of andesite by evaluating the energy consumption of manufacturing andesitic cement. This evaluation was made on CEMI 52.5R type cement mortars whose basic constituent is clinker, with substitution rates of raw and calcined andesitic rock at 800 °C varying from 0-40%. and this through mechanical performance tests at several deadlines (2 days, 7 days, 28 days and 90 days). The results show that the analysis of the influence on the environment of this addition, in its raw state or calcined at 800 ° C, made it possible to say that globally the impact of andesite on the matrices seems positive to long term. The replacement of the cement by andesite systematically induces a reduction in the energy required to produce one ton of binder, due to the lower energy demand for grinding than that required for the thermal treatment of the clinker. Overall, the energy cost of andesite cement (in kWh per MPa compressive strength) is lower than that of ordinary cement for low rates of clinker replacement and obtaining cements with moderate strengths

    Etude de la réactivité hydraulique d’un ciment bélitique synthétisé à basse température par la méthode sèche en utilisant un minéralisateur

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    Pour des raisons écologiques (réduction des émissions de CO2), les ciments bélitiques à faible teneur en alite ont fait l’objet de beaucoup de recherches ces dernières années afin de substituer le clinker Portland ordinaire. Ces recherches ont concernées la production du ciment bélitique à basse temperature et l’amélioration de son activité hydraulique, ainsi que l’étude de la durabilité des matériaux à base de ce ciment. Dans ce travail, le mélange cru des matières premières (calcaire et argile) du ciment bélitique a été substitué par un autre mélange composé de poussière de chaux hydraulique des ateliers d’ensachage et de boue de forage des puits de pétrole en Algérie. Le procédé de cuisson par voie sèche en utilisant 2% de sulfate de zinc (ZnSO4) comme minéralisateur a été adopté pour la fabrication de ce ciment bélitique (éco-ciment) à basse température (1100°C). L’analyse par diffraction des rayons X (DRX) a montré que la phase fortement réactive de la bélite (άL-C2S) a été stabilisée, ce qui montre la forte réactivité hydraulique de ce ciment bélitique. Les analyses par DRX, effectuées sur des pâtes du ciment bélitique synthétisé, et les essais physiques (temps de prise) et mécaniques sur des pâtes et mortiers, ont confirmé la réactivité hydraulique de ce ciment qui demeure similaire à celle du ciment de type CEM I 42,5

    Evaluation and improvement of pozzolanic activity of andesite for its use in eco-efficient cement

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    WOS:000325232600140International audienceThe search for new pozzolan sources for eco-efficient cement manufacture is the main goal of this study, which evaluates the pozzolanic activity of andesitic material existing in large quantities in Algeria. The improvement in the pozzolanic activity of the andesite was also studied by using mechanical and thermal processes. To evaluate the pozzolanic activity of natural and treated andesite, some pozzolanicity tests, namely the Frattini test, the saturated lime test, XRD, TGA and strength activity index, were used. Mortars of blended cements containing CEM I (52.5R and 42.5N) and 0% to 40% of natural or treated andesite were prepared in order to study the pozzolanic performance of andesite blended cement during hardening. The results show that natural andesite has a moderate pozzolanic reactivity enabling blended cements to be developed. Heat treatment at 800 C improved the andesite pozzolanicity but it remained too low in relation to the high cost of the calcination operation. The partial replacement of cement by andesite led to a decrease in the energy needed to produce a ton of binder. From a performance point of view, the energy cost (kW h/MPa) of binders made of andesite is especially interesting when lower performance cements are used. (C) 2013 Elsevier Ltd. All rights reserved

    Elaboration d’une Pouzzolane Artificielle à Base de la Zéolithe X Synthétisée à partir de Kaolin Naturel

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    Cette étude est une contribution à l’élaboration d’une nouvelle pouzzolane artificielle à base de zéolithe X synthétisée à partir de kaolin naturelle. Le choix de cette zéolithe revient à son pouvoir d’adsorption qui lui permet de réagir facilement avec la portlandite dans la pâte de ciment. La synthèse de cette zéolithe, sa caractérisation et les tests de sa pouzolanicité, ainsi que l’élaboration de ciment pouzzolanique à base de cette zéolithe et l’étude de ses caractéristiques physiques et mécaniques constituent l’objet de ce modeste travail. L’activité pouzzolanique de cette zéolithe a été déterminée par le test de chaux saturée, par diffraction des rayons X et par analyse thermique (ATG-DSC). Des essais physiques (temps de prise) et mécaniques (résistances à la compression et à la flexion) ont été effectués sur des pâtes et mortiers de ciment renfermant 0 à 20% de zéolithe synthétisée. Les résultats obtenus sont très satisfaisants et permettent de conclure que la zéolithe X synthétisée est fortement pouzzolanique et peut être utilisée pour élaborer un éco-ciment tout en réduisant les émissions de CO2 résultant de la fabrication du clinker largement substitué par cette zéolithe dans le ciment Portland

    Manufacture of rich-sulfoaluminate belite cement at low temperature from waste mixture by dry and hydrothermal processes

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    This study, within the framework of eco-cement development, aims to manufacture reactive belite-sulfoaluminate cement (BYF) as alternative to Portland cement (PC). This ecological cement is obtained at low temperature from a mixture of industrial wastes using two synthetic methods, dry and hydrothermal treatment. The main minerals of this cement are β-C2S and calcium sulfoaluminate (C4A3Š), the latter being very reactive, which provide high performances cementitious materials. The hydrothermal treatment of raw mixture led to reduce the burning temperature of clinker up to 1200 °C. The mineral phases of the produced cements and theirs pastes were identified and quantified by XRPD coupled with Rietveld method. The hydraulic reactivity of cement was studied using XRPD and thermal analyses. The resulting mortars are very reactive and develop more than 42 MPa of compressive strengths after 28 days.UMA18-FEDERJA-095 y P18-RT-720 (ambos cofinanciados FEDER
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