Corrosion Characterisation Of Reinforced Concrete Structures Exposed To Marine Environment

Abstract

One of the principal agents responsible for the degradation of reinforced concrete structures is the corrosion of the reinforcing rebar. In this study, the effects of chloride penetration as well as other degradation phenomenon on reinforced concrete structures in marine environment are being investigated. Field investigation was carried out using 2500mm×50mm×50mmreinforced concrete columns, produced from concrete grade 40 and 20 respectively. Three major tests, including half-cell potential, chloride content and carbonation depth were carried out at three different zones on the reinforced concrete columns corresponding to the atmospheric zone, tidal zone and submerged zone (zones A, B and C). Consequently, it was found that for both specimens, higher values of half-cell potentials, greater than .35V CSE were recorded in between 8-9 points in the submerged zones (corresponding to the lower tidal zone), while chloride ion content in the respective zones ranges between 0.17-0.28 with the highest values corresponding to the lower tidal zones. On the other hand, specimen A shows no evidence of carbonation while specimen B shows evidence of carbonation of up to 5mm in the lower tidal zone. Based on the findings, it is clear that the lower tidal zone has significant effect on corrosion and also has higher chloride content in comparison with other zones.