Reed Leaves Extract as Corrosion Inhibitor for Reinforcing Steel in Concrete

The effect of reed leaves extract (RLE) as an eco-friendly corrosion inhibitor for reinforcing steel in concrete immersed in 3.5% NaCl solution was investigated. The work was carried out using Linear polarization resistance, Potentiodynamic polarization, cyclic polarization, photographic examination, impressed voltage and compressive strength tests. Results obtained from Tafel polarization curves after 180 days immersion showed that corrosion rate was decreased and efficiency was increased with increasing of concentration of RLE inhibitor. The minimum corrosion rate was 2.259 μmpy with maximum efficiency of 76.98% at 0.5% RLE concentration (by cement weight). Also, the photographic study results indicated that inhibited surfaces are more smooth compared to control surface (without inhibitor). Cyclic Voltammetry curves showed that steel samples with RLE inhibitor have low tendency to pitting corrosion compared with control samples. On the otherhand, compressive strength test indicated that addition of RLE inhibitor to concrete mix increased compressive strength by 7.16 % at 0.5% concentration. Impressed voltage test showed that corrosion of reinforced steel bar initiated on the seventh day of experiment for control sample while on the eighteenth day for RLE sample at 0.5% concentration. The results of this study revealed that RLE acts as a good eco-friendly corrosion inhibitor.