Experimental Study On Mechanical Properties Of Rockfill Concrete Based On An Actual Project

Rock-fill concrete has a broad application prospect in mass concrete engineering.However,due to the large particle size of rockfill aggregate,it is difficult to carry out mechanical tests of full-size specimens,which results in difficulties in obtaining mechanical indexes of rockfill concrete and limits its application in large and mediumsized engineering.In this paper,from the point of view of nondestructive testing,the ultrasonic springback test is carried out on large specimens of rockfill concrete,and the feasibility of using ultrasonic springback comprehensive method to test the compressive strength of rockfill concrete is studied.Based on mesoscopic level,will be seen as a concrete and the self-compacting concrete and the aggregate of two-phase composite materials,large concrete specimen obtained through mechanics test,pile of stone aggregates and mechanical index of the self-compacting concrete,combining the theory of compound material mechanics,the mechanical properties of concrete and the mechanical relationship between the mesoscopic composition,The reliability and universality of the relationship are analyzed by numerical simulation method,which provides a reference for the acquisition of mechanical indexes of rockfill concrete in engineering design.The main work and research results of this paper are as follows:1)The comprehensive ultrasonic rebound test of rockfill concrete is carried out,and the results show that the ultrasonic value and rebound value of rockfill concrete are positively correlated with the compressive strength of rockfill concrete.2)The national strength curve is not applicable to rockfill concrete;The curve of the relationship between the compressive strength of rockfill concrete and the ultrasonic value and the rebound value is fitted,and the error meets the requirements of the corresponding test regulations.3)The basic mechanical tests of large specimens of rockfill concrete have been completed.It can be seen that the rockfill aggregate has a significant strengthening effect on the strength and elastic modulus of self-compacting concrete.Before the specimen reaches the peak load,the stress-strain relationship of rockfill concrete under axial compression is basically a linear relationship.4)The results of composite material mechanics model prediction and numerical simulation show that the composite material mechanics model can be used to predict the compressive strength and macroscopic elastic modulus of rockfill concrete.This method has a certain reliability and can provide theoretical reference for engineering design.5)The mechanical test and numerical analysis of rockfill concrete show that the rockfill aggregate has the effect of hindering the crack development;The failure form of rockfill concrete under uniaxial compression shows an "X" shape,which is similar to that of ordinary concrete.