The corrosion state of steel bars embedded in concrete specimens prepared with blast furnace cement and with Portland cement blended with fly ash, containing light and ordinary aggregates, was determined both in the atmosphere and in artificial sea water. The techniques used measured polarization resistance (Rp), corrosion potential, electrical resistivity and polarization curves. The most interesting results were obtained with the measurements of Rp, by means of which the corrosion rate was calculated, and with potential determination. Once more it has been shown that corrosion potential values strongly depend on the environment and are not necessarily related to the corrosion state; very low potentials do not indicate always a situation of corrosion risk. Moreover, the type of aggregate used seems to have a great influence on the corrosivity of the concrete. The corrosion rate values, determined following the Stern and Geary technique, showed that there is a remarkable difference between the specimens exposed to the atmosphere and those in sea water, after as little as 1 year, even though the corrosion rate values are very low. This technique may be considered the most reliable currently available to evaluate the corrosion state of a structure, and in particular, to determine corrosion initiation time.
A study of reinforcement behaviour in concrete structures using electrochemical techniques
PROVERBIO, Edoardo;
1993-01-01
Abstract
The corrosion state of steel bars embedded in concrete specimens prepared with blast furnace cement and with Portland cement blended with fly ash, containing light and ordinary aggregates, was determined both in the atmosphere and in artificial sea water. The techniques used measured polarization resistance (Rp), corrosion potential, electrical resistivity and polarization curves. The most interesting results were obtained with the measurements of Rp, by means of which the corrosion rate was calculated, and with potential determination. Once more it has been shown that corrosion potential values strongly depend on the environment and are not necessarily related to the corrosion state; very low potentials do not indicate always a situation of corrosion risk. Moreover, the type of aggregate used seems to have a great influence on the corrosivity of the concrete. The corrosion rate values, determined following the Stern and Geary technique, showed that there is a remarkable difference between the specimens exposed to the atmosphere and those in sea water, after as little as 1 year, even though the corrosion rate values are very low. This technique may be considered the most reliable currently available to evaluate the corrosion state of a structure, and in particular, to determine corrosion initiation time.Pubblicazioni consigliate
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