Title:
Corrosion of Steel Bars with Respect to Orientation in Concrete
Author(s):
Tarek Uddin, Nobuaki Otsuki, and Makoto Hisada
Publication:
Materials Journal
Volume:
96
Issue:
2
Appears on pages(s):
154-159
Keywords:
corrosion; reinforcing steels (bars); water-cement ratio
DOI:
10.14359/439
Date:
3/1/1999
Abstract:
Corrosion of steel bars (main steel and stirrup) with respect to the orientation in concrete is presented herein. A detailed study on macrocell and mircocell corrosion of steel bars in concrete was conducted on horizontal and vertical steels depending on the casting direction. The horizontal steel was divided into top and bottom halves. The study was conducted with chloride ions in concrete. Water-cement ratios were 0.5 and 0.7. The electrochemical investigations, and microscopic and physical observations of steel bars were performed. The laboratory investigations were verified with the long-term (23 years) exposure investigations on reinforced concrete beams. The study also focused on the influence of stirrup on macrocell formation of main steel and corrosion of plain and deformed steel bars. The study concludes that orientation of steel bars has a significant influence on macrocell and microcell corrosion of steel bars in concrete. Formation of gaps under the horizontal steels causes significant corrosion. Stirrups play an important role in increasing macrocell corrosion of main steel. It was found that deformed bars corroded more than plain bars.