Flexural Performance of HFRP-RC Composite T-Beams with Different Interfaces

Abstract

A method of improving the capacity of reinforced concrete T-beams using profiles made of hybrid basalt-carbon fiber sheet–reinforced polymer (HFRP) bonded to concrete using three different methods was researched. Various basalt-carbon ratios were considered, along with three types of different bonding interfaces. The flexural performance of the HFRP-RC (reinforced concrete) composite T-beams with different interfaces was studied by both experimental and theoretical analysis methods, the main areas of focus including the feasibility of the interface type, failure mode of these beams, load capacity, flexural stiffness, and ductility, among others. Three types of interface were studied by both the double-lap shear test and the four-point bending test of beam specimens. Good bond behavior can be achieved with the three methods and the additional anchorage system. The hybrid effect of hybrid fiber sheets made of basalt fiber (BFRP) and carbon fiber (CFRP) was studied both by a tensile test of hybrid fiber sheets and by a four-point bending test. A constitutive relationship of hybrid fiber sheets was put forward in which an improvement factor of the CFRP ultimate strain value was introduced according to the result of the material and checked by the beam test results. Meanwhile, the HFRP-RC beams were found to have an obvious postyield stiffness, which can control the structure deformation after the yield of steel bars. The postyield stiffness formula for the HFRP-RC beams is given, and its precision was checked by using both the test results and the literature results. Finally, the ductility of these beams was studied and results show that these kinds of beams can have adequate energy ductility.