scholarly journals Experimental investigation of crack width variation along the concrete cover depth in reinforced concrete specimens with ribbed bars and smooth bars

Author(s):  
Chavin N. Naotunna ◽  
S.M. Samindi M.K. Samarakoon ◽  
Kjell T. Fosså
2016 ◽  
Vol 6 (3) ◽  
pp. 272-283
Author(s):  
Y. Hernández ◽  
O. Troconis de Rincón ◽  
A. Torres ◽  
S. Delgado ◽  
J. Rodríguez ◽  
...  

Relación entre la velocidad de corrosión de la armadura y el ancho de fisuras en vigas de concreto armado expuestas a ambientes que simulan el medio marino  RESUMENEsta investigación presenta una relación empírica entre la velocidad de corrosión de la armadura y la velocidad de ensanchamiento de fisuras por corrosión del recubrimiento de concreto en vigas, con o sin aplicación de carga. Se evaluaron vigas de concreto armado, expuestas a un proceso de corrosión natural mediante el rociado con solución salina al 3,5 %p/p de NaCl, para acelerar el proceso corrosivo de la armadura, mediante ensayos electroquímicos. El ancho de fisuras se evaluó mensualmente para estimar la relación existente entre éste y la pérdida de sección de la armadura. Los resultados demuestran que existe una relación directa entre la propagación del ancho de fisuras y la velocidad de corrosión, observando fisuras de mayor ancho en vigas cargadas.Palabras clave: corrosion; concreto armado; vigas cargadas; ancho de fisuras. Reinforcement corrosion rate and crack width relationship in concrete beams exposed to simulated marine environment ABSTRACTThis investigation presents an empirical correlation between the rebar corrosion rate and the corrosion-induced crack width propagation rate produced on beam's concrete cover, with or without load application to these beams. Reinforced concrete beams were evaluated, exposed to a natural corrosion process by spraying with 3.5 %w/w NaCl solution, to accelerate the rebar corrosion process, was performed with electrochemical tests. The beams corrosion-cracking evaluation was performed once every month, to determine the relation between crack width and the rebar corrosion loss. The results showed a direct relation between crack width propagation and rebar corrosion rate, showing wider cracks in the loaded beams.Keywords: corrosion; reinforced concrete; loaded beams; crack widths. Relação entre a velocidade de corrosão da armadura e a largura das fissuras em vigas de concreto armado expostas a ambientes que simulam o ambiente marinho RESUMOEsta pesquisa apresenta uma relação empírica entre a taxa de corrosão da armadura e a abertura de fissuras por efeito da corrosão da armadura em vigas de concreto, com ou sem aplicação de carga. Foram avaliadas vigas de concreto armado, expostas a um processo de corrosão natural por pulverização com solução salina a concentração de 3,5% de NaCl, para acelerar o processo de corrosão da armadura, mediante ensaios eletroquímicos. A abertura das fissuras foi avaliada mensalmente para estimar a relação entre ela e a perda de seção da armadura. Os resultados mostram que existe uma relação direta entre a propagação da abertura da fissura e a taxa de corrosão, observando a ocorrência de fissuras de maior abertura nas vigas sob carga.Palavras-chave: corrosão; vigas de concreto armado sob carga; abertura de fissuras. 


2012 ◽  
Vol 252 ◽  
pp. 17-22
Author(s):  
Chuan Wang ◽  
Li Li Sui ◽  
Qing Duo Hao ◽  
Qi Yu Lu

The different mechanical property determines the difference on cracking behavior between GFRP/steel wire composite rebar reinforced concrete beams and steel rebar reinforced concrete beams according to cracking mechanics. In order to study the cracking behavior of concrete beams reinforced with GFRP/ steel wire composite rebar, five simply-supported beams were tested under three-point static load. The test variables were beam section size and concrete cover depth. Based on analysis on the test results, the calculation methods of cracking capacity and maximum crack width were proposed, and the limit value of crack width was suggested.


2006 ◽  
Vol 302-303 ◽  
pp. 610-617
Author(s):  
Jia Jin Zheng ◽  
Xin Zhu Zhou ◽  
Shi Lang Xu

Crack width is a significant parameter for assessing service life of reinforced concrete structures in chloride-laden environments. Corrosion-induced concrete cracking is a predominant causal factor influencing premature degradation of reinforced concrete structures, incurring considerable costs for repairs and inconvenience to the public due to interruptions. This gives rise to the need for accurate prediction of crack width in order to achieve cost-effectiveness in maintaining serviceability of concrete structures. It is in this regard that the present paper attempts to develop a quasi-brittle mechanical model to predict crack width of chloride contaminated concrete structures. Assuming that cracks be smeared uniformly in all directions and concrete be a quasi-brittle material, the displacement and stress in a concrete cover, before and after surface cracking, were derived respectively in an analytical manner. Crack width, as a function of the cover depth, steel bar diameter, corrosion rate and time, was then determined. Finally, the analysis results were verified by comparing the solution with the experimental results. The effects of the cover depth, steel bar diameter and corrosion rate on the service life were discussed in detail.


Author(s):  
Jan Mlčoch ◽  
Jana Marková ◽  
Miroslav Sýkora

Abstract The contribution is focused on quantifying model uncertainty of crack width estimates for reinforced concrete beams. Predictions obtained by the model provided by the fib Model Code 2010 are compared with results of tests of beams having different longitudinal and shear reinforcement ratios and concrete cover. Trends of model uncertainty with basic variables are investigated.


Materials ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3478
Author(s):  
Shingo Asamoto ◽  
Junya Sato ◽  
Shinichiro Okazaki ◽  
Pang-jo Chun ◽  
Raktipong Sahamitmongkol ◽  
...  

Reinforced concrete bridges were visually surveyed in Japan, Thailand, and Vietnam to study the deterioration caused by internal steel corrosion under different climates, focusing on the concrete cover depth. Spalling or cracking arising from corrosion is likely where water is supplied. According to prior studies and our surveys, a concrete cover depth of more than 40 mm was found to prevent spalling, regardless of environmental conditions and structure age. Because water supply at steel is a key corrosion factor, it was hypothesised that under natural conditions, the water penetration in concrete would remain at a depth of approximately 40 mm. Our laboratory study examined water penetration under drying and wetting conditions. The results also suggested that under periodic rainfall conditions, the threshold of water penetration was not exceeded. The numerical study indicated maximum moisture evaporation to facilitate oxygen diffusion occurred at a depth of approximately 30–40 mm unless the concrete was exposed to continuous drying for more than one month. It was experimentally and numerically concluded that an adequate cover depth of greater than 40 mm could inhibit moisture and oxygen penetration at the steel, which supported the survey findings of cover depth effect on a high resistance to corrosion-induced deterioration despite an increase in service life.


2015 ◽  
Vol 784 ◽  
pp. 129-136
Author(s):  
Huu Tran ◽  
Chun Qing Li ◽  
Sujeeva Setunge

Prediction of time-to-cracking and crack-width of concrete cover provides useful information for decision making on maintenance and rehabilitation of reinforced concrete structures. Comparison of prediction models for time-to-cracking has been done in a recently published study, which indicated simple prediction models provide better good fit to various sets of experimental data than complex models. As a follow-up, this study uses published crack-width data to compare different models, developed in the literature to predict crack-width of concrete cover.


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