Study On The Dynamic Performance Of Steel Fiber Concrete Under Static Load

Steel fiber reinforced concrete(SFRC)is widely used in various types of engineering because of its good toughness,explosion and impact resistance.Steel fiber concrete components often bear static loads with dynamic loads,so it is particularly important to study the mechanics of steel fiber concrete under static dynamic conditions.In this paper,the hydraulic properties of static loads are studied for steel fiber concrete with volume doping of 0%,0.5%,1%,1.5%,2%and 2.5%,respectively.Through static cube pressure and pull test,the static mechanics of steel fiber concrete under various doping volumes are explored and their peak strength is compared.Compression and cleavage tensile impact tests using the split Hopkinson fracturing rod(SHPB)were used to study dynamic mechanics by analyzing stress-strain curves,combined with high-speed camera shooting,and DIC digital spot technology was used to study the expansion and destruction of steel fiber concrete cracks.The main work and conclusions of the paper are as follows:(1)Through the static test of the cube by SFRC of various volume doping,it is found that with the increase of steel fiber volume doping,the pressure strength of the cube is larger and smaller.The formulated plain concrete cubes are pressure-resistant and tensile-resistant at 80.7MPa and 4.5MPa,respectively.SFRC cubes have the greatest pressure strength at 0.5%volume doping,100.3Mpa,and 14.5%higher pressure strength compared to plain concrete.The tensile strength of the cube increased with the increase of the volume doping of steel fiber,and when the volume doping amount was 2.5%,the maximum tensile strength of the cube was 10.5MPa,which was 133%higher than that of plain concrete.(2)Using the split Hopkinson pressure rod(SHPB),the impact test of SFRC with different volume doping rates was carried out,and the dynamic compression and cleavage stretch stress-strain curve were obtained.With the increase of steel fiber volume doping,dynamic compression and tensile strength are increased and then decreased.When the volume doping of steel fiber is 0.5%,the dynamic compression strength is greatest,and when the volume doping of steel fiber is 1.5%,the dynamic cracking resistance strength is the greatest.With the increase of strain rate,SFRC shows obvious strain rate enhancement effect.(3)Through digital spot analysis,the displacement field and strain field of SFRC are obtained,and the results of displacement field and strain field analysis show that SFRC is from the beginning of uneven deformation to uniform deformation,and then to the whole specimen destruction process.With the increase of steel fiber doping,the increase of displacement and micro-strain decreases.The smaller the displacement and micro strain increase,the narrower the width of the specimen crack,the smaller the damage,and the better the integrity.A series of studies in this paper enrich the static dynamic mechanics test of steel fiber concrete,and contribute some reference value to the application of the separation Hopkinson press rod combined with DIC technology.Figure [Twenty-nine] Table [Ten] Reference [Fifty six]...