Study On Mechanical Properties Of Corroded RC Continuous Beams Under Dual Repair System

In coastal environment,steel bars of reinforced concrete(RC)structures are easy to get corroded,which results in the reduction of ultimate load and durability of RC structures.In order to solve this problem,the impressed current cathodic protection technology(ICCP)to inhibit reinforcement corrosio n and the structural strengthening technology(SS)to improve the ultimate load of structures are proposed.Researches show that carbon fabric reinforced cementitious matrix(C-FRCM),which is composed of carbon fiber reinforced polymer(CFRP)and cementitious matrix,has both good electrical conductivity and strengthening performance.It can be used as the anode of ICCP system to inhibit steel bar corrosion,and as structural strengthening material to improve the ultimate load of structures.So we can use C-FRCM to establish ICCP-SS dual repair system to protect RC structures.In this paper,the mechanical properties of corroded RC continuous beams under dual repair system are studied by experiments,finite element analysis and theoretical analysis.The main contents are as follows:C-FRCM plates were used as the anode of ICCP system,and the effect of anode polarization on the material properties of C-FRCM plates was studied through chemical analysis,potential analysis and tensile tests.A total of 14 RC continuous beams were casted.Chloridion was added in advance and accelerated corrosion was used for 11 months to simulate the environment of Chloridion erosion.Through static tests,the failure modes,ultimate loads,load-deflection curves and ductility change of all continuous beams were obtained;and the effects of anode polarization degrees,CFRP layers and continuous complete wraps on the mechanical properties of continuous beams were studied.Beam models were established by Diana finite element analysis software.On the basis of verifying the correctness of the finite element models,the effects of corrosion rates,CFRP layers and continuous complete wraps on the ultimate loads of continuous beams were further studied through extended simulation.Combined with relevant design specifications,the flexual strengths of C-FRCM strengthened RC continuous beams were analyzed.Through the comparison among different design specifications,the modified calculations were obtained to calculate ultimate loads of C-FRCM strengthened RC continuous beams reasonably and safely.