Flexural behavior of GFRP bars reinforced seawater sea sand concrete beams exposed to marine environment: Experimental and numerical study

Abstract

Experimental and numerical investigations were conducted on the flexural behavior of GFRP bars reinforced seawater sea sand concrete (GFRP-reinforced SWSSC) beams after exposed to marine environment. A total of eight beams were tested by using a four-point static loading facility. Variables included the exposure environment, the exposure duration, the water for mixing and curing, and the sea sand replacement ratio. The failure process and failure modes of the specimens were observed, the load versus deflection curves and the deflection versus maximum width crack curves were obtained. The effects of various parameters on the ultimate bearing capacity, initial stiffness, and ductility coefficient were analyzed. In addition, the finite element analysis (FEA) method was used to simulate the flexural behavior of GFRP-reinforced SWSSC beams, and the parametric analysis was then conducted to investigate the effect of reinforcement ratio and shear-to-span ratio on the flexural behavior of the beam. The test results show that, after 270 days of exposure, compared with the general atmospheric environment, the ultimate bearing capacity of the specimen is increased by 28.0 % after being exposed to salt-spray environment while decreased by 13.0 % after being exposed to tidal environment. During a 270-day exposure duration to tidal environment, with the increase of the exposure duration, the ultimate bearing capacity increases first and then decreases, while both the initial stiffness and ductility coefficient of specimens decrease. The use of seawater for mixing and curing is detrimental to the initial stiffness and ductility coefficient of the specimens. The increase in sea sand replacement ratio is detrimental to specimens' ultimate bearing capacity and initial stiffness. Besides, FEA results indicate that increasing the longitudinal reinforcement ratio can obviously improve the ultimate bearing capacity and the post-cracking stiffness of the specimen. Based on the current China, America, and Canada codes, the calculation method of the flexural capacity of GFRP-reinforced SWSSC beams exposed to marine environment is discussed and the prediction value of long-term ultimate bearing capacity is given.