Tensile and fatigue behavior of corroded rebars

Zhang, Weiping; Song, Xiaoqian; Gu, Xianglin; Li, Shibin

doi:10.1016/j.conbuildmat.2012.02.071

Cited by 217 publications

(99 citation statements)

References 8 publications

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“…The corroded rebars used in these studies had been affected by natural corrosion processes, such as the ones removed from real structures (Papadopoulos et al 2011;Zhang et al 2012), or by artificial corrosion processes, including the electric method (Almusallam 2001;Cairns et al 2005;Du et al 2005;Lee and Cho 2009;Zhang et al 2012) and salt spray (Apostolopoulos et al , 2013; Lee and Cho 2009;Papadopoulos et al 2007Papadopoulos et al , 2011. In spite of the different corrosion methods, the various studies have similarly demonstrated that corrosion may decrease yield and ultimate tensile strengths, and significantly reduce ultimate strain or elongation.…”

Section: Introductionmentioning

confidence: 99%

Evaluation Method of Tensile Behavior of Corroded Reinforcing Bars Considering Radius Loss

Qiao

Nakamura

Yamamoto

et al. 2015

ACT

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The tensile behavior of plain round reinforcing bars corroded with various radius losses along their length is investigated experimentally and analytically. In the experiments, various corrosion topographies are simulated through accelerated electric corrosion tests using bare rebar specimens and different cathode arrangements. The tensile performance of the corroded specimens is then studied using a digital image processing method, showing that tensile degradation resulting from corrosion is closely related to radius loss variability. For the analysis, a numerical model based on the rigid body spring method incorporated with a truss network is proposed for the evaluation of tensile behavior in consideration of radius loss. Good agreement with the test data is obtained with the proposed model, which offers an accurate method of estimating the residual tensile capacity of corroded rebars.

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Section: Introductionmentioning

confidence: 99%

Evaluation Method of Tensile Behavior of Corroded Reinforcing Bars Considering Radius Loss

Qiao

Nakamura

Yamamoto

et al. 2015

ACT

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“…Papadopoulos et al [17] carried out tests of tensile strength in 96 test specimens extracted from hundreds of years' old edifications in Greece. Recently, study of Zhang et al [16] compared the behavior to tensile strength and the fatigue or protruding reinforcing steel in edification with more than 30 years in China and Balestra et al [11] evaluated the effect of the corrosion degree in the effective and nominal resistance of protruding reinforcing steel naturally corroded. Generally, independently if the corrosion method of bars is accelerated in laboratory or under natural conditions, the mentioned studies point for a decrease in values regarding yield strength, ultimate strength, final stretching and ductility, as the loss of mass of the corroded rebar increases.…”

Section: Introductionmentioning

confidence: 99%

“…Studies of Almussallan [12], Apostolopoulos et al [10] and François et al [8] may be mentioned among the researches contemplating the reinforcement corrosion made in laboratory. In the perspective of reinforcement corroded obtained from real structures, it is possible to mention studied from Palssom e Mirza [5], Papadopoulos et al [17], Zhang et al [16] and Balestra et al [11]. The methodology used by Almussallan [12] consists in applying a current in steel bars embedded in concrete in order to accelerate the corrosion process.…”

Section: Introductionmentioning

confidence: 99%

“…Thus, the old foundations were discarded, and the protruding reinforcing steel and a block of foundation being collected to researches. It is important to highlight that the protruding reinforcing steel remained buried in the soil during decades, being its corrosion Effect of corrosion degree on mechanical properties of reinforcements buried for 60 years process natural, in other words, without the influence of procedures accelerated in laboratory that may not properly reflect the strength expected from naturally corroded bars [11,16]. This fact allows a realistic quantitative analysis of the effects of corrosion determined by means of gravimetric loss and decrease of the diameter of the bars over the mechanical properties of the protruding reinforcing steel.…”

Section: Introductionmentioning

confidence: 99%

“…It has been observed that most of the works regarding the evaluation of the mechanical properties of corroded rebars is about accelerated corrosion tests in laboratory environment. It must be highlighted that, depending on the methodology used to promote the reinforcement corrosion -salt chambers for instance -those works may not generate the formation of the passivating layer that cover the reinforcement inside the concrete due to the alkaline pH of the mean; this results in an uniform attack, and, in consequence, differences regarding the corrosion mechanism [6,8,10,[12][13][14][15][16]. In this context, the reinforcement corrosion by the action of chlorides is characterized as being by pits, since the chlorides have the capacity of breaking locally the existing passivating layer.…”

Section: Introductionmentioning

confidence: 99%

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Effect of corrosion degree on mechanical properties of reinforcements buried for 60 years

Balestra

Lima

Mendes

et al. 2018

Rev. IBRACON Estrut. Mater.

