Experimental Study On High-strength Concrete Restrained By CFRP Sheet Under Axial Loading

Restricting concrete columns using fiber reinforced polymer (FRP) could makeconcrete material working at three-direction compressive status, thus its axial loadbearing capacity and ductility is improved. Concrete, as one kind most commonly usedcompressive construction materials, its axial compressive load bearing capacity closelyaffects structural members’ compression and bending mechanical properties. Presentresearch of FRP restrained compressive concrete mainly focused on concrete under C40strength level while there are less research on high-strength concrete. Concrete strengthlevel is a main influencing factor of FRP restrained concrete’s mechanical property whichis of great value researching under high-strength concrete strength level.A comparison test of carbon fiber reinforced polymer (CFRP) restrained cylinderconcrete column under axial load is managed. Five concrete strength levels vary fromC40to C60is chosen in this test. Two groups of cylinder specimen is made each strengthlevel. There are three specimens in one group, the results are averaged in each group. Atthe same time, multiple layers CFRP wrapped specimens of C40and C50concrete aremade, in order to research how CFRP layers could affect test result. It can be concludedfrom the test result that after CFRP reinforcement concrete’s compressive mechanicalproperties are considerably improved. Through Regression Analysis puts forward peakstress and peak strain models of CFRP restrained high strength concrete. And also it putsforward a stress-strain model.Calculated failure energy density of CFRP restrained concrete column using energymethod, analyzed the improvement of axial loading capacity after CFRP restrain throughenergy aspect. Through energy calculation of former FRP restrained concrete axial loadtest result studied different factors that influences specimen’s failure energy density.