Study On The Influence Of Coarse Aggregate Size On The Impact Failure Characteristics Of Coral Concrete

In order to safeguard national sovereignty and security,China has developed and utilized the existing island and reef resources.In the process of construction,the search for an economical coral aggregate concrete has a far-reaching impact on island and reef construction.Through experiments,this paper explores the mechanical law and dynamic splitting mechanical properties of coarse aggregate size on the static compressive and tensile strength of coral concrete,analyzes the energy evolution law and failure morphology of coral concrete,and studies the crack propagation of coral concrete mixed with different particle size coarse aggregate by DIC technology.Firstly,using the RMT-150 experimental machine,combined with the knowledge of material mechanics,the physical parameters of coral concrete are obtained.The static compressive and tensile strength and failure characteristics of coral concrete are compared and analyzed.The experimental results show that the coral concrete which distinguishes the size of coarse aggregate has the characteristic of early strength.When the particle size of coarse aggregate is 5～10 mm,the compressive and tensile strength of coral concrete is the best.With the increase of coarse aggregate size,the compressive and tensile strength of coral concrete increases at first and then decreases.Secondly,the dynamic splitting experiments of continuous graded coarse aggregate with 5～16 mm and single graded coarse aggregate with 5～10 mm,10～16 mm,16～20 mm and 20～25 mm were carried out by using Φ75 mm device.The stress-strain relationship and failure characteristics of different coarse aggregate sizes and different strain rates are compared and analyzed.The experimental results show that the coral specimen has obvious strain rate effect and aggregate size effect in the stress-strain relationship of coral concrete.In the case of adding coarse aggregate with the same particle size,the dynamic splitting strength increases with the increase of strain rate;at the same strain rate,the dynamic tensile strength decreases gradually with the increase of coarse aggregate particle size.In the process of splitting,the broken state of coral specimen is two-half.with the increase of impact pressure,the deeper the breaking degree of coral concrete is,the more the number of fragments increases.When doped with the same particle size,DIF,incident energy and reflection energy all increase with the increase of strain rate,and they all have a good correlation.Finally,on the basis of SHPB experiments and DIC technology,the crack propagation of coral concrete with different coarse aggregate size during dynamic splitting experiment was analyzed,and the corresponding displacement field and strain field in Y direction are obtained.The experimental results show that when the size of coarse aggregate is the same,the displacement difference and strain of coral concrete increase with the increase of strain rate.At the same strain rate,the displacement difference and growth value of coral concrete increase gradually with the increase of the particle size of coarse aggregate.Figure 55 Table 12 Reference 83...