International Journal of Civil and Structural Engineering Research ISSN 2348-7607 (Online) Vol. 7, Issue 2, pp: (13-23), Month: October 2019 - March 2020, Available at: www.researchpublish.com
Residual Strength Capacity of Corroded and Coated Reinforcing Bars Corrosion Performance on the Flexural Strength of Reinforced Concrete Members Nwaobakata Chukwuemeka1, Charles Kennedy2, Sule Samuel3 1,3
Department of Civil Engineering, University of Port Harcourt, Port Harcourt, Nigeria ,
2
Faculty of Engineering, Department of Civil Engineering, Rivers State University, Nkpolu, Port Harcourt, Nigeria Authors E-mail: 1makus20002000@gmail.com, 2ken_charl@yahoo.co.uk, 3samvictory@yahoo.com
Abstract: Cracks reduced the overall strength and stiffness of concrete structures and accelerate the ingress of aggressive ions, leading to other types of concrete deterioration and resulting in further cracking. Aims: The study investigated the effectiveness of naturally occurring inorganic products of garcinia kola extracts (exudates / resins) as a protective membrane to reinforcing steel embedded in concrete. Members were immersed in severe corrosive environment and accelerated for 150days with examinations on changes of the mechanical properties of steel. Obtained flexural failure load percentile value of -29.0031% against 40.85115% and 39.32435% non-corroded and garcinia kola exudates coated specimens. Midspan deflection percentile value of 57.26586% against -36.4134% and -34.915% non-corroded and coated specimens. Average yield strength, of 460MPa, derived into 100% with 0.00% of percentile value. Average ultimate tensile percentile value of -10.0738% against 11.2023% and 11.58322% of non-corroded and coated specimens. Average strain ratio percentile value of -10.9146% against 12.25184% and 15.75587% of non-corroded and coated specimens. Average elongations percentile value of -41.3245% against 70.42903% and 74.90969% for non-corroded and coated specimens. Collated results of corroded members showed high yield strength with low applied load, high midspan deflection and elongation. Low flexural failure load with high yield. Indications showed that the attributes possessed by corroded members resulted from corrosion attacked on the surface properties of reinforcing steel and reduction in general mechanical properties of steel. Collated results from exudates / resins coated members exhibited low flexural failure load over corroded members with high, low midspan deflection over high in corroded, little elongation over high in corroded. Indications showed that coated members possessed resistance characteristics to corrosion penetration. Results from noncorroded (Controlled) members have high values of flexural failure load, low midspan deflection and yield strength, strain ratio and elongation over all corroded members. Keywords: Corrosion, Corrosion inhibitors, Flexural Strength, Concrete and Steel Reinforcement.
1. INTRODUCTION The manifestation of corrosion in reinforced concrete structures has resulted to two severe principal forms of spalling and cracking of concrete cover resulting from unrestrained corrosion yield and local pitting of reinforcement at the anode which caused great reduction of the bar cross-sectional area. Reinforced concrete structures built within the coastal marine environment is at most risk of chloride induced corrosion due to the high presence of salt water. The formation of surface films covering the metal, while generally protective, can give rise to localized corrosion attack and pitting (Scully [1], [Bertolini et al.[2], Lounis et al. [3], Elsener [4]), concluded that there is instantaneous film formation in steel in an oxidizing atmosphere such as air, and once the formation of layer is noticed, metal is "passivated" and the oxidation or "rusting" rate will slow down to less than 0.04 mills per year (mpy).
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