Corrosion of Reinforced Concrete

Title :
Influence of calcium nitrite inhibitor and crack width on corrosion of steel in high performance concrete subjected to a simulated marine environment

Authors :
Pedro Montesa, Theodore W. Bremnera, Derek H. Listerb

Abstract :

The effects of calcium nitrite based corrosion inhibitor (CNI) and crack width on the corrosion process of steel reinforcing bars in high performance concrete were investigated. A 34 full factorial design was developed considering water to cement ratio, fly ash percent, CNI and cracked condition as factors. The response was the corrosion current density measured using the linear polarization resistance technique. Small-scale concrete slabs containing steel reinforcement were cast in concrete with a cover depth of 20 mm. The slabs were subjected to a simulated marine environment with two cycles of wetting and drying per day. The specimens were also visually inspected on a regular basis. It was found that CNI alone, in general, has no effect in decreasing corrosion, and that the crack condition of the specimens strongly affects the corrosion process. A significant effect of crack width on corrosion was also found. Furthermore, non-detrimental effect of CNI on corrosion of specimens containing fly ash was detected.

Keywords :
Calcium nitrite corrosion inhibitor, Cracked concrete, Fly ash, High performance concrete, Water to cement ratio

Source :