Durability Design Method Considering Reinforcement Corrosion due to Water Penetration

The current durability design for carbonation estimates that dry concrete experiences higher corrosion; however, in actual concrete structures, higher corrosion is observed in wet concrete. To solve this contradiction, a durability design method considering water penetration is proposed, in which the reinforcement is assumed to be corroded by contacting with water. The reinforcement corrosion depth is calculated as the accumulation of the stepwise corrosion. To calculate the number of annual contacts of water with the reinforcement, an equation to calculate the annual frequency of precipitation and a coefficient to take into account the effect of the water supply conditions are established. The comparison of the proposed method with an existing carbonation verification method indicates that the proposed method reflects the situation of an actual concrete structure more appropriately. The proposed durability design method was incorporated in the Standard Specifications for Concrete Structures of the Japan Society of Civil Engineers in 2017.