Experimental Study Of Concrete’s Mechanical Properties And Early Shrinkage Mixed With Super-fine Sand Produced In The Yellow River

Currently, the resources of construction sand are increasingly scarce in our country, meanwhile there is a phenomenon of excessive exploitation of super fine sand in the middle and lower reaches of the Yellow River. In order to provide a theoretical basis for the application of Yellow River super fine sand in the construction market, the author studied and analyzed the mechanical properties and early shrinkage of concrete prepared by using the Yellow River super fine sand in this paper.In this paper, we selected the Yellow River super fine sand and artificial mechanism sand produced in Zhengzhou as raw material, and tested the related material properties, and obtained some physical properties of the fine sand in the Yellow River. Then the mix radio of C40 and C30 grade concrete was determined by testing the strength of concrete prepared in advance, and then we replaced artificial mechanism sand with 0%, 15%, 30%, 45% of the Yellow River super fine sand as the fine aggregate to produce the concrete test block. There was an analysis of the effects of age, curing conditions, super fine sand dosage on the compressive strength through the cube compressive strength test of Yellow River super fine sand concrete test block, and through the regression analysis of test data, super fine sand content on the compressive strength of cubes influence coefficient formula were obtained, meanwhile the fitting degree was good. Through the splitting tensile strength test, the influence of the age and the super fine sand content on the splitting tensile strength was analyzed, and the relationship between the splitting tensile strength and the cube compressive strength was obtained through regression analysis. Through the static elastic modulus test, the influence of the super fine sand content in the Yellow River on the static elastic modulus was analyzed, and the relationship between the static elastic modulus and compressive strength was obtained by regression analysis. Through the experimental analysis, it was found that the mechanical properties of concrete are better when the Yellow River super fine sand content is 15% and 30%.In this paper, the influence of age, super fine sand content on shrinkage of concrete at early age performance was analyzed through the inchoate shrinkage properties of C30 and C40 grade concrete test about 0%, 15%, 30%, 45% of the Yellow River super fine sand mixed with volume groups, and according to the existing research data, the concrete early age shrinkage rate prediction model which was related to the age and the super fine sand content was established, and compared the predictive value obtained by the model and the experimental value, it was found that the coefficient of variation was small and had a good correlation. Through the experimental analysis, it was found that the effect of the early shrinkage of concrete is best when the amount of super fine sand in the Yellow River is 15%.