Efficiency of cathodic prevention to control corrosion in seawater mixed concrete

Large amount of potable water is used in construction industry. Due to shortage of potable water, use of seawater for both mixing and curing concrete seems to be an ideal alternative. However, major drawback of using seawater in concrete is large amount of chloride present in it, which leads to corrosion of embedded reinforcement in concrete. The main objective of the present study is to explore use of Cathodic Prevention (CPre) technique to control corrosion and successfully use seawater for making concrete. In the present study, three types of specimens were tested, i.e. (i) mixed with potable water, (ii) mixed with seawater, and (iii) mixed with seawater and with CPre to compare corrosion rate in seawater mixed concrete and to check efficiency of CPre to control it. Corrosion in specimens was monitored using both direct current (HCP and LPR) and alternating current (ac) based (EIS) technique. Effectiveness of CPre is monitored both in terms of 100 mV decay criterion and using EIS. The results show that application of the CPre technique just after casting of concrete can allow successful use of seawater for making steel reinforced concrete. Moreover, compared to dc techniques, EIS technique provides more detailed and accurate data during monitoring of steel corrosion, CPre and it is more helpful in identifying prevalent corrosion control mechanisms in seawater mixed concrete.