4 resultados para Cement industry

em Universidad Politécnica de Madrid


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Natural cement was patented in 1796 but it didn’t arrive in Spain until 1835. No one knows exactly where the production started in Spain, because it emerged independently at the same time in many places. Most of these outbreaks are concentrated in the north and northwest of Spain: Basque Country (Zumaya and Rezola) and Catalonia (San Celoní and San Juan de las Abadesas).Natural cement was extensively used to decorate historical buildings during the nineteenth and beginning of twentieth century in Madrid. It was the building material which realised the architects and builders dreams of mass-produced cast elements in a wide variety of styles. Its arrival replaced traditional materials that were used previously (lime, gypsum and hydraulic limes). However, its use was not extended in time, and soon it was replaced by the use of artificial Portland cements. During 20th century this building material disappeared from use. What remains is it’s memory, in thousands and thousands of “stone witnesses” in our cities. Final properties of the cement largely depend on raw materials used and its combustion temperature. However, it was characterised by an easily implementation on facade masonry, fast-setting (about 15 minutes), good resistance , an agreeable structural consistency and colour.This article aims to show first steps, evolution and decay of Natural Cement Industry in Spain and its application in Madrid.

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In Spain, natural zeolites have been only found in the volcanic areas of Canary Islands (San Gil, M.M., 1959). However, several years ago the study of the South Eastern region of continental Spain (Cabo de Gata) revealed the presence of a deposit of mordenite being industrially commercialized as bentonite. The deposit San José-Los Escullos is located in the concession registered as Los Murcianos, managed by Bentonitas Especiales, S.A. (BENESA) who was extracting bentonite while ignoring the presence of the zeolite. The name San José-Los Escullos refers to the discovery of mordenite in this deposit. The deposit is located in a volcanic area, constituted by pyroxenic andesites, breccias, tuffs, pyroclasts with andesitic and dacitic composition, largely altered by the hydrothermal solutions. The recent discovery of this zeolite with mordenite content up to 97%, has changed the initial vision about that deposit, and new possible uses of this mineral in the pozzolanic cement industry are foreseen. This work intends to give preliminary data on the characterization of this zeolite according to X-ray diffraction (XRD), ICP analyses, and scanning electron microscopy (SEM), as well as to emphasize the pozzolanic properties of this material, using both chemical and mechanical tests.

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The aim of this study was to determine if the soils, waters and plants from the Aliaga dump contained polycyclic aromatic hydrocarbons (PAHs) and their quantification.The results showed that PAHs concentrations in soils are in general higher than the reference levels from the Spanish legislation. Waters and plants contained PAHs but in low concentrations. The possible actions for remediation (photodegradation and bioremediation) seem to be unviable here because of the large volume of materials involved, although its use as an additive for the cement industry and derivatives can be considered. It is proposed that fluorantene in waters, and phenanthrene and benzo[ghi]perilene in soils be considered as pollutants as well as to study the incorporation of PAHs to plants. Key-words: Polycyclic aromatic hydrocarbons, soil, plant and water contamination, fly- ash, power plant. RESUMEN: El objetivo de este estudio fue determinar y cuantificar los hidrocarburos policíclicos aromáticos (PAHs) en los suelos, plantas y aguas de la Escombrera de Aliaga. La concentración de PAHs en las cenizas supera, en general, los valores establecidos en la legislación española.Las aguas y plantas contienen PAHs, aunque en concentraciones bajas. La remoción de los materiales para someterlos a fotodegradación y biorremediación es inviable debido al gran volumen de la escombrera, aunque se plantea su uso como aditivo en la fabricación de productos derivados del cemento. Se propone incluir el fenantreno y benzo[ghi]perileno en la normativa de suelos, así como el naftaleno en la de aguas y la elaboración de una legislación sobre la incorporación de estos compuestos a las plantas.

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GRC is a cementitious composite material made up of a cement mortar matrix and chopped glass fibers. Due to its outstanding mechanical properties, GRC has been widely used to produce cladding panels and some civil engineering elements. Impact failure of cladding panels made of GRC may occur during production if some tool falls onto the panel, due to stone or other objects impacting at low velocities or caused by debris projected after a blast. Impact failure of a front panel of a building may have not only an important economic value but also human lives may be at risk if broken pieces of the panel fall from the building to the pavement. Therefore, knowing GRC impact strength is necessary to prevent economic costs and putting human lives at risk. One-stage light gas gun is an impact test machine capable of testing different materials subjected to impact loads. An experimental program was carried out, testing GRC samples of five different formulations, commonly used in building industry. Steel spheres were shot at different velocities on square GRC samples. The residual velocity of the projectiles was obtained both using a high speed camera with multiframe exposure and measuring the projectile’s penetration depth in molding clay blocks. Tests were performed on young and artificially aged GRC samples to compare GRC’s behavior when subjected to high strain rates. Numerical simulations using a hydrocode were made to analyze which parameters are most important during an impact event. GRC impact strength was obtained from test results. Also, GRC’s embrittlement, caused by GRC aging, has no influence on GRC impact behavior due to the small size of the projectile. Also, glass fibers used in GRC production only maintain GRC panels’ integrity but have no influence on GRC’s impact strength. Numerical models have reproduced accurately impact tests.