| Reinforcement and concrete can work together,not only because they have a similar coefficient of linear expansion,but also because they have a good bond between them.For the study of the bonding properties of ordinary reinforced concrete,domestic and foreign scholars have done a lot of tests,got a series of results.Compared with ordinary concrete,light,high strength,good durability is the advantage of light aggregate concrete,which also determines the light aggregate concrete in the future development has a broad prospect.However,there is little research on the bonding properties of reinforced lightweight aggregate concrete,especially after the corrosion of steel bars,the research on the bonding properties between corroded steel and lightweight aggregate concrete is rarely reported.Therefore,the bonding performance between the corroded reinforcing bar and the lightweight aggregate concrete is studied in this paper.In order to study the bonding properties between lightweight aggregate concrete and corroded reinforcing bar,48 reinforced lightweight aggregate concrete specimens were prepared,which were divided into two groups: stirrup and no stirrup.Each group was divided into corrosion rate 0(no corrosion),the corrosion rate of 1%,the corrosion rate of 3%,the corrosion rate of 5% of the four conditions.In this paper,the corrosion of reinforcing bars is accelerated by electrochemical method in Jiangning laboratory,and the reinforcing bars in each batch are required to meet the requirements of corrosion.Before the test,the rebar was processed by pickling,drying and weighing,and the linear density of each reinforcing bar was measured.After the test,the test piece was subjected to broken treatment.The same was done by pickling,drying and weighing.Density,and finally the actual corrosion rate of reinforcing bars.After the corrosion of the reinforcing bars was accelerated,the test of each test piece was carried out.During the test,a displacement meter is fixed on the loading end and the free end respectively,and the relative slip value of the loading end and the free end is measured,and the load-slip curve of each specimen is obtained.During the test,the failure phenomena of each specimen were observed.It was found that the failure modes of the specimen were as follows: pull-out failure,splitting failure,pull-out splitting failure.Compared with ordinary reinforced concrete,the ultimate bonding strength of reinforced lightweight aggregate concrete is higher than that of ordinary reinforced concrete.The bond-slip curve of the specimen under different corrosion rates is analyzed.It is found that the effect of corrosion on the ultimate slip strength and ultimate slip strength of the non-stirrup specimen is relatively large.The influence of stirrups on the bonding properties of the test piece was analyzed.It was found that the same strength was higher than that of the non-stirrup test specimen under the same corrosion rate.Finally,the three-stage bond-slip formula of the specimen under different corrosion rate is proposed.Finally,the finite element software is used to simulate the drawing specimen.The Spring-2 unit is used to simulate the bond between the steel and the lightweight aggregate concrete.The Fs curve of the spring element is calculated by the fitting formula,and the load-slip curve under different corrosion rates is obtained.Compared with the experimental results,The fitting is more consistent and the correctness of the fitting formula is verified.At the same time,the influence of the factors such as the diameter of steel bar and the length of bond on the bonding performance of reinforced lightweight aggregate concrete was studied by using finite element software to expand the research sample.The results show that the diameter and bond length have a great influence on the ultimate bearing capacity of reinforced lightweight aggregate concrete,but the diameter of the reinforcing bar has little effect on the bond strength of the specimen.The bonding length can be improved in a certain range Bonding strength. |
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