## 5 Discussion  
A comparison of the results was conducted with the data from the study of the mechanical and strength properties of the lightweight pumice concrete reinforced with basalt fiber (BPLC) containing nano-ground calcium carbonate (GCC) [2]. GCC was used as a standard substitute for Portland cement in the amounts of 5%, 10%, 15%, 20%, and 25%-, and 6-mm long basalt fibers were added in two grades of 0.5% and 1% by volume. Experimental results showed that at an early age, the mixture with GCC had lower mechanical strength results; however, it was comparable in strength to the reference mixes at a later age. The addition of GCC also decreased water absorption, sorption capacity, and showed an increase in magnesium sulfate resistance compared to the reference lightweight concrete. The use of basalt fiber improved the mechanical properties of BPLC, but the inclusion of the fiber reduced the properties of the fresh concrete. However, in [2], porous substitutes for coarse aggregate made of dense rocks, which create a frame and provide the bearing capacity of concrete, have not been studied. The research work that [5] presents is an experimental study of the mechanical behavior of structural expanded clay concrete from basalt fiber. The main purpose of this study [5] was to check the effect of crushed basalt fiber in expanded clay concrete to increase its strength, that is, its absolute characteristics. However, [5] did not study the relative physical and mechanical characteristics, in particular, it did not determine the coefficient of constructive quality, that is, the most important characteristic for and lightweight concrete. The aspects noted above are widely disclosed and highlighted by us in this study. As a result of the analysis of Figures 13 and 14, the following was established: Based on the obtained deformation diagrams, the peak with displacement up and to the left of the diagram is presented in the deformation of LFRC on a combined aggregate. On the other hand, the remaining diagrams of the control concrete compositions had a lower peak with a shift to the right. Thus, based on the analysis of the data obtained on the deformation of the tested sample, it can be concluded that the recommended composition and technological methods for controlling the strength and deformative characteristics of LFRC on a combined aggregate are advisable. According to the results of experimental studies on the influence of the volumetric content of fiberglass and the method of its distribution in the preparation of a fiber-reinforced  
Figure 14: Diagram of the state of tensioned concrete (S4—control composition of concrete; LFCCA—LFRC on a combined aggregate). concrete mixture on the strength and deformation characteristics of LFRC on a combined aggregate, the most effective combination of these factors was determined. AS such, with the inclusion of basalt fiber at 2% of the volume of the concrete mixture where the fiber distribution was conducted according to the 2t method (preliminary mixing of cement, sand, crushed stone + mixing with fiber + mixing with water), the best values of the strength and deformation characteristics of LFRC are observed in the combined filler. Thus, in comparison to the values obtained when testing the control samples, the increase in compressive strength was 12%, the value of the prismatic strength increased by 25%, the tensile bending strength increased by 34%, and the axial tensile strength increased by 11%. The ultimate deformations during axial compression decreased by 10%, decreased by 12% during axial compression tests, and the modulus of elasticity increased by 11%. Cement consumption remained unchanged. CCQ of LFRC on a combined aggregate is 35.3 \(\times\) 10\({}^{-3}\) MPa \(\times\) m\({}^{3}\)/kg. This concrete is the most effective in terms of construction since in comparison to traditional heavy concrete, it has a sufficiently high strength at a lower density value.