Effect of corrosion on the tensile properties of steel bars in cracked HPC containing CNI

An evaluation of the effects of pitting corrosion on the tensile properties of reinforcing bars embedded in pre-cracked high performance concrete (HPC) containing calcium-nitrite corrosion inhibitor (CNI) was performed. Twenty-seven HPC slabs were prepared at three different w/cm ratios and CNI additions of 0, 12.5, and 25 L/m³. The slabs were pre-cracked at 0.0, 0.25, and 0.50 mm crack widths and exposed to a marine environment. After seven years, the reinforcing bars were retrieved, visually inspected and the deepest pit, D _PIT, caused by pitting corrosion was measured. Then, the yield load, P_YIELD, ultimate load, P_ULTIM; and elongation at rupture, δ, were determined. The results show that bars extracted from un-cracked low w/cm concretes containing CNI presented marginally reduction on the tensile properties. Conversely, in bars extracted from pre-cracked specimens, reductions of maximum 18% on the ultimate load and 82% on the elongation, as a consequence of pitting corrosion, were found.