Research On Mechanical Properties Of C120 Machine-made Mountain Sand Concrete Super-high Pumping Pip

Due to the unique karst geology in Guizhou,machine-made mountain sand has become the main sand for concrete production in Guizhou.Because the mountain sand presents many angles and needles,it is necessary to produce machine-made sand through mechanized processing according to the requirements of concrete performance and compressive strength,so as to achieve adjustable and controllable.With the continuous development of urbanization,ultra-high pumping of ultrahigh strength concrete has become one of the important research directions of modern engineering.In order to ensure the successful completion of ultra-high pumping and avoid the phenomenon of concrete segregation plugging tube and tube bursting,this paper carries on the theoretical analysis of machine-made mountain sand concrete and pumping,analyzes the influencing factors of pumping pressure loss based on the orthogonal experimental design,and studies the pressure loss of ultra-high pump of C120 machine-made mountain sand concrete by in-situ stress-strain monitoring and numerical simulation.The main conclusions of this paper are as follows:(1)The flow and force of concrete in the pipeline are studied,and the stress of pump pipe and pumping pressure loss are studied and analyzed.Through orthogonal test design,the order of influencing factors of pump pressure loss is as follows: flow rate > ratio of radial pressure to axial pressure > slump > pipe diameter.(2)Relying on the project of Guiyang International Financial Center,the field test of C120 machine-made mountain sand concrete ultra-high pumping was carried out.Through the dynamic data acquisition system,the micro-strain of the pump tube at different heights is monitored in real time.It is concluded that the higher the height,the smaller the amplitude of the strain curve,and the average value of the ratio α of radial pressure to axial pressure of the pump tube is 1.67.(3)CFD method was used for numerical simulation of concrete ultra-high pumping,model verification was carried out,and then the simulation calculation of this test was carried out,and it was concluded that there was an approximate linear relationship between pumping pressure loss and viscosity flow rate respectively.And the pressure loss calculated under the Herschel-Bulkley model is about twice that of the Newtonian fluid model.