SHEAR BEHAVIOR OF RC BEAMS STRENGTHENED WITH TEXTILE REINFORCED GEOPOLYMER MORTAR

To investigate the feasibility of using textile reinforced geopolymer mortar (TRGM) to strengthen concrete members, the bond strength of geopolymer mortar with carbon fiber textile was tested at ambient temperature and after exposure to elevated temperatures, through double shear tests. Then static load tests were conducted on RC beams shear strengthened with different layers of TRGM (1 layer, 2 layers and 3 layers). Also, one unstrengthened beam, and one shear strengthened beam with textile using epoxy resin as adhesive, were tested for comparison. Test results show that the bond strength of geopolymer mortar with carbon fiber textile at ambient temperature reached 2.02 MPa, and that no significant strength degradation occurred at a temperature not higher than 300℃. Compared to the unstrengthened beam, the shear bearing capacity of the RC beam strengthened by a single layer of TRGM, without special anchorage measures, is increased by 47.1%. This increasing extent is about one half of that of the beam strengthened with textile using epoxy resin as adhesive. The highest strengthening effectiveness is achieved in the beam strengthened by two layers of TRGM, in which the tensile strength of fibers was fully utilized. Finally, a simplified model for calculating shear bearing capacity of TRGM strengthened RC beams is proposed, and the calculated results using this model agree well with the test results.