EXPERIMENTAL RESEARCH ON THE FLEXURAL BEHAVIOR OF FRP REINFORCED ECC-CONCRETE COMPOSITE BEAMS STRENGTHENED WITH CARBON FIBER SHEET

Three groups of flexural members strengthened with different layers of carbon fiber sheet (CFS) were designed and manufactured, and their static flexural test were carried out, one group is fiber remforce popupner (FRP) reinforced concrete beam, one group is FRP reinforced engineereed cementitious composite (ECC) beam, and one group is FRP reinforced ECC-concrete composite beam. The effects of the number of layers of CFS on the ultimate load, failure mode, crack and deformation of strengthened ECC-concrete composite beams were studied. The results showed that under the same load, the deformation and crack width of the composite specimens and ECC specimens were smaller than those of the concrete specimens. ECC layered in the tension zone of the flexural members could effectively improve the capatity to resist deformation and cracks. The cracking load and ultimate load of the specimens strengthened by the CFS were higher than those of unstrengthened specimens. The ultimate load of the composite beam strengthened by one, two and three layers CFS were 12.5%, 16.6% and 19.7%, respectively, higher than that of unstrengthened beam. CFS could effectively improve the bearing capacity and capacity to resist deformation and cracks. The improvement effect increasesd with the increasing of number of CFS layers, but the increasing rate gradually decreased.