Study On Mechanical And Interfacial Bonding Properties Of Dual Functional Strengthening Material

Carbon fiber reinforced cementitious matrix(C-FRCM)consisting of carbon fiber reinforced polymer(CFRP)bidirectional mesh and cementitious matrix can be used as strengthening material under the structural strengthening(SS)technology,and CFRP bidirectional mesh can be used as assisted anode material under impressed current cathodic protection(ICCP)technology.Using C-FRCM as dual functional strengthening material and establishing ICCP-SS dual functional system to repair reinforced concrete structures can not only prevent steel corrosion,but also restore or improve bearing capacity.In this paper,the mechanical and interfacial bonding properties of C-FRCM as dual-functional strengthening material are studied,and mainly include three parts: tests of electrifying and mechanical properties of C-FRCM,tests of C-FRCM interfacial bonding properties,as well as analysis and numerical study of C-FRCM interfacial bonding properties.In this paper,electrifying tests of C-FRCM composite plates under ICCP technology are carried out and the electric current density is 100 and 150 m A/m~2.The anodic polarization of CFRP bidirectional mesh increases with the increase of electric time and electric current density.The mechanical properties of C-FRCM under ICCP technology are studied by direct tension test and four-point bending test.The tensile and flexural bearing capacity of C-FRCM increase with the increase of CFRP bidirectional mesh layers and decrease with the increase of electric current density.The interfacial bonding properties of C-FRCM are studied by direct shear test and pull-out test.The weak interface of bond failure is the interface between CFRP bidirectional mesh and cementitious matrix.With the increase of bond length,the pull-out force increases,and the failure of CFRP bundles transits from pull-out slip to breaking failure.The static and fatigue properties of bonding interface decrease with the increase of electric current density.On the basis of pull-out test,the bond-slip mechanism of the bond interface between CFRP bundles and cementitious matrix,the basic formulae for calculating bond-slip and pull-out-slip calculations are analyzed to further understand the interfacial bonding properties of C-FRCM.Finally,the pull-out slip process is simulated by finite element analysis software ABAQUS.The validated finite element models are used for the analysis of the stress distribution of CFRP bundles,as well as the calculation and analysis of bond stress-slip constitutive model.