Experimental Flexural Behavior of Concrete Bridge Slabs, Externally Reinforced with CFRP

Abstract

The flexural behavior of bridge concrete slab sections that were subjected to a level of cracking and were later repaired with carbon fiber reinforced polymers (CFRP) was evaluated in order to study the possibility of using this type of strengthening in existent bridge slabs in Costa Rica.
Three concrete slabs were built: the first was a control specimen (which was not strengthened with CFRP) and the two others were meant to evaluate the effect of CFRP strengthening. The loading scheme consisted in placing the slabs on three simple supports and applying two concentrated loads, in order to generate positive and negative moment regions. The slabs meant for strengthening were initially loaded with an 80% of their ultimate strength with the purpose of generating cracks that needed repairing. The cracks whose crack widths exceeded 0.3 mm were repaired by epoxy injection and then the two slabs were strengthened with CFRP in the positive and negative moment regions. Finally the three specimens were loaded until failure.
The slabs reinforced with CFRP were 36% stronger than the control slab, which suggests that this type of strengthening can be used in existing bridge slabs in the country. Additionally, the experimental results obtained in this project were compared with the experimental results from the project of Carranza (2017) and both projects had similar results, with difference percentages varying between 10% and 14%.