Comparison of Chloride-Induced Corrosion of Microsilica and ECC in the Offshore Piers' Concrete (Case Study: Wharves P3 & P4 of Imam Khomeini Petrochemical)

Abstract

The corrosion of reinforcements in the tidal zone leads to significant damage to offshore concrete piers. To overcome such damages, the quality of concrete and its mechanical properties should be improved. The aim of the present study is to identify and evaluate the causes and extent of corrosion observed in piers P3 & P4 in Imam Khomeini petrochemical. The concrete reinforced by microsilica and the ECC concrete are used to prevent corrosion. Some tests were conducted to determine the conditions of concrete piers in terms of reinforcement corrosion. Then, a reinforcement corrosion intensity test using Potentiostat involving a placement process was used, where the water-to-cement ratio was 38%; superplasticizers was 4%; and microsilica was 10% and 15%. The microsilica can serve as an alternative to the consumed cement and was measured according to the ASTM standards; Besides, it was exposed to aggressive conditions at different periods, and a concrete compressive strength test was performed. The results show that the compressive strength of concrete with microsilica 15% is nearly 25% higher than that of ECC, while for the control specimen, this value is about 42%. Regarding the corrosion intensity, the concrete with microsilica 15% has the minimum value compare to all three other samples. It is recommended to use this type of concrete to overcome the corrosion problem in piers P3 & P4 in Imam Khomeini petrochemical.