Mechanical properties of FRP such as strength and stiffness as well as the bonding interface between FRP and concrete will be badly deteriorated when exposed to high temperature. Furthermore, the effect of thickness of insulation with different type of concrete strength has not yet been studied elsewhere in numerical studies. Therefore, this study is to assess the thermal-structural behaviour of insulated FRP strengthened RC beam exposed to elevated temperature using ABAQUS. The proposed numerical model of 200 ×300 mm RC beam subjected to 2 hours standard fire curve (ISO 834) had been validated with the analytical solution. The validated numerical model then is used in parametric study to investigate the behaviour of fire damaged normal strength concrete (40 MPa) and high strength concrete (60 MPa) of RC beam strengthened with CFRP using various fire insulation thickness of 12.5 mm, 25 mm and 40 mm, respectively. The result of steel characteristic strength reduction factor is compared with analytical using 500˚C Isotherm methods. The parametric studies indicated that the fire insulation layer is essential to provide fire protection to the CFRP strengthened RC beams when exposed to elevated temperature. The insulation layer thickness of 25 mm had been found to be the optimum thickness to be used as it is able to meet the criteria of temperature distribution and displacement requirement. In conclusion, the numerical model developed using ABAQUS in this study is to carry out assessment on the thermal-structural behaviour of the insulated CFRP-strengthened RC beams at elevated temperature.

Recently, new materials have been developed in the field of bridge design, one of which is FRP composite. To investigate this topic, the Polish National Centre for Research and Development has founded a research project, whose objectives are to develop, manufacture and test a typical FRP bridge superstructures. Two innovative ideas of FRP composite girder-deck structural systems for small and medium span bridges have been proposed. This paper describes the demonstrative bridges and presents the research results on their development and deployment. The finite element analysis and design procedure, structural evaluation in the laboratory and some results of the proof tests carried out on both bridge systems have been briefly presented.

Over the past decades, using of sustainable materials in construction is a challenging issue, thus Fibre Reinforced Polymers (FRP) took the attention of civil and structural engineers for its lightweight and high-strength properties. The paper describes the results of the shear strength testing of three different types of bars: (i) basalt- FRP (BFRP), (ii) hybrid FRP with carbon and basalt fibres (HFRP) and (iii) nano-hybrid FRP (nHFRP), with modification of the epoxy matrix of the bar. The hybridization of carbon and basalt fibres lead to more costefficient alternative than Carbon FRP (CFRP) bars and more sustainable alternative than Basalt FRP (BFRP) bars. The BFRP, HFRP and nHFRP bars with different diameters ranging from Ø4 to Ø18 mm were subjected to shear strength testing in order to investigate mechanical properties and the destruction mechanism of the bars. Obtained results display a slight downward trend as the bar diameter increase, which is the most noticeable for HFRP bars. In most of the cases, BFRP bars were characterized by greater shear deformation and less shear strength compared to HFRP and nHFRP bars. Performed testing may contribute to comprehensive understanding of the mechanical behavior of those types of FRP bars.

The widespread use of Fibre-Reinforced Polymers (FRP) reinforced concrete (RC) structural members is hindered by their low fire resistant characteristics, limiting their use to cases, where fire resistance is not a priority. Presented and discussed are experimental results pertaining to the flexural members subjected to heating and simultaneous loading. Solely non-metallic FRP bars: (i) Basalt FRP (BFRP), (ii) Hybrid FRP (HFRP) with carbon and basalt fibres and (ii) nano-Hybrid FRP (nHFRP) with modified epoxy resin, were used as internal reinforcement for beams. The destruction of the beams was caused in different ways, beams reinforced with BFRP bars were destroyed by reinforcement failure while those reinforced with hybrid FRP bars were destroyed by concrete crushing. The BFRP reinforced beams obtained a maximum temperature, measured directly on the bars, of 917 °C, compared to beams reinforced with hybrid FRP bars, where the temperature on the bars reached 400-550 °C at failure. Moreover, the highest registered ductility was obtained for BFRP reinforced beams as well, where the maximum deflections reached approximately 16 cm.

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.