Experimental Study On Impact Crushing Effect Of Granite Physical Properties And Mesostructure

With the development of the construction industry and the widespread use of concrete,natural sand is increasingly a shortage as a non-renewable resource.The emergence of machine-made sand has solved the problem of environmental problems due to shortage of natural sand and uneven development of buildings.The traditional industrial sand making industry often uses limestone as the mechanism sand mother rock,because the limestone is widely distributed,and the lithology basically meets the requirements of industrial sand.However,the characteristics of the mechanism sand with limestone as the parent rock do not fully meet the requirements of high performance concrete,and some high performance concrete also has certain requirements on the hardness and strength of the machine sand.Therefore,this topic attempts to replace limestone as the parent rock of the mechanism sand with highhardness granite,and conduct research on mechanism sand fracture from the properties of the parent rock itself.Studying the relationship between the physical parameters of the granite parent rock and the meso-structure to the crushing effect is of great significance for improving the production quality of the crusher.The subject uses indoor rock mechanics experiments,X-ray diffraction analysis experiments,scanning electron microscopy(SEM)experiments,and experimental data measured by single particle crushing experiments.Through theoretical analysis,the effects of physical properties and mesostructure of granite on impact crushing effect are studied,including the selection of fracture evaluation index,the relationship between granite physical property parameters and fracture effect,and the relationship between granite mesostructure and fracture effect.The relevant conclusions from the above studies are as follows:(1)The mineral composition and mechanical properties of the studied granite were tested by laboratory experiments on basic physical properties of rock and rock mechanics experiments.The main mineral composition of the granite is: quartz,potassium feldspar,plagioclase and mica.The mesostructure of granite was analyzed by SEM observation.It is concluded that the different mineral crystals have obvious differences under the mesostructure.The connection modes between different mineral crystals are also different.The image processing program of Matlab is used to collect the SEM.The microscopic structure of the image was quantitatively analyzed to extract the pore fracture damage characteristics in the mesostructure,which was used as a quantitative indicator to characterize the corresponding face ratio of different types of granite.(2)Through the single particle impact crushing experimental platform,the single particle crushing of granite was studied,and the crushing effect of different kinds of granite was obtained by the evaluation method of combined crushing effect.The results of the analysis of the mineral composition,mechanical parameters and mesostructure of granite combined with single particle impact fracture show that the mineral component has an effect on the fracture.The experimental results show that the increase of quartz content will reduce the degree of fracture,potassium feldspar.The increase in the content of plagioclase and mica will increase the degree of fracture;the higher the compressive strength and modulus of elasticity,the lower the degree of fracture.According to the mineralogical theory,the degree of cleavage of the four mineral crystals is different.The mesoscopic damage of different mineral crystals in the mesostructure and the contact between different mineral crystals are different,which can explain the degree of fragmentation of different mineral crystals in further detail.influences.The face rate in the mesostructure will reduce the crushing effect.(3)Quartz,plagioclase,modulus of elasticity and face rate have a certain effect on the shape of the broken grain.The influence of other parameters on the shape of the grain is not obvious.The work of this thesis is helpful to understand the fracture law of high-hardness parent rock in the mechanism sand.It has practical reference significance for selecting high-hardness rock as the mechanical sandstone in actual production.