Flexural performance of BFRP reinforced seawater sea-sand concrete beams with TRE SIP forms under a dry-wet environment

Abstract

In order to improve the serviceability performance and durability of basalt fiber-reinforced polymer (BFRP) reinforced seawater sea-sand concrete (SWSSC) beams in the marine environment, a composite of stay-in-place (SIP) form of textile-reinforced ECC (TRE) and BFRP reinforced seawater sea-sand concrete (BFRP-SWSSC) was designed, to enhance bearing capacity and deformation suppression ability of this composite structure in the marine environment. A total of 10 specimens with an effective span of 1500 mm and section size of 150 mm × 250 mm were designed in this experiment, including one BFRP-SWSSC beam and the rest composed of TRE composite as SIP forms. The effects of different dry-wet cycles, thicknesses of TRE SIP forms, shape of TRE SIP forms and production methods of TRE SIP forms on the bending performance of composite beams were studied. The specimens displayed as the TRE thickness increased, the failure mode changed from bending shear failure to balanced or compression failure. Whereas the bearing capacity of the specimens was indistinctively affected by 90∼270 dry-wet cycles. The deflection deformation and crack width of the beams were effectively improved by TRE SIP forms. Meanwhile the stiffness of composite beams was effectively improved by the chlorine salt dry-wet environment. With the effective bonding between TRE and SWSSC, the deflection and crack width of the composite beams were within specification limits. The eminent ductility of the composite beams was shown by the chlorine salt dry-wet environment, the ductility index of the specimen decreased with the dry-wet cycles increased from 90 to 270. Based on the section analysis method, a calculation method was proposed for the disabled bearing capacity of BFRP-SWSSC beams with U-shape TRE SIP forms in a normal environment. On this basis, the environmental impact factor of the salt dry-wet environment was suggested, and the experimental value is in commendable agreement with the theoretical value.