Influence of impressed current on the initiation of damage in reinforced mortar due to corrosion of embedded steel

Corrosion of steel in cementitious material is a slow process. Therefore in this study, accelerated corrosion tests were carried out by impressing current between steel embedded in mortar and a counter-electrode to study the process of corrosion leading to cracking in mortar. The specimens, which were made of mortar reinforced with steel, were immersed in solutions which contained or did not contain chlorides. Critical times with respect to the onset of corrosion can be defined in various ways by using either steel half-cell potential, or potential drop between embedded steel and a counter-electrode, or expansion of the mortar specimen. These parameters give quite similar critical times and are related to the development of corrosion products and microcracking. The results obtained provide information on corrosion kinetics of embedded steel when corrosion is accelerated by impressed current and show the similarities to natural corrosion pattern when solutions contain chlorides. (C) 2007 Elsevier Ltd. All rights reserved.