Abstract: Fibers enhance the psysical and mechanical properties of concrete and bring wider application of such composite in real projects. The technological development of equipment for the installation of concrete by spraying enabled the use of micro-reinforced concrete, primarily in constructive systems for ensuring the excavation of underground structures. The paper will present the results of testing physical and mechanical properties of concrete mixtures with steel fibers. Тhe adventages of using such a composite on lining of underground structures will be specified. Recommendations for making and installation of micro-reinforced concrete with spraying technology, as well as the approach to dimensioning the tunnel lining made of micro-reinforced concrete will be presented.
Keywords: fiber, concrete, physical-mechanical properties, spraying technologie