Browsing by Author "Villarroel, M."

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    Assessing the effect of fish size on species distribution model performance in southern Chilean rivers
    (2019) Zamorano, D.; Labra, F.A.; Villarroel, M.; Lacy, S.; Mao, Luca; Olivares, M.A.; Peredo Parada, M.
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    Corrosion products of reinforcement in concrete in marine and industrial environments
    (ELSEVIER SCIENCE SA, 2009) Vera, R.; Villarroel, M.; Carvajal, A. M.; Vera, E.; Ortiz, C.
    The corrosion products formed on embedded steel in concrete under simulated marine and industrial conditions and natural marine environment were studied. A 0.50 water/cement ratio concrete was used concrete 3.5% NaCl and 180 g L(-1) of H(2)SO(4) with 70 ppm of chloride ions solutions were used to simulate the synthetic medium. The initial electrochemical variables of the steel and pH, chlorides and sulfates profiles were measured according to the concrete depth. The morphology of the corrosive attack was determined electron microscopy (SEM), and the composition of the corrosion products was determined via scanning zer and an X-ray diffractorneter (XRD). The protective power of the corrosion products was evaluated through anodic polarization curves in a saturated Ca(OH)(2) Solution. The results from XRD and SEM show that all the resulting corrosion products correspond to lepidocrocite, goethite and magnetite mixtures: moreover, akaganeite was also identified under natural and simulated marine environments. Siderite was only detected in samples exposed to a natural marine environment. Concerning the protective nature of the corrosion products, these show lower performance in a simulated industrial environment, where the corrosion rate of the steel is up to 1.48 mu m year(-1). (C) 2008 Elsevier B.V. All rights reserved.
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    DURACON: Effect of the Environment on Reinforced Concrete Durability. Results of Chile after 5 years of Exposure
    (PONTIFICIA UNIV CATOLICA CHILE, ESCUELA CONSTRUCCION CIVIL, 2009) Vera, R.; Villarroel, M.; Delgado, D.; Carvajal, A. M.; De Barbieri, F.; Troconis, O.
    This study presents the results obtained in Chile under the international project "Influence of Environmental Action in the durability of concrete, DURACON" that joins 11 countries (Argentina, Bolivia, Brazil, Chile, Colombia, Costa Rica, Mexico, Spain, Uruguay, Portugal and Venezuela) that began in 2002. The project considers the exposure of reinforced concrete specimens for at least 5 years at stations located in the marine environment (Valparaiso-PUCV) and urban (PUC-Santiago). The concrete specimens were designed with w/c 0.45 and 0.65 and characterized by determining the compressive strength and tensile strength, elastic modulus, resistivity, capillary absorption, absorption and total porosity. The corrosion of steel was evaluated by corrosion potential and corrosion current and depth of carbonation in the concrete to determine the critical onset corrosion.
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    DURACON: influencia de la acción del medio ambiente en la durabilidad del concreto. Parte 2. Resultados de Chile después de 5 años de exposición
    (2009) Vera, Raúl; Villarroel, M.; Delgado, D.; Carvajal Guerra, Ana María; De Barbieri, F.
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    Synergism of Extruded and Monolithic Co-Mo/γ-AL2O3-Sepiolite Catalytic Systems in the Hydrodesulphurization Reaction
    (2016) Baeza, P.; Villarroel, M.; Villanueva, R.; Gil Llambías, Francisco Javier; Ávila, P.