Flexural Strengthening of Large-Scale Damaged Reinforced Concrete Bridge Slab using UHPC Layer with Different Interface Techniques

This paper investigated the flexural behavior of large-scale damaged reinforced concrete (RC) bridge slab strengthened with the ultra-high performance concrete (UHPC) layer at the tensile side. The RC slabs were preloaded under flexure to introduce cracks. The pre-damage degree was evaluated using the crack width at the highest load. Then, two types of interface technique of the RC substrate were conducted before strengthening of the UHPC layer. The first technique was a combination of embedded studs and rough surface (S-R) on the RC substrate. The second technique was rough surface (R) only. Experimental results indicated that the UHPC layer enhanced the flexural capacity and stiffness of the damaged RC slab. The UHPC layer also restrained and delayed the crack development in the RC and UHPC layers. It should be highlighted that the strengthened slab with the S-R interface technique exhibited significant mechanical performance compared with the interface treated using the R technique only. Therefore, the enhanced flexural performance of the UHPC-RC slab using the S-R technique may have an impact on the analysis and design of strengthening large-scale damaged RC bridge slab