Experimental Study On Influence Of Corrosion Rate On Bonding Properties Of Reinforced Concrete

This article explores the effects of corrosion-reinforced steel-concrete on the bonding performance through pull-out tests.The experiment studies 6 aspects and sets 28 kinds of working conditions.Then based on the experimental results,established a bond-slip constitutive relation for corroded reinforced concrete.The main conclusions of this paper are as follows:For non-corroded reinforced concrete:1.The larger the diameter of the steel bar,the smaller the bond stiffness,the ultimate bond strength decreases first and then increases,and the corresponding slip value increases.2.The higher the strength of the steel bars,the greater the bond stiffness and the greater the ultimate bond strength,the smaller the corresponding slip values.For corroded reinforced concrete:1.When the corrosion level is low(0.5%,1%),the bond stiffness increases with the diameter.When the corrosion level is high(2%-11%),the bond stiffness decreases with the diameter.2.When the corrosion level increases,the bond stiffness increases first and then decreases.For the smaller diameter HRB400 steel(d=14,d=20),the turning point is about 2%,and for the larger diameter HRB400 steel(d=25)and HRB500 steel(d=20),the turning point is about 1%.3.When the corrosion level increases,the ultimate bond strength first rises and then decreases,and when the steel diameter is larger or the strength level is lower,it increases or decreases faster.The maximum value is positively related to the diameter of the rebar.4.At the lower rust level,the ultimate bond strength reaches the maximum value,and the rust level at the maximum decreases with the increase of the rebar diameter.5.When the corrosion rate is close to 11%,the ultimate bond strength of reinforced concrete with d=14 and d=20 is still close to the non-corrosion state,but the reinforced concrete with d=25 decreases rapidly after the ultimate bond strength reaches the maximum value.6.When the corrosion level increases,the slip value at the ultimate bond stress decreases.7.When the corrosion rate is close to 2%,cracks appear on the specimen surface obviously,and with the increase of corrosion level the crack width was increased.8.As the crack width increases,the ultimate bond strength of HRB400 reinforced concrete decreases,but HRB500 reinforced concrete does not change significantly.9.The residual bond coefficient is positively correlated with the diameter of the steel bar and has no significant correlation with the strength of the steel bar.