Impact of sulfate damage on the behavior of full-scale concrete bridge deck slabs reinforced with FRP bars

This paper is aimed to analyze the performance of reinforced-with-FRP, sulfate-damaged concrete bridge deck slabs under concentrated loads, using the nonlinear finite element analysis (NLFEA) method. For experimentation purposes, twenty-seven full-scale models have been prepared to simulate concrete bridge deck slabs, with a length of 3000 mm and a width of 2500 mm. The parameters of the study were: (i) type of reinforcement, as three types were tested: glass FRP (GFRP), carbon FRP (CFRP), and steel; (ii) bottom transverse reinforcement ratio (ρ = 0.38, 0.46, and 0.57); and (iii) sulfate damage level, which consisted of three levels: Level 0 (undamaged), level 1 (73 days), and level 2 (123 days). All of the slabs models were equipped with two parallel girders of steel as supporters. To be able to analyze the models' performance up till failure, the load exerted by sustained truck wheels (87.5 kN CL-625 truck) was simulated by subjecting each slab model to a monotonic single concentrated load, with a contact area of 600 × 250 mm, at the center of the models. The simulated models encountered a punching shear mode of failure. The analysis showed that the models that were strengthened with CFRP and GFRP bars exhibited a remarkable improvement in the models': ultimate load, elastic stiffness, post-cracking stiffness, elastic energy absorption, and post-cracking energy; whereas, there was less influence on the models' ultimate deflection, compared to the ones strengthened with steel.