The article presents the program and the results of experimental tests of beam samples with metal, basalt fiber reinforced polymer (BFRP) and hybrid (metal and BFRP) reinforcement. The samples were made of standard concrete with quartz sand as the fine aggregate and concrete with fine fraction wastes of a mining and beneficiation complex (MBC) used instead of the sand. Short-run tests of the beams under monotonous static loading until destruction enabled the conclusion that durability of the BFRP reinforced beams increased by 37-44% as compared to the metal reinforced beams. When hybrid reinforcing, reduction of the (BFRP) content did not produce an effect on decrease of durability indices; durability gains compared to the beams reinforced by metal made 38-41%. In the BFRP reinforced beams, due to the absence of plastic deformations in this reinforcement, there were no residual deformations after cessation of loading despite significant damage and deterioration of the concrete. Samples of beams made of concrete on fine fraction wastes of MBC, showed 1-8% higher strengths in comparison with similar beams made of concrete with quartz sand as the fine aggregate.

It is presented the study of the beam samples reinforced with metal armature, BFRP armature and beams with hybrid reinforcement using metal and BFRP armature. Half of the tested samples of beams were manufactured on concrete with river sand, as a fine aggregate. The others were made on concrete with fractionated fine wastes of Mining and Beneficiary complex (MBC) instead of the river sand. The tests were carried out by static loading of the scheme of a single-run free beam loaded in the thirds of gear. It was established that the beams reinforced with BFRP armature and the beams with hybrid reinforcement showed an increase of strength, about 40%, compared with the beams reinforced with metal reinforcement. The deflections of the beams reinforced with BFRP armature were 315% -331% higher than the deflections of the beams reinforced with metal reinforcement and 165% -205% higher than it is allowed by standards. The use of hybrid reinforcement allowed reducing their deflections in two times compared to the beams reinforced with BFRP armature. At a load level of 60% of the destructive, the deflections of beams with hybrid reinforcement BFRP and metal armature did not exceed the maximum permissible norm. When concrete samples manufactured, the substitution of the river sand with fine fractionated wastes from the Mining and Beneficiary complex (MBC) did not affect their durability and deformability (the difference between the values according to these indicators is within the statistical error).

The sustainable development of industry and society requires new approaches to the building structures design. The article presents the indices of strength, crack resistance and width of crack opening obtained as a result of experimental testing of beams with hybrid reinforcement with basalt plastic and metal armature. The following beams were examined for comparison purposes: the ferroconcrete beams of the control-series, and the twin beams reinforced only with basalt-plastic reinforcement. It was found that the replacement of the metal armature with basalt plastics led to an increase in strength, on average, by 40%. Similar strength indices were obtained for hybrid reinforcement beams. Crack resistance indices of hybrid reinforcement beams were found to be close to ferroconcrete beams of the control series. Crack resistance indices for these beams were also by 84... 89% higher in comparison with beams reinforced with basalt-plastics. The width of crack openings in hybrid reinforced beams did not exceed the maximum permissible norms at the operational level of loads (70% of destructive) and were smaller than in beams reinforced with basalt plastic reinforcement. Hybrid reinforcement efficiency has been established to improve the performance criteria of beams reinforced with composite armature.

The use of composite reinforcement in the structures subject to bending is limited due to their excessive deformation. One way to overcome this shortcoming is to use hybrid reinforcement where steel and composite reinforcement are used in combination. The effectiveness of this approach has been proven by previous studies. There are no studies on the establishment of the effective ratio between steel and composite elements. This paper presents the results of tests of prototype beams with hybrid reinforcement made of basalt fiber-reinforced polymer (BFRP) and steel. A total of 12 series of samples of beams, three beams in each series, were studied. The percentage of both types of reinforcement was variable; it varied from a ratio of 100% / 0% to 0% / 100% in increments of ~ 20% (the numerator of the fraction corresponds to the percentage of steel reinforcement, and the denominator – to the percentage of BFRP reinforcement). According to the results of tests of beams by static loading, it was found that the use of hybrid reinforcement allowed to increase the bearing capacity of the samples by 33% – 74%, depending on the percentage of reinforcement in the cross section, compared with the beams of the control series. Based on the nature of breaks and load-bearing capacity, the most optimal ratio of steel and BFRP reinforcement was 60% – 40%. The optimal percentage of cross section reinforcement is 1.07%.

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