Experimental Study On Shear Resistance And Bonding Properties With Steel Bars Of Brick-rich Recycled Concrete

The application of recycled concrete has solved the problem of the dependence of civil engineering construction on natural aggregates and the environmental pollution of construction waste,such as land occupation and discharge.This paper mainly studies the shear resistance of brick-rich recycled concrete and its bond-slip performance with steel bars.The main work and achievements of the thesis are:(1)The basic physical properties of the brick-rich recycled coarse aggregate were tested and analyzed.And through a number of trials,the good ratios are numbered ZRC-A,ZRC-B,ZRC-C and ZRC-D.(2)For the HRB600,HRB400 and HPB300 steel bars,the tensile strength,elongation and other experimental studies have obtained the basic mechanical properties.(3)Four different types of equal-width widened short-short beams were poured and analyzed for shear performance.The test results show that in terms of shear deformation,the performance characteristics of brick-rich recycled concrete is similar to ordinary concrete.The shear curve equation of the brick-recycled concrete beam is given,and the shear modulus calculation formula of the brick-rich recycled concrete is also proposed.(4)48 cube-drawn specimens with dimensions of 150 mm × 150 mm × 150 mm and 36 prism-drawn specimens of 150 mm × 150 mm × 250 mm were cast in four mix ratios,and different types of steel bars were embedded in the axis.After 28 days of maintenance,the center pull test and the ultrasonic test damage test were performed.The test results show that the larger the strength value of the recycled concrete,the larger the load value corresponding to the unit slip value and the steeper the load-slip curve,no matter what kind of test piece and the bonding performance of the ribbed steel bar is better than that of the light round steel bar.(5)The mechanism of ultrasonic testing of concrete damage is used,and the relationship between damage degree and sound time is given from the perspective of damage mechanics and the damage test of ultrasonic testing concrete is designed.The test results show that as the test progresses,the degree of damage is getting bigger and bigger.Comparing the test pieces under the four ratios,the change of the damagedegree is not too obvious.According to the experimental data,a bond-slip constitutive model between recycled concrete and steel bars considering damage parameters is proposed.(6)Combining the above-mentioned bond slip test data and the obtained constitutive relation,a simple numerical simulation was carried out using Abaqus.The simulation results show that the numerical simulation results of the prismatic members are in good agreement with the experimental results.