Bond behavior of geopolymer concrete with steel and GFRP bars

In the last years geopolymer concrete (GPC) has shown great potential for use in structural elements. In this context, it has become fundamental to investigate on the bond behavior of this new concrete matrix with reinforcing bars. Data found in literature showed that GPC performs better than ordinary Portland cement (OPC) concrete in terms of bonding with deformed steel bars. In addition, few authors have focused in the study of the bond stress-slip behavior between GPC and glass fiber-reinforced polymer (GFRP) rebars. In this paper the bond -slip behavior of GPC with both steel and GFRP reinforcing bars will be investigated by means of pull-out test with centered bar setup also considering the effect of the bond length. The main results showed that little difference in bond-slip behavior occur between the two different steel bar diameters used. On the other hand, sand-coated GFRP bars showed lower bond capacity in respect to deformed steel bars. Finally, an increase in ultimate bond load has been observed when the bond length was increased.