Third International Conference on Advances in Civil, Structural and Construction Engineering - CSCE 2015
Author(s) : AR.DRAKAKAKI, CH.APOSTOLOPOULOS, K.KOULOURIS
During the last decades, many durability problems have been recorded on reinforced concrete (RC) structures, which are located in coastal areas. Chloride corrosion is among the various degradation mechanisms of steel reinforcement which lead to the premature deterioration of RC structures. In this paper, an effort was carried out to increase the corrosion resistance of high ductility dual-phase steel (B500c), without any interference in the chemical composition or in the production mode, but through shot peening process. More specifically, shot peening treatment was used on the one hand in order to clean the surfaces of the steel bars and to remove the “impurities” that act as underlying destructive cores on them, and on the other hand, in order to create surface compressive stresses. The whole process was carried out according to the pertinent protocols, with the use of olivine pellets. Subsequently, the corrosion resistance behavior of the steel was experimentally examined, both with and without shot peening process. The specimens were inserted in a laboratory salt-spray exposure chamber, in accordance to the ASTM B117-94 specification (directly exposed to the corrosive medium), for different periods, under 8 cycles wet/dry per day. The two specimens groups (with and without shot peening) were subjected to tensile tests. The first results were very encouraging, as shot peened specimens recorded lower pit depths and lower mass loss percentages improving, in this way, their corrosion resistance. At the same time, these specimens showed higher mechanical performance in comparison to the common ones. The first positive results of the shot peening process triggered the continuation of the present paper through further investigation.