Reinforced Concrete Degradation in the Harsh Climates of the Arabian Gulf: Field Study on 30-to-50-Year-Old Structures
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This paper presents the results of a field study carried out on three reinforced concrete (RC) structures built in the 1960s, 1970s, and 1980s to determine the main load (environmental) and the resistance (for example, the concrete quality and clear cover) factors affecting the durability of the infrastructure in the harsh environmental conditions of the Arabian Gulf region. The effects of degradation, such as the carbonation depths and chloride concentration profiles, in the columns, beams and slabs were determined from concrete core samples. To determine the durability factors, the concrete resistivity to electrical charge, the rapid chloride permeability, and the sorpitivity were measured. Digital image processing was performed to estimate the cement contents and the proportions of other ingredients used in the concrete samples. In most of the structural members, the chloride threshold for steel depassivation had been surpassed and the carbonation had reached the steel surface. The spalling of the concrete cover was observed with severe corrosion damage to the reinforcing bars. It is expected that this study will help understand the degradation phenomena in RC structures in the Gulf region and similar hot, humid, and saline environments. The results will help to establish the input parameters for the chloride diffusion and carbonation models in aggressive environmental conditions. Because the concrete quality directly impacts the initiation of many deterioration processes such as corrosion of the steel reinforcement and carbonation, the results could be used to predict the remaining service life of existing RC structures with similar concrete properties.