Behavior of bond-slip relationship of lightweight and normal weight geopolymer with various FRP sheets using end-groove anchorage

In this study, the effect of using an end-groove anchorage system (EGA) on the bond-slip behavior between fiberreinforced polymer (FRP) sheets and both normal weight geopolymer (NWG) and lightweight geopolymer (LWG) concrete was investigated by considering the effects of different types of FRP sheets (CFRP, BFRP, and GFRP), FRP bonding lengths of 50 and 100 mm, FRP bonding widths of 50 and 75 mm, and with and without an EGA system. A total of 96 specimens of NWG and LWG concrete were cast, bonded with FRP sheetsand tested under double-shear tension. The results of employing EGA revealed that the bond-slip behavior of NWG specimens differed from that of LWG specimens. Using the EGA system significantly enhanced the bond force by an average of 16 % and 18 % for NWG and LWG, respectively. However, the ultimate slippage of NWG specimens was reduced by as high as 60 % as a result of using the EGA system, but it contributed to increasing the ultimate slippage remarkably by as high as 73 % for LWG concrete specimens. It's worth noting that the bond-slip behavior of CFRP sheet outperformed all other types of FRP sheets for both NWG and LWG concrete. The type of geopolymer concrete, the kind of FRP sheets, and the EGA process all influence specimen failure modes. The EGA system was more favorable for the bond failure of CFRP sheet and NWG concrete specimens, resulting in the avoidance of sudden debonding of CFRP composite and block contacts. A bond-slip model was proposed in this study to predict specimen bond force and slippage. The model was well fitted to the experimental data and appeared to have potential as a practical application which is the first and only model in the literature in this field.