FRP bars reinforced seawater sea-sand engineered cementitious composites beams with various salinities: Shear behaviors and cost effectiveness

To address the shortage of river sand and freshwater in the construction of the isolated islands, seawater sea-sand engineered cementitious composites (SS-ECC) has been developed and combined with fiber reinforced plastic/polymer (FRP) bars. Existing studies on SS-ECC have been mostly limited to using seawater with a world-average salinity. This study investigated the shear behaviors and cost effectiveness of basalt FRP (BFRP) bars reinforced SS-ECC beams with different seawater salinities. The stirrups were eliminated in these shear beams and digital image correlation (DIC) technique was performed. The shear behaviors of the SS-ECC beams were modelled by ABAQUS. The results demonstrated that SS-ECC beams reinforced by BFRP bars exhibited high shear capacity (i.e., a growth ratio of 167%-228%) and ductility index in comparison with the high strength mortar counterpart. Polyethylene (PE) fibers in the SS-ECC beams could provide a shear load contribution of 60%-70.01%. Maximum crack sliding and opening were less than 4 mm and 2 mm, which were much smaller than the length of PE fibers used in SS-ECC. Additionally, these SS-ECC beams owned satisfactory cost effectiveness. This research lays a foundation for the practical applications of the SS-ECC beams with different seawater salinities.