Corrosion Damage Diagnosis of a 44-Year-Old Ammonium Nitrate Prill Tower in a Petrochemical Complex

Abstract

One of the most aggressive environments for concrete is in an industrial area such as a petrochemical complex compound. In this area, exposure to highly corrosive materials such as ammonium nitrate, high carbonation rates (resulting from increased concentration of carbon dioxide (CO2) in industrial environments, and environmental conditions (such as relative humidity and temperature fluctuations) can collectively contribute to weakening the durability of concrete. This paper presents a study of corrosion damage of concrete and the embedded reinforcing steel of a 44-year-old nitrate prill tower of a petrochemical complex located in Shiraz, a city in southern Iran. After a thorough visual inspection and observing different deterioration mechanisms, a comprehensive set of conventional experiments to assess the durability of reinforced concrete was performed. Various degrees of deterioration were associated with different exposure conditions along the tower. Results indicated that the concrete had been severely decalcified up to 3 cm from its surface. However, reinforcement corrosion was negligible. Results moreover show that exposure to ammonium nitrate solutions was the primary reason for the high deterioration of the concrete of the tower.