| In recent years,with the development of urbanization,the design and construction of high-rise buildings and spatial structures have become the mainstream demand.Useing of high-strength concrete and high-strength steel bars is beneficial to the construction of high-rise buildings and large-span structures.It can be save a lot of resources,reduce the weight of the structure bring convenience to construction hoisting.The good adhesion between steel bar and concrete ensures the safety and reliability of the structure.However,steel corrosion has always been a major problem affecting the adhesion of reinforced concrete.Corrosion not only causes the change of the mechanical properties of the steel bar,but also cause the longitudinal cracking of the concrete cover,thus affecting the durability of the reinforced concrete structure.In this paper,the cdhesion about HRB600 high strength steel bar and high strength concrete is studied by experiment and finite element analysis.Through the central pull test of 87 on test-piece that the shape is the prism object.A series of studies were mainly conducted on the bonding and anchoring problem between corroded HRB600 high-strength steel bar and high-strength concrete,and the corrosion rate of HRB600 high-strength reinforced concrete was studied Influence,and the change of concrete strength,protective layer thickness,coupling rate,anchor length and other factors on the bond strength and bond slip curve between HRB600 steel bar and high-strength concrete under stable corrosion rate.Finally,the finite element modeling analysis of the central drawing specimen with stirrups is carried out,and the influence of the corrosion rate on the bond-slip curve of high-strength reinforced concrete is analyzed by finite element software and compared with the test results.According to the experimental and finite element analysis results,the following conclusions are mainly drawn:(1)There are three final failure states in this test,namely concrete splitting failure,steel bar pulling out failure and steel bar pulling out failure.(2)Corrosion makes the bonding strength of HRB600 rebar and C80 high-strength concrete specimens increase first and then decrease.(3)The critical rust rate of the group without stirrups was 3.68%,and that of the group with stirrups was 4.11%.This is because stirrups can inhibit the development of rust expansion cracks and reduce the critical rust rate.(4)Under the condition of stable corrosion rate,HRB600 rebar and concrete specimens have a positive linear correlation with the improvement of concrete strength,the thickness ofprotection layer and the increase of hoop ratio.With the increase of bond anchorage length,the relative bond anchorage strength has a negative linear correlation.(5)The corrosion of stirrup has a great influence on the bonding performance of high-strength reinforced concrete.With the increase of hoop ratio,the bond strength of specimens with rusting stirrup decreases gradually.(6)According to the test results,the average limit bonding strength formula for stabilized corroded high-strength reinforced concrete is obtained by introducing the coefficient of stable corrosion,the correction coefficient of protection layer and the correction coefficient of anchorage length.(7)According to the test value,the bond-slip constitutive relation suitable for corroding HRB600 steel bar and C80 concrete is proposed,which USES the test value to correct the characteristic value of the constitutive relation,and also corrects the bond stress and slip value under different corrosion rates.The value of bond slip simulated by this formula is closer to the actual value. |
PDF Full Text Request