STUDY OF THE PERFORMANCE OF FIBER CONCRETE IN STRUCTURES UNDER DYNAMIC INFLUENCES

The greatest effectiveness of fiber concrete is achieved with the correct combination of the properties of its individual components. The properties of fiber concrete as a composite material largely depend on the type and type of fiber used in its composition, which determines its overall characteristics. 
For cost reasons, steel fiber is quite effective, since the modulus of elasticity is several times higher than the modulus of elasticity of concrete, and with sufficient anchoring in the concrete matrix, its strength can be fully used, which will significantly improve the performance of the composite at the stages of and after the formation of cracks. 
One of the important characteristics of fiber concrete in relation to dynamic influences is its impact strength, which largely depends on the type of fibers used, its shape, type, and length. An important factor for the perception of impact and other dynamic influences is also the amount of applied fibers in the concrete matrix mixture. 
Scientists [3,4,15,16,17] over the years have established that at a concentration of metal reinforcing fibers up to 2%, it does not cause their comming and provides a composite with better properties. 
The fiber can have different types of cross section - round, oval, rectangular and others, with dimensions from 0.2 mm to 1.6 mm and length from 5 mm to 160 mm. Tensile strength - 400-1100 MPa. 
The effectiveness of the use of steel fiber concrete is achieved as a result of reducing labor costs, primarily due to the partial or complete exclusion of reinforcement works and a decrease in the material capacity of structures, as well as a decrease in their cost with a simultaneous increase in the operational qualities and durability of structures. 
To get a better idea of the influence of the number, type of reinforcing metal fibers and their characteristics on the perception of impact strength, the experimental studies described below were performed.