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The paper describes the recent developments of Hybrid Fibre-Reinforced Polymer (HFRP) and nano-Hybrid Fibre-Reinforced Polymer (nHFRP) bars. Hybridization of less expensive basalt fibres with carbon fibres leads to more sustainable alternative to Basalt-FRP (BFRP) bars and more economically-efficient alternative to Carbon-FRP (CFRP) bars. The New-Developed HFRP bars were subjected to tensile axial loading to investigate its structural behaviour. The effect of hybridization on tensile properties of HFRP bars was verified experimentally by comparing the results of tensile test of HFRP bars with non-hybrid BFRP bars. It is worth to mention that the difference in obtained strength characteristics between analytical and numerical considerations was very small, however the obtained results were much higher than results obtained experimentally. Authors suggested that lower results obtained experimentally can be explained by imperfect interphase development and therefore attempted to improve the chemical cohesion between constituents by adding nanosilica particles to matrix consistency.

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.

The main factors determining the choice of fiber-reinforced polymer (FRP) materials are the intended use of the designed structure and the environmental conditions in which it will be located. Currently, the FRP-based materials have a variety of applications in the construction industry, from the secondary structural elements of buildings, to a complicated designs, where the only FRPs were used. The advances in FRP technology have spurred interest in introducing innovative hybrid fiber-reinforced polymer (HFRP), which potentially can be used as reinforcing/enhancing material. This paper describes the investigation on newly-developed hybrid fiber-reinforced polymer HFRP bars, which were created by modification of basalt fiber-reinforced polymer BFRP bars in terms of physical substituting of the certain amount of basalt fibers by the part of carbon fibers. Modification is aimed at achieving of better properties in obtained material and simultaneously ensuring cost-effectiveness concept. The investigation includes the preparation and numerical considerations on HFRP bars as well as first attempts of experimental structural testing of innovative HFRP bars.