Influence of Transverse Crack Opening Size on Chloride-Induced Corrosion of Steel Bars in Concrete

Abstract

This study evaluated the influence of crack opening size on the corrosion initiation and propagation of reinforcing steel bars in precracked concrete as a result of chloride ingress. Uncracked (reference) and transversely cracked reinforced concrete beam specimens were prepared for laboratory experiments. Specimens were fabricated with crack mouth opening widths of 0.1, 0.3, and 0.7 mm (0.004, 0.012, and 0.028 in.). A ponding well was installed on top of the specimens above the cracks; specimens were subjected to two-week wet and two-week dry cycles with 3% by weight NaCl solution in the pond. Electrochemical tests and visual inspections were conducted to evaluate the condition of the reinforcing bars. The results after approximately 550 days of the experiment showed that steel in specimens with a 0.7 mm (0.028 in.) crack opening exhibited more severe corrosion than steel in specimens with a 0.3 mm (0.012 in.) crack opening. Corrosion behavior of steel bars in specimens with 0.1 mm (0.004 in.) crack opening was distinct. Bars in these specimens had high corrosion rates initially, but as time progressed, the corrosion rate decreased significantly.