Basalt bars for concrete reinforcement called Basalt Fiber Reinforced Plastic (BFRP) is a new material, so it is necessary to identify the differences and limitations of their use in the concrete structures in relation to traditional steel reinforcement of concrete structures. The paper presents some chosen results of pilot research on the series of simply supported beams under flexure, reinforced with BFRP bars, compared to the reference beams with steel reinforcement. The tested beams were made of C30/37 concrete and reinforced with basalt bars with 8mm diameter having and tensile strength evaluated from the tensile tests. The analysis of the beam deflection and cracking behavior has been presented. The results show the different character of the load-deflection relationship of basalt reinforced beams compared to traditionally steel reinforced beams, as well as the significant influence of the type and quality of anchoring on the process of basalt bars tensile process

The use of sustainable materials is a challenging issue for the construction industry; thus, Fiber Reinforced Polymers (FRP) is of interest to civil and structural engineers for their lightweight and high-strength properties. The paper describes the results of tensile and shear strength testing of Basalt FRP (BFRP) and Hybrid FRP (HFRP) bars. The combination of carbon fibers and basalt fibers leads to a more cost-efficient alternative to Carbon FRP (CFRP) and a more sustainable alternative to BFRP. The bars were subjected to both tensile and shear strength testing in order to investigate their structural behavior and find a correlation between the results. The results of the tests done on BFRP and HFRP bars showed that the mechanical properties of BFRP bars were lower than for HFRP bars. The maximum tensile strength obtained for a BFRP bar with a diameter of 10 mm was equal to approximately 1150 MPa, whereas for HFRP bars with a diameter of 8 mm, it was higher, approximately 1280 MPa. Additionally, better results were obtained for HFRP bars during shear testing; the average maximum shear stress was equal to 214 MPa, which was approximately 22% higher than the average maximum shear stress obtained for BFRP bars. However, HFRP bars exhibited the lowest shear strain of 57% that of BFRP bars. This confirms the effectiveness of using HFRP bars as a replacement for less rigid BFRP bars. It is worth mentioning that after obtaining these results, shear testing can be performed instead of tensile testing for future studies, which is less complicated and takes less time to prepare than tensile testing.

A new type of HFRP hybrid bars (hybrid fiber reinforced polymer) was introduced to increase the rigidity of FRP reinforcement, which was a basic drawback of the FRP bars used so far. Compared to the BFRP (basalt fiber reinforced polymer) bars, modification has been introduced in HFRP bars consisting of swapping basalt fibers with carbon fibers. One of the most important mechanical properties of FRP bars is compressive strength, which determines the scope of reinforcement in compressed reinforced concrete elements (e.g., column). The compression properties of FRP bars are currently ignored in the standards (ACI, CSA). The article presents compression properties for HFRP bars based on the developed compression test method. Thirty HFRP bars were tested for comparison with previously tested BFRP bars. All bars had a nominal diameter of 8 mm and their nonanchored (free) length varied from 50 to 220 mm. Test results showed that the ultimate compressive strength of nonbuckled HFRP bars as a result of axial compression is about 46% of the ultimate strength. In addition, the modulus of elasticity under compression does not change significantly compared to the modulus of elasticity under tension. A linear correlation of buckling load strength was proposed depending on the free length of HFRP bars.

One of the most common causes of damage to concrete structures is the corrosion of the reinforcement. Reinforcement made from Fiber Reinforced Polymers (FRP) is considered as an attractive substitution of traditional steel reinforcement. A different technical characteristic of fiber reinforced polymer makes designing structures with FRP reinforcement differs from conventional reinforced concrete design. Therefore, it is necessary to identify the differences and limitations of their use in the concrete structures, taking into account their material and geometrical features. Basalt Fiber Reinforced Polymer (BFRP) is a relatively new material for reinforcing bars. On the basis of the ACI 440.1R-06 guidelines as well as experimental results for selected BFRP reinforced beams a model of compatibility in a system: BFRP bar - concrete was proposed. Additionally, based on the results of FEM simulations, the effect of BFRP bars ribbing on their adhesion to concrete was discussed.