Experimental Study On Mechanical Properties And Damping Properties Of Recycled Concrete Containing Bricks

The application of recycled concrete has better solved the problem of the way out of construction waste generated by the demolition of buildings,and has now become a new way to achieve sustainable development of resources and the environment.At present,most of the recycled coarse aggregates containing bricks for recycled concrete are obtained from construction waste(with waste concrete blocks and waste bricks as the main components)through unified recycling.In order to better solve the engineering application problem of brick-containing recycled coarse aggregate concrete,this paper uses brick-containing recycled coarse aggregate replacement rate,fly ash content and water-binder ratio as the research parameters to produce brick-containing recycled concrete.Based on the experiment,the influence of the above three parameters on the mechanical properties and damping properties of recycled concrete containing bricks was analyzed and studied.The main work and research results of the thesis are as follows:(1)The relevant indices of pure natural coarse aggregates and recycled coarse aggregates with bricks were studied,compared and analyzed.(2)Using the ABAQUS software to imitate and evaluate the recycled concrete specimens made of a single waste concrete recycled coarse aggregate and a single waste brick recycled coarse aggregate under uniaxial compression,and study the uniaxial compression,the basic failure characteristics of the two under uniaxial compression are studied.(3)The compressive strength test and split tensile strength test of recycled concrete specimens containing bricks,as well as the ultrasonic testing study of prisms under uniaxial compression were carried out.The effects of each research parameter on the compressive strength of recycled concrete containing bricks were analyzed.The influence law of strength,split tensile strength and ultrasonic wave velocity under compressive stress conditions.Based on the test results,the calculation formulas of axial compressive strength and split tensile strength based on the cubic compressive strength when considering the replacement rate of recycled coarse aggregate containing bricks were established,and the uniaxial compression damage degree of recycled concrete containing bricks was proposed.Calculation formula.(4)The stress-strain relationship of recycled concrete containing bricks was studied through uniaxial compression test of prism specimens,and the corresponding full curve equation was established.According to the related test results,based on the Weibull distribution and Lemaitre equivalent strain principle,the damage constitutive equation and damage evolution equation of recycled concrete containing bricks were established.(5)The free vibration attenuation method was used to study the damping performance of recycled concrete containing bricks through the free vibration test of the cantilever beam specimen.In the case of a certain water-binder ratio,from the comprehensive consideration of bearing capacity and energy consumption,specimen group B1 is the best choice;from the perspective of improving damping,specimen group B6 is the best choice.The regression equation of the damping ratio and ultrasonic wave velocity of recycled concrete considering the replacement rate of recycled coarse aggregate containing bricks is given.