Corrosion propagation in cracked and uncracked concrete

The penetration of species that cause corrosion in Reinforced Concrete (RC) such as chloride ions, oxygen, carbon dioxide and moisture into concrete is governed by both the quality and condition of the cover concrete. The presence of cracks in the concrete cover may therefore aggravate the problem of corrosion in RC structures. This study focuses on both cracked and uncracked reinforced concrete beam specimens made using Ordinary Portland Cement (OPC) and 50/50 OPC/Corex slag blend. Crack widths of 0.4 mm, 0.7 mm and incipient cracks were investigated using 100 × 100 × 500 mm long beam specimens made with water/binder (w/b) ratios of 0.40 and 0.55. A constant concrete cover to steel of 40 mm was used for all the specimens. The tests focused on chloride-induced corrosion, using 5% NaCl solution, in order to investigate the influence of cracks on corrosion propagation. Preliminary results indicate that binder type, w/b ratio and the presence of cracks on the concrete surface influence the corrosion rate.