Please use this identifier to cite or link to this item: http://repositorio.lnec.pt:8080/jspui/handle/123456789/1009827
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dc.contributor.authorMedeiros, S.pt_BR
dc.contributor.authorFernandes, I.pt_BR
dc.contributor.authorNunes, J. C.pt_BR
dc.contributor.authorSantos Silva, A.pt_BR
dc.contributor.authorSoares, D.pt_BR
dc.date.accessioned2017-08-21T15:50:14Zpt_BR
dc.date.accessioned2018-03-01T15:34:41Z-
dc.date.available2017-08-21T15:50:14Zpt_BR
dc.date.available2018-03-01T15:34:41Z-
dc.date.issued2016-04-23pt_BR
dc.identifier.urihttps://repositorio.lnec.pt/jspui/handle/123456789/1009827-
dc.description.abstractConcrete is one of the most widely used construction material in the world. However concrete structures can deteriorate during their lifetime due to material limitations, design and construction practices and severe exposure conditions. One of the causes of concrete deterioration is related to alkali-silica reactions (ASR) which are chemical reactions that occur between alkaline (Na+ and K+) and hydroxyl (OH-) ions in the cement paste and certain forms of silica in some aggregates. This deterioration phenomenon causes expansion and cracking that consequently reduces the life service of concrete structures. Basalts and other volcanic rocks have been found to be the cause of premature concrete structures deterioration in concrete in several countries, such as Japan, Iceland and Turkey, due to the occurrence of ASR. The characterization of the reactivity of volcanic aggregates in Azores has been implemented through the research project ReAVA (Characterization of Potential Reactivity of the Volcanic Aggregates from the Azores Archipelago: Implications on the Durability of Concrete Structures). Aggregates were selected and collected from a total of 13 places in 8 Islands. Corvo Island was the only exception due to the lack of local production. The program involved: (1) the petrographic characterization of the aggregates, (2) assessment of their performance in expansion tests and (3) site inspection of some existing large concrete structures in the Azores. The results of the lab tests show that one of the aggregates is potentially reactive. Also one of the concrete structures studied in this project evidenced some degradation, showing features that are very similar to ASR. This paper presents the results obtained on the characterization and performance of volcanic aggregates from Azores regarding the potential reactivity to alkalis using different methods and the concrete ASR diagnosis in a concrete structure.pt_BR
dc.language.isoengpt_BR
dc.publisherLRECpt_BR
dc.rightsrestrictedAccesspt_BR
dc.subjectAzores islandspt_BR
dc.subjectVolcanic aggregatespt_BR
dc.subjectPetrographypt_BR
dc.subjectASRpt_BR
dc.subjectConcretept_BR
dc.titleAlkali-silica reaction - A case study in the Azores Archipelago throught the ReAVA projectpt_BR
dc.typeworkingPaperpt_BR
dc.identifier.localedicaoS. Miguel - Açorespt_BR
dc.description.pages9ppt_BR
dc.description.commentsThe authors would like to acknowledge the financial support of Azorean Regional Government through the Regional Fund for Science (FRC - Fundo Regional para a Ciência) for the project ReAVA (ref.M5.2.2/I/05/2011). The analyses by SEM/EDS were performed at CEMUP which equipment was funded by the projects REEQ/1062/CTM/2005 and REDE/1512/RME/2005 of Portuguese Foundation for Science and Technology (FCT).The authors also acknowledge the LNEC support through the RE-Improve project and the contribution of construction companies especially Tecnovia Açores, Sanibritas and Marques Britas for allowing the access to the quarries for the aggregates study and also the contribution of airports of Portugal (ANA – Aeroportos de Portugal) for authorizing the access to the pavement of the airport runway. The first author also acknowledges the scholarship granted by the FRCT (refª: M3.1.A/F/BI/0000001/2012).pt_BR
dc.identifier.localFurnas, S. Miguel, Azorespt_BR
dc.description.sectorDM/NMMpt_BR
dc.identifier.proc0204/112/19701pt_BR
dc.identifier.conftitleInternational Workshop on NATURAL HAZARDS - NatHaz16pt_BR
dc.contributor.peer-reviewedSIMpt_BR
dc.contributor.academicresearchersSIMpt_BR
dc.contributor.arquivoNAOpt_BR
Appears in Collections:DM/NMM - Comunicações a congressos e artigos de revista

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