Effect of settlement cracks on corrosion initiation and rate in reinforced concrete

ABSTRACT

Factors such as paste content, concrete slump, compressive strength, and evaporation rate affect the tendency of concrete to crack, which can lead to corrosion and rapid deterioration in structures. There is some debate on the effect of narrow taperedcracks, such as settlement cracks, on corrosion of reinforcing steel. In this study, the effect of settlement cracks on chloride transport and corrosion initiation was evaluated. The cracks were narrower than 0.003 in. [0.08 mm] and tapered below the concrete surface, features that are difficult to reproduce with artificially-induced cracks. Cracks with widths as low as 0.001 in. (0.025 mm) and lengths as low as 2.25 in. (55 mm) resulted in early corrosion initiation in a majority of the specimens, although corrosion rates were lower than test specimens that had an artificially-induced crack above the reinforcing bars. The findings suggest that even relatively small cracks are potentially detrimental to service life.

KEYWORDS:

• Corrosion
• settlement cracking
• chlorides
• crack width
• reinforcing steel

Disclosure statement

No potential conflict of interest was reported by the author(s).