Study On Flexural Behavior Of Continuously Hooked Steel Fiber Reinforced Concrete With Two Grade Aggregate

Steel fiber reinforced concrete with two-graded aggregate has such advantages as reducing the cement content,reducing the adiabatic temperature rise,reducing the dry shrinkage,improving the mechanical properties of concrete,good wear resistance and durability,and so on,which is widely used in hydraulic concrete structure.With the progress of steel fiber processing technique and technology,the strengthening and toughening effect on concrete can be achieved by improving the macroshape of steel fiber,among which the new continuously hooked steel fiber has a better effect.In order to study the influence of the new continuously hooked steel fibers on the strength,toughness and crack resistance of concrete,this paper studied the influences of volume fraction from 0 to 1.5% and type include 1 and 2 of hooked steel fiber on the properties and flexural properties of concrete with two grading of aggregate.The main content is as follow:Through the cube specimens with size of 150mm×150mm×150mm compressive and splitting tensile experiment,the effects of volume fraction and type of hooked steel fiber on compressive strength and splitting tensile strength of concrete with two grading of aggregate were investigated.The experimental results indicate that there is no obvious correlation between the compressive strength of SFRC and the volume ratio of steel fiber.The compressive strength of SFRC increases with the number of hooks increasing.The volume fraction and type of hooked steel fiber have a significant effect on the splitting tensile strength.Through the prism specimens with size of 150mm×150mm×550mm four-point bending experiments,the influence of volume ratio fraction and type of hooked steel fiber on flexural strength and flexural toughness of concrete with two grading of aggregate were researched.The experimental results show that the flexural strength and flexural toughness of SFRC increase as steel fiber volume ratio increases.The effect of the type of hooked steel fiber is concrete to flexural strength and flexural toughness of SFRC.The fiber distribution was analyzed by means of the image processing technology,and the influence of the type of hook on the distribution of steel fiber was studied.The experimental results suggest that fiber content in bean cross-section decreases with the increase of the number of hooks..Flexural toughness is closely with total fiber number,fiber distance and fiber content.The fiber distribution in bean cross-section was analyzed with fractal theory,and the relationship between fractal dimension and flexural properties was studied.The experimental results suggest that the fiber distribution in bean cross-section has significant fractal significance.The fractal dimension increases as steel fiber volume ratio increases.Flexural strength and flexural toughness increase with the increasing of fractal dimension.The flexural toughness which take the fractal dimension was proposed.