Effect of leaching on carbonation resistance and steel corrosion of cement-based materials

The effect of leaching on carbonation resistance of cement-based materials and steel corrosion in concrete is experimentally investigated. In order to investigate effect of leaching on carbonation, cement-based materials were exposed to three different leaching conditions. Exposure to leaching conditions was undertaken for 6 months and the specimens were subsequently kept in accelerated carbonation condition for 40 days. The results indicated that the preceding exposure to leaching increased the subsequent carbonation depth of the cement-based products. In order to investigate effect of leaching on corrosion initiation of steel bar inside concrete, reinforced concrete specimens were exposed to the continuously flowing water. Half-cell potential and corrosion current density were measured to monitor the corrosion activity. The monitoring was continued until 475 days of exposure. Although both HPC and i(corr) did not give any sign of corrosion, it was found by visual observation that the steel bars had been corroding. (C) 2012 Elsevier Ltd. All rights reserved.