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Permeability of Concrete with Recycled Concrete Aggregate and Pozzolanic Materials under Stress

The research reported herein studied the permeability of concrete containing recycled-concrete aggregate (RA), superfine phosphorous slag (PHS), and ground granulated blast-furnace slag (GGBS) with and without stress. Test results showed that the chloride diffusion coefficient of RA concrete (RAC) w...

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Autores principales: Wang, Hailong, Sun, Xiaoyan, Wang, Junjie, Monteiro, Paulo J.M.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: MDPI 2016
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5502916/
https://www.ncbi.nlm.nih.gov/pubmed/28773376
http://dx.doi.org/10.3390/ma9040252
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author Wang, Hailong
Sun, Xiaoyan
Wang, Junjie
Monteiro, Paulo J.M.
author_facet Wang, Hailong
Sun, Xiaoyan
Wang, Junjie
Monteiro, Paulo J.M.
author_sort Wang, Hailong
collection PubMed
description The research reported herein studied the permeability of concrete containing recycled-concrete aggregate (RA), superfine phosphorous slag (PHS), and ground granulated blast-furnace slag (GGBS) with and without stress. Test results showed that the chloride diffusion coefficient of RA concrete (RAC) without external loads decreased with time, and the permeability of RAC is much lower than that of the reference concrete due to the on-going hydration and the pozzolanic reaction provided by the PHS and GGBS additives in the RAC mixture. The permeability of chloride under flexural load is much more sensitive than that under compressive load due to the differences in porosity and cracking pattern. At low compressive stress levels, the permeability of chloride decreased by the closing of pores and microcracks within RAC specimens. However, in a relatively short time the chloride diffusion coefficient and the chloride content increased rapidly with the increase of compressive stress when it exceeded a threshold stress level of approximate 35% of the ultimate compressive strength. Under flexural stress, the chloride transport capability increased with the increase of stress level and time. At high compressive and flexural stress levels, creep had a significant effect on the permeability of chloride in the RAC specimens due to the damage from the nucleation and propagation of microcracks over time. It is apparent that mortar cracking has more of a significant effect on the chloride transport in concrete than cracking in the interfacial transition zone (ITZ).
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spelling pubmed-55029162017-07-28 Permeability of Concrete with Recycled Concrete Aggregate and Pozzolanic Materials under Stress Wang, Hailong Sun, Xiaoyan Wang, Junjie Monteiro, Paulo J.M. Materials (Basel) Article The research reported herein studied the permeability of concrete containing recycled-concrete aggregate (RA), superfine phosphorous slag (PHS), and ground granulated blast-furnace slag (GGBS) with and without stress. Test results showed that the chloride diffusion coefficient of RA concrete (RAC) without external loads decreased with time, and the permeability of RAC is much lower than that of the reference concrete due to the on-going hydration and the pozzolanic reaction provided by the PHS and GGBS additives in the RAC mixture. The permeability of chloride under flexural load is much more sensitive than that under compressive load due to the differences in porosity and cracking pattern. At low compressive stress levels, the permeability of chloride decreased by the closing of pores and microcracks within RAC specimens. However, in a relatively short time the chloride diffusion coefficient and the chloride content increased rapidly with the increase of compressive stress when it exceeded a threshold stress level of approximate 35% of the ultimate compressive strength. Under flexural stress, the chloride transport capability increased with the increase of stress level and time. At high compressive and flexural stress levels, creep had a significant effect on the permeability of chloride in the RAC specimens due to the damage from the nucleation and propagation of microcracks over time. It is apparent that mortar cracking has more of a significant effect on the chloride transport in concrete than cracking in the interfacial transition zone (ITZ). MDPI 2016-03-30 /pmc/articles/PMC5502916/ /pubmed/28773376 http://dx.doi.org/10.3390/ma9040252 Text en © 2016 by the authors; Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC-BY) license (http://creativecommons.org/licenses/by/4.0/).
spellingShingle Article
Wang, Hailong
Sun, Xiaoyan
Wang, Junjie
Monteiro, Paulo J.M.
Permeability of Concrete with Recycled Concrete Aggregate and Pozzolanic Materials under Stress
title Permeability of Concrete with Recycled Concrete Aggregate and Pozzolanic Materials under Stress
title_full Permeability of Concrete with Recycled Concrete Aggregate and Pozzolanic Materials under Stress
title_fullStr Permeability of Concrete with Recycled Concrete Aggregate and Pozzolanic Materials under Stress
title_full_unstemmed Permeability of Concrete with Recycled Concrete Aggregate and Pozzolanic Materials under Stress
title_short Permeability of Concrete with Recycled Concrete Aggregate and Pozzolanic Materials under Stress
title_sort permeability of concrete with recycled concrete aggregate and pozzolanic materials under stress
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5502916/
https://www.ncbi.nlm.nih.gov/pubmed/28773376
http://dx.doi.org/10.3390/ma9040252
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AT sunxiaoyan permeabilityofconcretewithrecycledconcreteaggregateandpozzolanicmaterialsunderstress
AT wangjunjie permeabilityofconcretewithrecycledconcreteaggregateandpozzolanicmaterialsunderstress
AT monteiropaulojm permeabilityofconcretewithrecycledconcreteaggregateandpozzolanicmaterialsunderstress