A Study on corrosion performance of steel in concrete under accelerated condition

Abstract

Corrosion of rebar embedded in concrete exposed to aggressive environment is one of the significant durability problems encountered in reinforced concrete structures. Exposure of reinforced concrete structures in chloride environment is generally considered as one of the aggressive conditions. In the present work the results of an experimental investigation is presented wherein the performance of concrete specimens made with different types of binder and w/b ratios has been evaluated by performing the accelerated corrosion test. The different types of binder used are ordinary Portland cement (OPC) and OPC with 20% fly ash replacement (OPC+FA). The three w/b ratios included in the study are 0.50, 0.55 and 0.60. Only one type of steel i.e. Thermex TMT steel has been used in the preparation of specimens. The prismatic concrete specimens with a centrally embedded steel bar have been prepared from the above binder, steel and w/b ratios. The specimens were immersed in 3% NaCl solution during the accelerated corrosion test. The measured parameters include the current response at the onset of crack appearance on the surface and the corresponding corrosion initiation time including the chloride content at the rebar level. Further the half-cell potential test was also conducted on the specimens after completion of accelerated corrosion test. On the basis of outcome obtained, the performance of specimens made with two types of binder at different w/b ratios has been evaluated.