Study On The Frost Durability Of Reinforced Concrete Under The Degree Of Corrosion

Because of the effect of climate and temperature,the reinforced concrete structures in northern cold area will suffer from the damage of freezing.Finally,freeze-thaw damage will occur,which will cause a great influence on the safety and stability of the structure.In addition,the reinforced concrete structure will rust in humid climate,it also has great influence on structural safety and stability.Therefore,this paper adopts the combination of laboratory experiment and numerical simulation,choosing three groups of reinforced concrete specimens with different corrosion rates,focuses on the study of the change of antifreeze and bond properties of reinforced concrete,which is under the freeze-thaw cycles and corrosion effect.The research content and the main conclusions are as follows:(1)The internal stress wave velocity of reinforced concrete subjected to different freeze-thaw cycles and different corrosion rates were tested by impact echo method.The study found that for the same set of specimens,with the increase of the number of freeze-thaw cycles,reinforced concrete specimens with low corrosion rate have higher wave velocities,at the same time the decrease is slow and the frost resistance is good.When the corrosion rate increases further,the wave velocity of the test block decreases more and the frost resistance is worse.(2)The specimens' bond performance and the change rule of the tensile load-displacement curve under different freeze-thaw cycles and different corrosion rate are studied by drawing experiment.The results show that,as the influence times of freezing-thawing cycle become larger,its bond performance becomes worse.The smaller the tensile capacity amplitude is,the smaller the relative slip displacement is.For the test blocks with same times of freeze-thaw,when the test blocks have a small corrosion rate,which bond performance is better than that of the uncorroded test block.It's tensile strength amplitude will also increased.When the corrosion rate of the specimens was further increased,the bond performance will also deteriorated,in addition,the tensile strength of the tensile strength will also be decreased.The ductility of the test block becomes worse.(3)For the same rust rate test block,the relationship between the stress wave propagation velocity and the tensile strength subjected to different freeze-thaw cycles was studied.The data were fitted by exponential function.The result shows that the tensile strength of reinforced concrete subjected to freeze-thaw damage has a good correlation with the internal stress wave transfer velocity,and is subject to exponential and power function relations.(4)According to the experimental data,we can simulate the drawing experiment of the reinforced concrete with ABAQUS which under the effects of different grades of concrete strength ?the diameter of steel and the corrosion rate.It is found that when the strength grade of concrete is increased or the diameter of reinforcement is increased,the Mises equivalent stress of the test block will increase and its bond performance will be improved.In addition,when the corrosion rate of reinforcement increases,the Mises equivalent stress of the test block first increases and then decreases,and the bond performance changes accordingly.