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DC Field | Value | Language |
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dc.contributor.author | Medeiros, S. | pt_BR |
dc.contributor.author | Fernandes, I. | pt_BR |
dc.contributor.author | Nunes, J. C. | pt_BR |
dc.contributor.author | Santos Silva, A. | pt_BR |
dc.contributor.author | Soares, D. | pt_BR |
dc.date.accessioned | 2017-08-21T15:50:14Z | pt_BR |
dc.date.accessioned | 2018-03-01T15:34:41Z | - |
dc.date.available | 2017-08-21T15:50:14Z | pt_BR |
dc.date.available | 2018-03-01T15:34:41Z | - |
dc.date.issued | 2016-04-23 | pt_BR |
dc.identifier.uri | https://repositorio.lnec.pt/jspui/handle/123456789/1009827 | - |
dc.description.abstract | Concrete 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.iso | eng | pt_BR |
dc.publisher | LREC | pt_BR |
dc.rights | restrictedAccess | pt_BR |
dc.subject | Azores islands | pt_BR |
dc.subject | Volcanic aggregates | pt_BR |
dc.subject | Petrography | pt_BR |
dc.subject | ASR | pt_BR |
dc.subject | Concrete | pt_BR |
dc.title | Alkali-silica reaction - A case study in the Azores Archipelago throught the ReAVA project | pt_BR |
dc.type | workingPaper | pt_BR |
dc.identifier.localedicao | S. Miguel - Açores | pt_BR |
dc.description.pages | 9p | pt_BR |
dc.description.comments | The 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.local | Furnas, S. Miguel, Azores | pt_BR |
dc.description.sector | DM/NMM | pt_BR |
dc.identifier.proc | 0204/112/19701 | pt_BR |
dc.identifier.conftitle | International Workshop on NATURAL HAZARDS - NatHaz16 | pt_BR |
dc.contributor.peer-reviewed | SIM | pt_BR |
dc.contributor.academicresearchers | SIM | pt_BR |
dc.contributor.arquivo | NAO | pt_BR |
Appears in Collections: | DM/NMM - Comunicações a congressos e artigos de revista |
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