Browsing by Author "Millano, V."

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    Concrete Carbonation in Ibero-American Countries DURACON Project: Six-Year Evaluation
    (2015) Troconis de Rincon, O.; Montenegro, J. C.; Vera, R.; Carvajal, A. M.; Mejia de Gutierrez, R.; Del Vasto, S.; Saborio, E.; Torres-Acosta, A.; Perez-Quiroz, J.; Martinez-Madrid, M.; Martinez-Molina, W.; Alonso-Guzman, E.; Castro-Borges, P.; Moreno, E. I.; Almeraya-Calderon, F.; Gaona-Tiburcio, C.; Perez-Lopez, T.; Salta, M.; de Melo, A. P.; Martinez, I.; Rebolledo, N.; Rodriguez, G.; Pedron, M.; Millano, V.; Sanchez, M.; de Partidas, E.
    Concrete carbonation data from 16 test sites in 9 countries (Bolivia, Chile, Colombia, Costa Rica, Mexico, Spain, Uruguay, Portugal, and Venezuela) were compared to identify concrete performance due to carbonation at natural exposure conditions after almost six years of exposure. This research is part of the DURACON project ("Effect of the environment on reinforcement durability"), a long-term Ibero-American project intended to correlate the influence of urban and marine meteorochemical parameters on the performance of reinforced concrete structures. Environmental parameters were measured following the ISO 9223 standard. Concrete was physically characterized by the results of compressive strength, elastic modulus, total and effective porosity, and water absorption resistance (Fagerlund method) laboratory tests. Concrete specimens (with and without steel reinforcement bars-rebars) were prepared for electrochemical and physical/mechanical/chemical tests using materials available in each country. Concrete composition was kept similar between specimens by following strict preparation protocols. Two water/cement (w/c) ratios were used: 0.45 w/c ratio concrete had a minimum cement content of 400 kg/m(3); and 0.65 w/c ratio concrete had a minimum 28-day compressive strength of 210 kg/cm(2). Materials were type I Portland cement, siliceous sand, and crushed rock as coarse aggregates (13-mm maximum nominal size). After six years of exposure, corrosion potentiality and probability analysis of the reinforcement at the different sites indicated the concrete prepared in Venezuela to have the highest probability of experiencing carbonation-induced reinforcement corrosion. The concrete prepared at the Cali, Colombia, site had the lowest probability. Carbonation aggressiveness was found to be highest at tropical sites, with the Venezuela sites exhibiting the most aggressive conditions among the participating countries.
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    Effect of the marine environment on reinforced concrete durability in lberoamerican countries: DURACON project/CYTED
    (2007) de Rincon, O. Troconis; Sanchez, M.; Millano, V.; Fernandez, R.; de Partidas, E. A.; Andrade, C.; Martinez, I.; Castellote, M.; Barboza, M.; Irassar, F.; Montenegro, J. C.; Vera, R.; Carvajal, A. M.; de Gutierrez, R. M.; Maldonado, J.; Guerrero, C.; Saborio-Leiva, E.; Villalobos, A. C.; Tres-Calvo, G.; Torres-Acosta, A.; Perez-Quiroz, J.; Martinez-Madrid, M.; Almeraya-Calderon, F.; Castro-Borges, P.; Moreno, E. I.; Perez-Lopez, T.; Salta, M.; de Melo, A. P.; Rodriguez, G.; Pedron, Miguel; Derregibus, M.
    This work presents some of the results from the project: "Effect of the environment on reinforcement durability" (DURACON) in its first two-years period, which investigates the influence of urban and marine meteorochemical parameters on the performance of reinforced concrete structures. The results presented in this investigation are from 21 marine test sites only (no urban environments are included), distributed among I I countries (Argentina, Bolivia, Brazil, Chile, Colombia, Costa Rica, Mexico, Spain, Uruguay, Portugal and Venezuela). The environment was evaluated using ISO Standard 9223 and the concrete was characterized by measuring compressive strength, elastic modulus, total and effective porosity, chloride permeability according to ASTM standards, as well as the effective porosity and resistance to water absorption using the Fagerlund method. To that effect, concrete specimens (with and without reinforcement) were prepared for electrochemical and physical/mechanical/chemical tests using the existing materials in each participating country, following strict procedures which enabled the preparation of similar concrete samples. Two water/cement (w/c) ratios (0.45 and 0.65) were selected, where the concrete with 0.45 w/c ratio had to have a minimum cement content of 400 kg/m(3) and the one with 0.65 w/c ratio a compressive strength of 210 kg/cm(2). Type I Portland cement, siliceous sand, and crushed rock as coarse aggregates (13-mm maximum nominal size) were used. After a one-year exposure, the results of the corrosion potentiality and probability analysis of the reinforcement in the different test stations showed that, for marine atmospheres, the most aggressive environment to induce steel corrosion was at Portugal's Cabo Raso station, and the least aggressive one was at Chile's Valparaiso station. These results are comparable with the ones found using electrochemical measurements, after a two-year exposure. (C) 2007 Elsevier Ltd. All rights reserved.