Correction factor suggestion for ACI development length provisions based on flexural testing of RC slabs with various levels of corroded reinforcing bars

Reinforcement corrosion is a major influencing factor in deterioration of reinforced- and prestressed-concrete structures. Concrete structures exposed to chlorides from seawater, deicing chemicals, salt, salt water, brackish water, or spray from these sources are more vulnerable to corrosion. The corrosion characteristics of corroded reinforcing bars are a very important topic in the durability and strength of concrete structures. Both experimental and analytical studies on this topic, however, are scarce to the point of nonexistence. In order to qualitatively and quantitatively understand the effect of corrosion level on the bond strength and development length in RC slab members, a series of tests are carried out. The reinforcing bar of the specimen is corroded after concrete casting. One type of reinforcing bar HD10 is corroded to 1%, 2%, 3%, 5%, 7%, 10%, and 15% of its original cross-sectional area of the reinforcement using current-induced accelerated corrosion technique. After the effective corrosion is applied, flexural tests are performed. The analysis results show that the effect of corrosion level on bond strength and development length was apparent. In addition, after 2% corrosion level, the current design code for development length should be reviewed and more studies are needed in the future for verification.