Maintenance modeling and cost assessment for repaired reinforced concrete structures exposed to chloride attack in coastal areas in Vietnam

One of the primary causes that can reduce the lifespan of concrete structures is chloride-induced corrosion of reinforcing steel. Recent research has shown that material properties, exposure conditions and climatic conditions have a significant influence on the structural deterioration of reinforced concrete (RC) structures, especially in marine environments. The objective of this paper is to predict the durability of RC structures damaged by chloride-induced corrosion in near-shore environments in Vietnam, considering regular repair activities. A two-dimensional model of chloride penetration in square cross-section RC columns repaired by cover replacement techniques is studied. Two repair methods with different shapes (orthogonal and circular) are considered. The effects of the different repair methods on the life span of structures are investigated in case studies in Vietnam that consider the variations of annual temperature and humidity in three coastal areas such as Danang, Haiphong, and Ho Chi Minh City. Finally, maintenance and repair costs during the lifetime of structures are calculated for each case. The study suggests that for RC structures exposed to two-dimensional chloride ingress, the most critical areas for assessing chloride concentration, predicting corrosion initiation, and planning repair schedules are the corners of the columns. In addition, the chloride-induced corrosion process is strongly influenced by the local weather conditions, especially in areas with high humidity. The repair method with circular concrete replacement seems to be more efficient in terms of maintenance schedule and cost than the repair method with orthogonal concrete replacement.