16 / 2022-03-06 22:39:45

Bond behavior of UHPC-based TRC plate under freeze-thaw cycles

Bond behavior,Crack bridging effect,Freeze-thaw cycles,Textile reinforced concrete (TRC),UHPC

In this study, an ultra-high performance concrete (UHPC) based textile-reinforced concrete (TRC) plate is proposed for hybrid strengthening of frost damaged concrete structures. The TRC plate is made of fiber reinforced polymer (FRP) grid and UHPC, which act as the reinforcement and matrix, respectively. In this new strengthening system, long and short fibers can improve the mechanical behavior of TRC plates due to the enhanced crack bridging effect. However, the bond properties of FRP grid and UHPC will deteriorate under freeze-thaw cycles (FTCs), which will affect the cooperative work, and thus decrease the reinforcement effect. To study the bond property degradation of TRC plates under FTCs, the bond behavior of fully saturated TRC plates under FTCs is examined. First of all, the crack bridging effect of hybrid fibers under FTCs is studied by carrying out the splitting and compressive tests on UHPC specimens.  Then the pull-out and axial tension tests on TRC plates are conducted, from which the interaction mechanism of hybrid fibers and FRP grid with cement-based matrix of UHPC will be investigated. Moreover, the effect of FTCs on bond property degradation of FRP-UHPC interface could be clarified. Finally, the damaging and enhancing mechanism of FTCs and the hybrid strengthening will be revealed respectively. The results will be significant to the development and design the new efficient and durable hybrid strengthening methodology.