Influence of Ca(NO2)2 on Sea Water Corrosion of Reinforcing Steel in Concrete
William H. Hartt and Arnold M. Rosenberg
Appears on pages(s):
calcium nitrite; corrosion; corrosion resistance; cracking (fracturing);cylinders; electric measuring instruments; reinforced concrete; reinforcing steels; sea water; serviceability.
Cylindrical reinforced concrete specimens, 102 mm. in diameter by 457 mm. and containing 0-4% Ca(N02)2 by weight of cement were partially submerged in sea water. A single 356 mm. length of no. 4 reinforcing steel was symmetrically positioned along the central axis of each specimen with an electrical lead penetrating the top surface. The corrosion state of the embedded steel was characterized by periodic electrochemical potential measurements, and it was considered that the onset of significant corrosion corresponded to a noble-to-active potential shift. Corrosion exposure of some specimens was terminated subsequent to potential becoming active, and these specimens were cracked open and the reinforcing steel examined. It was determined that the time for potential of the reinforcing steel to become active lengthened with increasing Ca(N02)2. Possible reasons for the effectiveness of Ca(N02)2, in mitigating reinforcing steel corrosion are presented, and significance of the present results with regard to serviceability of reinforced concrete in corrosive applications is discussed.