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ResumoThis paper studies the influence of the corrosion degree calculated by the mass loss and by the smaller diameters on the yield strength, ultimate strength and final elongation. Reinforcements buried and naturally corroded for 60 years were studied. The mechanical properties of the protruding reinforcing steel were compared to reference bars, which also remained buried for 60 years, but without going through the corrosion process. Micrographs, besides the chemical composition and the characterization of the aggressiveness of the soil were realized. The micrographs and the chemical composition show the presence of pits in the reinforcements and sulfur contents for steel above the prescriptions of the time when the foundations were initially implement, respectively. The results also show that the effects of pitting corrosion on the mechanical properties of the naturally corroded bars may not be adequately expressed by the mass loss. This type of corrosion (pits) produces geometric variations in the cross sections along the length of the test specimens, generating stress gradients between successive sections. This has a noticeable impact on the mechanical properties of the reinforcements. In general, the effects of corrosion are more pronounced on the ductility of the reinforcement. Regarding the aggressiveness of the soil, high corrosion rates were identified in the reinforcement, even with the soil being classified as essentially non-corrosive.Keywords: reinforcement corrosion, durability, mass loss, smallest diameter, corrosion degree, mechanical properties.Este artigo estuda a influência do grau de corrosão, calculado pela perda de massa e pelos menores diâmetros, sobre a resistência ao escoamento, limite de resistência e alongamento final em armaduras corroídas naturalmente. Essas armaduras permaneceram enterradas por 60 anos. As propriedades mecânicas das armaduras de espera foram comparadas às de barras de referência, que também permaneceram enterradas por 60 anos, mas sem sofrer o processo de corrosão. Foram realizadas micrografias, além da determinação da composição química e da caracterização da agressividade do solo onde as armaduras estavam enterradas. As micrografias e a composição química mostram a presença de pites nas armaduras e teores de enxofre acima das prescrições recomendadas para o aço na época de execução das fundações, respectivamente. Os resultados também mostram que os efeitos da corrosão por pites sobre as propriedades mecânicas das barras corroídas naturalmente podem não ser adequadamente expressos pela perda de massa. Esse tipo de corrosão (pites) produz variações geométricas nas seções transversais ao longo do comprimento dos corpos de prova, gerando gradientes de esforços entre seções sucessivas, que impactam de forma notória sobre suas propriedades mecânicas. De uma maneira geral, os efeitos da corrosão são mais pronunciáveis sobre a ductilidade das barras. Com relação à agressividade do solo, altas velocidades de corrosão foram identificadas nas armaduras, mesmo com o...

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Veränderung der mechanischen Kenngrößen von Betonstabstählen durch chloridinduzierte Korrosion

Baumgärtner

Fraundorfer

Dauberschmidt

et al. 2019

Beton und Stahlbetonbau

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Die Dauerhaftigkeit chloridexponierter Stahlbetonbauteile wird maßgeblich durch das Korrosionsverhalten des Bewehrungsstahls bestimmt. Hat ein Eintrag von Chloriden in kritischer Konzentration in das Bauteil stattgefunden, kann eine Lochfraßkorrosion initiiert werden. Die durch die Korrosion auftretenden, sehr lokalen Materialabträge können in kurzer Zeit zu hohen Querschnittsverlusten der Bewehrung führen. Für die Instandsetzungsplanung steht der/die Sachkundige PlanerIn vor der Aufgabe, Art und Umfang der Instandsetzungsmaßnahme festzulegen. Dabei stellt sich auch die Herausforderung, vorhandene Querschnittsverluste zielsicher beurteilen zu können. Eine exakte Bestimmung des Querschnittsverlusts auf der Baustelle ist jedoch aufgrund der Narbengeometrie nur schwer möglich, weshalb Querschnittsverluste häufig visuell abgeschätzt werden. Auch stellt sich die Frage, ob durch Lochfraßnarben Kerbspannungen verursacht werden, die einen Einfluss auf die Zugtragfähigkeit haben und zu abweichenden Festigkeitswerten im Vergleich zur reinen Querschnittsbetrachtung führen. Weiterhin zu hinterfragen ist der Einfluss der lokalen Schädigung auf das Dehnungsverhalten des Bewehrungsstahls und damit auf eine duktile Versagensankündigung des Bauteils. Zur besseren Beurteilbarkeit lochfraßgeschädigter Bewehrung wurden an der Hochschule München Versuche an Betonstählen mit einem weiten Schädigungsspektrum infolge chloridinduzierter Korrosion durchgeführt. Hierzu wurden natürlich geschädigte Betonstabstähle verschiedenen Durchmessers aus einer Tiefgarage der 1960er Jahre entnommen und im Labor künstlich geschädigte Proben hergestellt. Die Stahlproben wurden auf ihr optisches Erscheinungsbild, den Restquerschnitt sowie das Dehnungsverhalten und die statische Restzugtragfähigkeit hin untersucht.

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Tensile and fatigue behavior of corroded rebars

Cited by 217 publications

References 8 publications

Evaluation Method of Tensile Behavior of Corroded Reinforcing Bars Considering Radius Loss

Evaluation Method of Tensile Behavior of Corroded Reinforcing Bars Considering Radius Loss

Effect of corrosion degree on mechanical properties of reinforcements buried for 60 years

Veränderung der mechanischen Kenngrößen von Betonstabstählen durch chloridinduzierte Korrosion

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