Corrosion potential of coated steel bar embedded in sea-water mixed mortar

¹ Department of Civil Engineering, Universitas Muhammadiyah Yogyakarta, Jalan Brawijaya, Kasihan, Bantul, Indonesia
² Maintenance Engineering Group, P.S. Mitsubishi Construction Co. Ltd., Harumi Center Building 3F, 2-5-24, Tokyo, Japan
³ Departemen Teknik Sipil, Vocational College, Universitas Gadjah Mada, Jalan Yacaranda Sekip Unit IV, Bulaksumur, Blimbing Sari, Caturtunggal, Depok, Sleman, Indonesia

^* Corresponding author: pinta.astuti@ft.umy.ac.id

Abstract

Corrosion of embedded steel bars in concrete structures is the most impactful deterioration case in the world therefore many researchers and engineers are looking for the unknown mechanism related to the occurrence process, the effect of the damaged structures to its capacity and serviceability, and the intervention methods to control the rate of corrosion nowadays. One of the most prevalent liquid materials used in concrete is freshwater. However, the lack of freshwater for basic requirements in certain regions necessitates the adoption of an alternate material. Seawater, abundant in Indonesia, has the ability to substitute freshwater in concrete mixtures. However, its high concentration of chloride ions might raise the risk of corrosion in reinforced concrete structures. The laboratory experiment was proposed to find the empirical test result of the performance of corrosion prevention to the seawater mix RC structures. Three type of cements (PPC, PCC, and PPC-PCC mixture) were used as binder and two type of protection (steel coating and no coating) were applied in this research. One day after specimen casting, it were demolded and cured under water condition until 28 days. After that, the cylindrical and beams specimens were tested and the cubical specimens were exposed to three conditions (air-dry, wet, and dry-wet cycle) until a half-year and the half-cell potential test was conducted periodically every week. Based on the results, it demonstrated that the steel coating is the most suitable corrosion prevention method and PCC is recommended to maintain the corrosion potential stable to be passive.