Corrosion Behavior of Reinforcing Steel Embedded in Fly Ash Concrete

Concrete specimens measuring 12 in by 5 in by 3 in were prepared with binary concrete mixtures, in which fly ash was replaced for 20% of the ordinary Portland cement. A water to cementitious ratio of 0.41 was used. The specimens had 0.3 in concrete cover and were reinforced with single rebar. For ponding, different size of solution reservoirs were used, ranging from 2.5 cm to 17.5 cm. NaCl solution (10% by weight) was poured into the solution reservoirs. Accelerated chloride transport technique was employed, and this was continued for a week to a few months depending on the values of the off-rebar potential observed for each embedded specimen. The effect of rebar length under the reservoir for fly ash containing binary blended concrete mixes was examined. In this study, two different types of electrochemical measurements named as EIS and LPR were performed to monitor the values of rebar potential and corrosion current. The corrosion propagation was observed for at least 400 days. Sometimes, corrosion initiated several weeks after the removal of accelerated chloride transport approach. According to the experimental findings, it was observed that the corrosion current value increases with the length of the solution reservoir, except for a rebar embedded in specimens with a solution reservoir of 7.5 cm.