Compressive and tensile strength of steel fibrous reinforced concrete under explosive loading

摘要

In order to determine the compressive and tensile strength of concrete under conditions of explosive loading, and to develop a methodological framework in this regard, three types of concrete have been investigated: concrete with fine-grained granite in the form of crushed stone having a static compressive strength of 47MPa, the same concrete with the addition of steel fibers and also the same concrete reinforced by steel bars. The samples were rods of 50 and 100mm diameter and five to ten diameters in length. The compressive fracture occurs at a relatively small distance of propagation of the load pulse along the rod and is accompanied by fast decay. The measurements of parameters of the compression pulse at the end of the fracture zone allowed us to determine the values of the dynamic compressive strength of the concrete while measurements of the free-surface velocity history at long distances were used for determining the dynamic tensile strength or spall strength values. The values of the dynamic compressive strength were found to be 2.5 times higher than the static strength. The steel fibers increased the dynamic compressive strength by about 10%. The obtained values of the dynamic tensile strength are 3-8 times higher than the values of the static tensile strength. The steel fibers increase the tensile strength by 20-50%. The reinforced sample has shown an increase of dynamic tensile strength by a factor of about 30.