Prospects of the use of high-tension fiber concrete as the basis for the formation of protective shelters and fortification structures during the russian-ukrainian war

This article analyzes the current state of protective shelters and fortification structures, foresees the modern possibilities of using fastening and basalt-type structures to increase the stability of concrete fortifications both during the construction of buildings for the protection of the civilian population, and for the creation of dugouts, fortifications and fire structures for the protection of personnel in accordance. Studies of the physical and mechanical properties of fiber concrete modified with plasticizers and active mineral additives using basalt and polypropylene fibers have shown that their introduction has a positive effect on the strength characteristics of concrete. The compressive strength of fiber concrete at day 28 increases from 61.4 to 77.0 and 96.2 MPa, respectively, and the flexural strength from 7.4 to 12.7 and 13.8 MPa, respectively. For the production of reinforced concrete protective materials, it is more effective to create hybrid high-strength concrete using fibers of different nature, followed by the formation of a reinforced concrete slab of the appropriate size. At the same time, the standard provides for the manufacture of prefabricated reinforced concrete elements of fortification structures and platoon support points of wall panels of the SP-1, SP-2 type and floor slabs PP-1 with a thickness of at least 300 mm from heavy concrete of strength class C32/40 with the use of plasticizers and active chemical additives. However, when using the obtained hybrid fiber concrete with strength class C50/60 and using a reinforcing mesh according to the calculated data, it is possible to reduce the effective thickness of the fiber concrete slab to 27.5 cm installation of fortification. The use of a reinforcing mesh in a complex with basalt fiber provides increased resistance of fiber concrete to the action of a high-speed impact due to an increase in the density of the cementing matrix as a result of a decrease in water consumption, as well as due to spatial three-dimensional reinforcement with dispersed basalt fiber. As a result of the mutual combination of the strength characteristics of the concrete matrix at the micro- and macro-levels in hybrid fiber concrete, it is possible to reduce the thickness of reinforced concrete elements and reduce the weight of the protective structure while meeting the requirements of the standards for such fortifications. An increase in the strength of cement stone occurs due to a decrease in the concentration of stresses in places of local stresses and a redistribution of energy throughout the volume of the material. The conducted studies of modern hybrid high-strength concrete with basalt fiber create new opportunities for the creation of protective concrete fortifications and fortification structures.