| At present,in my country,the construction waste generated by building demolition has brought considerable pressure to the ecological environment.At the same time,my country’s strict environmental protection policies have also led to a serious shortage of a large number of stone resources required for the production of concrete materials for urban and rural construction and civil engineering.The production of recycled aggregate from construction waste is currently one of the most important sources of aggregate for the production of concrete materials for civil engineering.pollution problem.However,the performance of recycled aggregates is the main obstacle limiting the promotion and application of concrete.At present,research on recycled concrete mainly examines recycled concrete that uses recycled aggregates instead of natural aggregates,uses coarse aggregates,and uses recycled products partially or completely.it.Little research has been done on the mechanical properties of steel and its effect on joint properties.This thesis mainly studies the basic mechanical properties of recycled concrete,the bonding properties of deformed steel bars and recycled concrete and its acoustic emission characteristics,which provides a reference for the application of recycled aggregate in concrete.The main research contents and main conclusions are as follows:(1)Measure the main physical properties of recycled aggregate and test raw materials,determine the test mix ratio through trial mix,and study the influence of test variables on compressive the anti-knock performance and elastic modulus of recycled concrete.(2)The elastic modulus test was performed using ultrasonic flaw detection,the functional relationship between the replacement rate of recycled fine aggregate and the dynamic and static modulus of elasticity of the produced recycled concrete was studied,and the Poisson’s ratio of the recycled concrete was studied.(3)138 deformed rebar-recycled concrete center extraction specimens with a side length of 150 mm were designed and fabricated,and the failure form and failure process and characteristics of the center extracted specimens were analyzed and studied through the drawing test,and τ-s curves under different parameter variables were obtained.(4)Using the acoustic emission monitoring technology to monitor the test methods of steel bars and recycled concrete samples in time,and study the acoustic emission coefficient.The results show that the stronger the binding strength,the stronger the AE result.The calculation of the AE b value gives the difference between the AE b value and the amount of reinforcing paper.(5)A deformed contact was formed between the deformed steel bars and the recycled concrete.Based on the acoustic emission test results,the relationship between the joint failure of the deformed steel bars and recycled concrete and the acoustic emission parameters were revealed.A measure of bond failure development between steel and recycled concrete was established. |
