Document Type : Research Paper
Authors
1
Associate Professor, University of Hormozgan, Faculty of Engineering, Bandar Abbas, Iran
2
Master Student, Civil Engineering, Islamic Azad University, Bandar Abbas Branch, Iran.
10.22124/jcr.2025.30673.1701
Abstract
Reinforced concrete structures in marine environments, particularly along the Persian Gulf coasts, are susceptible to gradual deterioration caused by chloride ion penetration and carbonation. The hot and humid climate, high evaporation rates, direct seawater splash, and industrial pollutants create a highly aggressive environment for these structures. The present study aims to investigate the field performance and microstructural vulnerability of reinforced concrete wharves through a case study of the Bandar Abbas ports. To comprehensively analyze the degradation mechanisms, several tests were conducted on both field-extracted and laboratory-prepared specimens, including chloride ion penetration profiling, scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), and compressive strength testing. The results indicate that chloride ion ingress is the primary factor responsible for the premature deterioration of marine structures in the Persian Gulf. These ions contribute to the formation of unstable compounds such as Friedel's salt and weaken the C-S-H gel/nanostructure, directly leading to increased porosity, reduced microstructural integrity, and loss of mechanical strength. SEM images and EDX elemental analyses revealed high concentrations of chloride ions, microcracks, and damage to the interfacial transition zone (ITZ) between the cement paste and aggregates. Chloride penetration profiles showed ion concentrations exceeding the critical corrosion threshold at depths greater than 100 mm, indicating deficiencies in mix design, compaction, and curing practices. Moreover, the results demonstrated that natural coverings such as marine shells and increased concrete cover thickness significantly reduce chloride ingress and play an effective protective role.
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