Design Of Concrete Rheometer And Experimental Study Of Rheological Properties

With the rapid development of concrete technology,the workability of concrete in engineering construction is getting higher and higher.The workability of concrete directly affects the processes of pumping and pouring during the construction process.Concrete that meets workability requirements can not only reduce the work intensity of workers during construction,but also save construction costs.However,in the current practical engineering application,the way of judging the workability of concrete is too simple,mainly relying on the slump tube to test the slump of concrete,but under certain conditions,the slump cannot fully reflect the workability of concrete,which will cause a series of Failure,such as concrete blocking during pumping.In order to solve this problem in engineering practice,working parameters that comprehensively reflect the fluidity of concrete will be needed,and related research at home and abroad has proved that the rheological properties of concrete can better reflect the workability of concrete,so this article expands on the rheological properties of concrete After conducting research,a rotary concrete rheometer was designed and developed and related experimental research was carried out.This paper analyzes the detection principle of concrete rheometer,and designs the overall scheme of concrete rheometer.The concrete rheometer mainly uses the torque sensor to measure the torque value of the mixing blade at different speeds to calculate the rheological parameters of the concrete,and the torque sensor belongs to a more precise measuring instrument.Therefore,it is necessary to ensure the torque sensor in the structural design of the concrete rheometer measurement accuracy.In addition,the output shaft of the torque sensor and the clamping rod in the concrete rheometer are connected by a coupling.In order to avoid the additional force on the clamping rod affecting the measurement results of the torque sensor,this design optimizes the fixing method of the clamping rod.And because the torque sensor is bolted to the support frame,this assembly method will affect the accuracy of the torque measurement.Therefore,this paper studies and analyzes the processing error and stress deformation of the support frame,and gives a reasonable assembly method of the torque sensor.In terms of automatic control,the principle of automatic measurement of rheological parameters is introduced.The hardware circuit,PLC and host computer program are designed to realize the automatic measurement of rheological parameters of concrete rheometer.The test research is mainly divided into three parts,including the feasibility test of rheological parameter measurement,laboratory concrete rheological property test and mixing station rheological property test.The feasibility test results show that the reproducibility of concrete rheological parameter measurement is good,which proves that the torque detection unit inside the servo motor can replace the torque sensor.Laboratory tests mainly study the effect of cement slurry content,different gradations,and vibration mixing methods on the fluidity of concrete and the relationship between concrete slump and rheological parameters under these influencing factors.The test results show that as the cement slurry content in the concrete increases,the concrete slump increases and the yield stress decreases,which proves that the concrete slump and the yield stress are linearly related;the effect of different grades on the slump of fresh concrete is more Small,but the yield stress of concrete decreases with the decrease of the aggregate content of large particles in the gradation;the test results of different mixing methods show that the vibration mixing can improve the slump of the concrete and reduce the concrete yield stress and vibration compared with the ordinary mixing The effect of mixing on plastic viscosity is related to the content of cement slurry in concrete.When the content of cement slurry is small,vibration mixing can reduce the plastic viscosity of concrete.When the content of cement slurry in concrete reaches a certain level,vibration mixing will increase the plastic viscosity of concrete.The test of the mixing station is mainly based on the concrete produced on site,measuring and analyzing the relationship between the slump and the rheological parameters,and finally verifying that the concrete rheological parameters can reflect the workability of the concrete in the actual project.