Effect of admixtures in concrete on the corrosion resistance of steel reinforced concrete

The effect of admixtures, namely silica fume, latex, methylcellulose and short carbon fibers (in various combinations), in concrete on the corrosion resistance of steel reinforced concrete was assessed by measuring the corrosion potential and corrosion current density during immersion in Ca(OH) 2 and NaCl solutions. Silica fume (15% by weight of cement) was most effective for improving the corrosion resistance, due to decrease of water absorptivity, and not so much due to increase in electrical resistivity. Latex (20% by weight of cement) improved the corrosion resistance because it decreased the water absorptivity and increased the electrical resistivity. Methylcellulose (0.4% by weight of cement) improved corrosion resistance only slightly. Carbon fibers (0.5% by weight of cement) decreased the corrosion resistance due to decrease in electrical resistivity. However, the negative effect could be compensated by adding either silica fume or latex, which reduced the water absorptivity.