Experimental Study On Strength And Durability Of Superfine Sand Concrete In The Yellow River

The development and utilization of the yellow river ultra-fine sand has been paid more and more attention by the engineering field.Especially in recent years,the rapid expansion of urban areas and urban village reconstruction plan,resulting in a sharp increase in the amount of concrete,natural medium-coarse sand is facing the risk of resource depletion,more stimulated the research and application of the yellow river ultra-fine sand concrete.However,because of the wide distribution of ultra-fine sand,the performance of ultra-fine sand is not the same in each region,so it can not be generalized.the research goal of this paper is the ultra-fine sand of the yellow river.The ultra-fine sand is taken from the yellow river beach in the northern part of Zhengzhou city.after years of deposition,a large number of sand dunes are deposited on the bank of the river.the fineness modulus of the sand is 0.6 ~ 0.65,which belongs to the ultra-fine sand.Yellow river ultra-fine sand reserves,stable quality,low price,used to partially replace the coarse sand in the preparation of concrete,not only can alleviate the shortage of coarse sand in the current situation,and the concrete industry and commercial concrete station also have good economic benefits.In this thesis,the workability,compressive strength,flexural strength,splitting tensile strength,modulus of elasticity,impermeability and frost resistance of concrete with five strength grades of C20,C30,C40,c50 and C60 are studied experimentally.the mechanical properties and durability of the concrete are discussed in order to provide technical support for the application of yellow river ultra-fine sand in engineering.Experimental studies have shown that:(1)The artificial mechanism of sand mixed with a certain amount of yellow river ultra-fine sand,the preparation of ultra-fine sand concrete workability can meet the requirements of commercial concrete pumping.(2)The yellow river ultra-fine sand and machine-made sand are mixed into mixed sand concrete,which improves the fine aggregate particle size distribution and improves the compressive strength,flexural strength and splitting tensile strength of the concrete;Adding ultra-fine sand can improve the compactness of concrete,reduce the internal pores of concrete and enhance the impermeability and frost resistance of concrete.(3)The mechanical properties and durability of the yellow river ultra-fine sand concrete can meet the engineering requirements.