Deterioration progress and performance reduction of 40-year-old reinforced concrete beams in natural corrosion environments

Dasar, Amry; Hamada, Hiroyuki; Sagawa, Yasutaka; Yamamoto, Daisuke

doi:10.1016/j.conbuildmat.2017.05.162

Cited by 50 publications

(12 citation statements)

References 21 publications

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“…Nesse âmbito, alguns estudos vêm sendo realizados em ambientes marítimos, com condições de exposição naturais (CHALEE; JATURAPITAKKUL; CHINDAPRASIRT, 2009;DASAR et al, 2017;MARIC et al, 2017;VALIPOUR et al, 2013). Esses estudos são considerados mais adequados para avaliar a penetração de íons cloreto no concreto e prever a vida útil desse tipo de estrutura, apesar de demandarem períodos de exposição superiores aos necessários em ensaios acelerados.…”

Section: Introductionunclassified

Penetração de cloretos em concretos expostos em zona de atmosfera marinha por um período de 9 anos

2021

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Resumo A corrosão de armaduras é a manifestação patológica mais recorrente em estruturas de concreto armado, despertando maior preocupação em regiões litorâneas devido à presença de íons cloreto. Isso posto, destaca-se a carência de dados da concentração de cloretos de concretos em condição natural de exposição, principalmente na zona de atmosfera marinha. Dessa forma, este trabalho teve como objetivo avaliar os perfis de cloretos de blocos de concreto moldados com teores de substituição de sílica ativa de 5% (CP V_5SA) e 10% (CP V_10SA) quanto à massa de cimento e a relações a/agl de 0,45, 0,55 e 0,65. Os concretos permaneceram expostos em zona de atmosfera marinha por um período de 9 anos na cidade de Tramandaí, Rio Grande do Sul. Inicialmente, foram retiradas amostras pulverulentas dos blocos de concreto para posterior determinação da concentração de cloretos solúveis em água. No tocante à corrosão de armaduras, a utilização de teores de sílica ativa em percentuais de 5% e 10% é eficiente na redução do ingresso de cloretos; baixas relações a/agl apresentaram concentrações superficiais mais elevadas, em contrapartida, à medida que a profundidade em relação à superfície do concreto aumenta, há uma redução nesses teores. Além disso, o trabalho evidenciou que a redução da relação a/agl e a incorporação de sílica ativa se mostraram medidas eficazes na redução da concentração de cloretos ao longo do tempo.

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Penetração de cloretos em concretos expostos em zona de atmosfera marinha por um período de 9 anos

2021

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“…In most countries, there are old bridges that require maintenance, renovation, or reconstruction [ 3 ]. In the literature, it is possible to find many interesting investigations related to the process of testing and repairing old concrete bridges [ 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 ] or to the structural analysis of old bridges [ 16 , 17 , 18 , 19 , 20 , 21 , 22 ]. Reconstruction and renovation of old bridge structures and adaptation to new traffic loads are complex issues often requiring not only the experience of civil engineers, but also that of the scientific community.…”

Section: Introductionmentioning

confidence: 99%

A 95-Year-Old Concrete Arch Bridge: From Materials Characterization to Structural Analysis

Ambroziak

Malinowski

2021

Materials

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The structural analysis of a 95-year-old concrete arch bridge located in Jagodnik (Poland) is performed in this paper, in order to check its behavior under today’s traffic loads. The mechanical properties of both the concrete and the reinforcement are investigated by testing cores and bar stubs extracted from the bridge. Structural analysis confirms that the bridge meets today’s load requirements in terms of bearing capacity, serviceability state, and that the adopted structural improvements (a new deck slab on top of the existing structure and a layer of mortar to protect the surface of the old concrete) are effective. In this way, the 95-year-old arch bridge was given a new life. The structural improvements show how combining numerical modelling and laboratory tests can contribute to the preservation of an old—though fairly simple—and valuable structure, otherwise destined to demolition, with both environmental and economic benefits.

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“…Dasar et al (2017) tested performance reduction of 40-year-old reinforced concrete beams in natural corrosion environments and reported that for every 1% of local cross-sectional loss in the tensile steel bars, a 0.9% reduction in the load-carrying capacity of the reinforced concrete beams occurs. Rodriguez et al (as cited inDasar et al 2017) had reported that a corrosion degree of about 14% caused beam strength to decrease by 23%.…”

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confidence: 99%

Adapting River Bridge Infrastructures To Climate Change

Ifelola¹

2021

Preprint

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Climate change forecasts project up to 20% increase in precipitation for southern Ontario based on several climate change scenarios and models and an unpredictable change an average wind speed that may range from 5% reduction to 15% increase by the year 2100 compared to 1971 to 2000 reference period. Average annual air temperatures are predicted to increase between 2.5 and 3.7°C by 2050 from baseline average between 1961 and 1990. This research studied the impact of climate change on bridge infrastructure using the Portage bridge on the Ottawa river in southern Ontario as a case study. Result shows that increase in precipitation due to climate change will cause 0.3m/s increase in stream velocity and about 0.85m increase in water level for a 100-year storm. This increase will result in scour depths at bridge piers to increase by 0.86 m while bending moments on piers increased by 21 kNm. Shear forces also increased by 43 kN.

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Deterioration progress and performance reduction of 40-year-old reinforced concrete beams in natural corrosion environments

Cited by 50 publications

References 21 publications

Penetração de cloretos em concretos expostos em zona de atmosfera marinha por um período de 9 anos

Penetração de cloretos em concretos expostos em zona de atmosfera marinha por um período de 9 anos

A 95-Year-Old Concrete Arch Bridge: From Materials Characterization to Structural Analysis

Adapting River Bridge Infrastructures To Climate Change

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