Flexural and Durability Performance of Seawater-Mixed Glass Fiber-Reinforced Polymer-Reinforced Concrete Slabs

Forty-eight simply supported glass fiber-reinforced polymer (GFRP) reinforced concrete (RC) slabs made with seawater-mixed concrete were tested to study potential performance degradation over different environmental conditions for 1, 6, 12, and 24 months. The environments consisted of typical field conditions of a subtropical region and immersion in seawater at 60[degrees]C (140[degrees]F) as an accelerated aging regimen. The GFRP-RC slab strips were 1828 mm (72 in.) long, 304 mm (12 in.) wide, and 152 mm (6 in.) deep and were reinforced with a 9.5 mm (0.375 in.) diameter GFRP bar. All the slabs were tested under three-point flexural loading and all exhibited bar rupture as the failure mode. The test results are reported in terms of the cracking load, ultimate moment capacity, and service-load deflections. Experimental results were compared to the analytical and ACI 440.1R-15 expected values. The type of concrete mixture design as well as the accelerated aging exposure seems to affect the ultimate capacity of GFRP-RC slabs. Analytical and ACI approaches reasonably predicted the experimental failure-moment capacity of most of the seawater-mixed GFRP-RC slabs, specifically for those exposed to field conditioning. The ACI 440.1R-15 equations were in good agreement with the experimentally measured deflections, where the largest deviations were observed for accelerated-aged specimens. Keywords: cracking load; deflection; durability; fiber-reinforced polymer (FRP); flexural capacity; reinforced concrete.