Strength Assessment of RCC Beams Subjected To Corrosion

Anand Kumar B.G, "Strength Assessment of RCC Beams Subjected To Corrosion", IRT Proceeding on national conference on Innovative Approaches in Civil Engineering, 7-8 April, 2012, published by Indian research transaction, India

The damage assessment of civil structural members is one of the most important and recently emerging fields in engineering. Deterioration of a structure may occur due to a host of factors such as poor workmanship, improper maintenance, atmospheric effects, accidents, natural calamities. Certain causes like environmental effects, natural calamities can not be controlled. Therefore, durability of concrete structures especially those exposed to aggressive environments is of great concern. In spite of many deterioration causes and factors have been investigated in turn corrosion of steel reinforcement was found to be one of the major deterioration problems. Thus, an Engineer may need to examine the state of reinforcement in structures for a number of reasons including assessment for change of use or exposure, routine maintenance, or investigating signs of distress. In turn, there is a requirement for a method that can determine simply, accurately and non-destructively not only whether corrosion of reinforcement is taking place but also its intensity and the rate of damage. The main aim of this paper is to assess and evaluate the corrosion condition of reinforced concrete beams by using Non-destructive test (NDT) methods such as Half-cell potential test, Rebound hammer test, and Ultrasonic pulse velocity test. Also another thrust of this pilot program is to establish a correlation between Rebound hammer number, and Ultrasonic pulse velocity variation versus concrete strength for different degree of corrosion in turn to interpret the effectiveness of degree of corrosion on NDT values as well as concrete compressive strength. For that a total of six reinforced concrete beams (150x150x1000) mm were considered. An impressed current was applied to beams with different degree of corrosion (5%, &10%) in order to accelerate steel corrosion. Mean while electrochemical measurements were carried out to obtain open circuit potential. Finally the results show that the Linear regression analysis is the best fit for the compressive strength prediction relationship by using Rebound hammer and Ultrasonic pulse velocity test at compression as well as tension side of reinforced concrete beam with different degree of corrosion (5%, &10% ).

1. Al-Sulaimani, G.J., Kaleemullah, M., Basunbul, I.A. and Rasheeduzzafar, "Influence of Corrosion and Cracking on Bond Behaviour and Strength of Reinforced Concrete Members", ACI Structural Journal, V.87, No.2, 1990, pp.220-231.
2. Deputat. J, "Non-destructive evaluation methods of material properties", Gamma (in Polish), Warszawa 1997.
3. Carino.N.J, Non-destructive Test Methods, Concrete Construction Engineering Handbook, ed. E. G. Nawy, CRC Press, 19.1-19.67.
4. Mehta, P. K., and Gerwick, B. C., "Cracking-Corrosion Interaction in Concrete Exposed to Marine Environment," Concrete International, V. 4, No.10, Oct. 1982, pp. 45-51.
5. Wang, K., and Monteiro, P. I., "Corrosion Products of Reinforcing Steel and their Effects on the Concrete Deterioration," Third CANMET/ACI international Conference on Performance of Concrete in Marine Environment, P. K. Mehta, ed., New Brunswick, Canada, Aug. 4-9, 1996, pp. 83-97.
6. Malhotra.V.M. "Insitu/Non-destructive testing on Concrete-A Global Review" (1984), Insitu/Nondestructive testing of Concrete, American Concrete Institute, Detroit.
7. Popovics, S., "Analysis of the concrete strength versus ultrasonic pulse velocity relationship", Materials Evaluation, V.59, No.2, 2001 pp.123-129.
8. Paulo.J.M.Monterio, Frank Morrison and William Frangos., "Non-destructive measurement of corrosion state of reinforcing steel in concrete", ACI materials Journal, V.95, No.6, 1998, pp.704-709.
9. ASTM C 876-87, "Standard Test Method for Half-Cell Potentials of Uncoated Reinforcing Steel in Concrete," ASTM, 1990, pp. 429-433.
10. Standard test method for Rebound Number of hardened concrete. In Annual Book of ASTM Standards, ASTM C 805-85. American Society for Testing and Materials, Detroit. 1994.

©2012 Indian Research Transaction

Published by Research Publications, India