Durability Evaluation of Headed Shear Studs Embedded in Ultrahigh-Performance Concrete via Electrochemical Corrosion

Corrosion is one of the most common sources of deterioration for steel girder bridges, especially in regions where deicing chemicals are frequently used. Over time, the end-bearing capacity of the girder is significantly reduced as the corrosion results in section loss of the web plate and flanges. A novel repair method utilizing ultrahigh-performance concrete (UHPC) has been proposed to restore the bearing strength of corroded girder ends. In this method, shear studs are welded to the intact area of the web plate near the bearing and embedded in a UHPC cast to create an alternative load path. As part of a multiyear research project, extensive experimental and analytical studies have proven the structural effectiveness of this repair. Yet, the durability of the repair needs to be investigated to gain confidence in its long-term performance. This article presents the results of push-out experiments performed on six specimens after subjecting them to accelerated electrochemical corrosion. The objective was to evaluate parameters relevant to the repair to investigate the effect of (a) the presence of chlorides before the repair is applied and (b) penetration of chlorides after losing the bond between the UHPC and web plate due to cyclic loading. In addition, the durability behavior of high-strength concrete (HSC) as the repair material was compared to UHPC. The results suggest that accelerated electrochemical corrosion induced onto a push-out sample did not reduce the mechanical performance of the headed studs during the limited time of exposure. These results were obtained for both UHPC and HSC. Although the electrochemical process accelerated the corrosion of the exposed steel material, it did not expedite or facilitate the penetration of ions into the concrete.