Research On The Relationship Between Dynamic Elastic Modulus And Compressive Strength Of Concrete

In the north cold area of our country,the freeze-thaw damage is an important form of concrete structure damage.On one hand,the current method to test the concrete freeze-thaw damage index is mainly the concrete dynamic elastic modulus.On the other hand,compressive strength of concrete is a comprehensive measurement of the concrete performance,and it reflects the internal characteristics of concrete,so there should be a correlation between the concrete compressive strength and the dynamic modulus of elasticity.In this paper,a series of tests were carried out on the concrete compressive strength and the dynamic modulus,and later the difference of ultrasonic velocity of concrete under different freeze-thaw times were analyzed.The research analyzed the relationship between the indicators of concrete.The major findings are as follows:(1)Analysis on the four different groups of resistance and durability of the concrete frost.From the perspective of the mass loss rate and relative dynamic elastic modulus,the results show that when the concrete grade is higher,the specimen quality loss is smaller,and the relative dynamic elastic modulus decreased more slowly.Besides,when the concrete grade is higher,the frost resistance of concrete is better,especially the high strength concrete specimen C60,which performs obviously.(2)According to the analysis of the compressive strength and frozen thaw cycles of four groups of concrete,the results shows that with the increased times of the freeze-thaw cycles,four groups of concrete specimen ultrasonic velocity decreased slowly,and the compressive strength of the cube is also reduced.In the same time of the cycles,when the concrete strength grade is higher,the ultrasonic in the specimen spread is faster.(3)if the damage variable is tested according to the freeze thawing and the relative dynamic modulus of elasticity,the results present that in the same time of the freeze-thaw cycles,when the grade of concrete is higher,its freeze-thaw damage degree is lower,which shows that the freezing thawing make a relatively low damage on its internal part.The damage degree of freeze-thaw growth of concrete specimens C60 is slower than the above three groups.So it means that high strength concrete can resist freeze-thaw damage better than ordinary concrete.(4)Based on the relative dynamic elastic modulus,the compressive strength,and the ultrasonic velocity changes respectively,the two order polynomial function of concrete freeze-thaw damage attenuation model is established.The major findings are the two order polynomial function model of three variables can well reflect the changes of the internal structure of concrete freeze-thaw process.(5)After analyzing the correlation between ultrasonic velocity and compressive strength,the results show that ultrasonic velocity and relative dynamic elastic modulus can better express the concrete values of compressive strength test before and after.Therelative data of ultrasonic velocity and compressive strength is 0.6674,and the relative data of relative dynamic and compressive strength is0.6944,so the value of compressive strength of relative dynamic elastic modulus has higher accuracy.