Plain Concrete Prisms Externally Strengthened by CFRP Bonded with Graphene Oxide-Modified Magnesium Phosphate Cement

摘要

Graphene oxide (GO)-modified magnesium phosphate cement (MPC) is used as an adhesive to bond carbon fiber-reinforced polymer (CFRP) composites in the formation of MPC-CFRP strengthening materials. The performance of GO-modified MPC paste and the mechanical performance of MPC-CFRP-strengthened concrete prisms are investigated in this paper. Workability and mechanical properties of MPC with different dosages of GO (0.035 wt% and 0.07 wt% by MgO) are tested. The results indicate that GO has negative effects on the fluidity and setting time of MPC. Mechanical properties of MPC are improved by a proper addition of GO. Compared with unstrengthened prisms, bearing capacity and stiffness of strengthened concrete prisms increase with the layers of MPC-CFRP: maximum bearing capacity increased by 372.08%, and stiffness increased by 130.15%, respectively. MPC with the optimal mechanical properties (MPC-GOl) is used as the adhesive to bond CFRP, which forms a new type of strengthening composite and greatly improves the bearing capacity and ductility of plain concrete prisms.