23

Sep

Basalt FRP research

Research:

” A mechanical and environmental assessment and comparison of
basalt fibre reinforced polymer (BFRP) rebar and steel rebar in
concrete beams” by
Marianne Inmana
Eythor Rafn Thorhallssonb
Kamal Azraguea

Another type of non ferrous fibre that has gained popularity in the last two decades is basalt fibre. Various manufacturers have employed this fibre because of its low cost, high ecological compatibility during the production process, and functional properties . The density of basalt (2600 kg/m3) is approximately one third of the density of steel (7680kg/m3), which means Basalt FRP is a lighter, stronger construction material compared to steel. It is expected that these mechanical properties will have implications on the environmental performance of BFRP as a construction material. Furthermore, it is easier and cheaper to produce basalt fibres, compared to other fibre types such as glass fibre. A previous study estimates the energy required for basalt fibre production to be around 5 kWh/kg in an electric furnace, whilst the energy required to produce steel is around 14 kWh/kg [13]. It is expected that this disparity in energy consumption will have an impact on the environmental performance of Basalt FRP. BFRP reinforcement bars are therefore a promising material in concrete as a replacement for steel reinforcement bars.

Basalt rock is principally composed of silica, alumina, with lime, magnesium oxide and ferric oxide found in lesser percentages . For fabrication of continuous basalt fibre (CBF), the quantity of each material needs to be controlled . Mineralogically speaking, basalt is primarily constituted of the minerals plagioclase, pyroxene and olivene . To create basalt fibre, the basalt rock is mined and crushed into basalt fractures. Batches of basalt fractures are sorted and mixed in order to achieve the desired composition. These blended fractures are then melted in a furnace. Once the basalt fractures are heated to an optimal temperature of between 1400 -1600°C, the molten basalt is extruded into continuous filaments with a diameter of 12-18µm . CBF may be formed into chopped basalt fibre strands, basalt fabrics, basalt wires or meshes, which can then be used in a wide range of application areas .
In order to convert the fibres into Basalt FRP tendons, the CBF is glued together with resin. In some cases, sand is gluedto the BFRP rebar surface to give a higher level of cohesion between the Basalt FRP rebar and concrete. The total proportion of resin varies from 20 to 40% of the total product volume, and differs from manufacturer to manufacturer. However, epoxy resin is typically used. The Basalt FRP rebar is then pre-stressed to up to 50% of its ultimate strength, prior to inclusion in the concrete beam. Basalt FRP tendons have a tensile strength in order of 1000 – 1300 MPa. In comparison,steel reinforcement has a tensile strength of around 500 MPa. The elastic module of basalt fibre is much lower than steel, of around 70 GPa . One of the main advantages of using Basalt FRP as a strengthening material in concrete is that it is non-corrosive . This property is advantageous in structures under severe attack from salty or damp environments, for example, the top layer of reinforcement in bridge decks, in concrete floors in multi-storey car parks, groundwork and foundations, or structures located by the coast. In conventional houses, Basalt FRP bars offer the possibility of reducing the amount of concrete required, and may allow for thinner concrete members because of the strength and corrosion-resistant properties of basalt, which requires less passivating layers of concrete to limit the transport of oxidants towards the reinforcement bars. This may also in turn lead to a reduction in material consumption. Reduced material consumption will lead to a reduction in embodied energy and material emissions. On the other hand, the elastic module for non ferrous Basalt FRP tendons is much lower than that for steel. This disadvantage leads to excessive deformation at service limit state compared to steel bars, if the same cross-section area is used. However, compared to steel, basalt fibre does not exhibit yielding during tension. The BFRP material is purely elastic. A relaxation test of the Basalt FRP reinforcement bars has been ongoing at SEL since 2013. Reykjavik University estimate an expected final relaxation value of 6% after 50 years.

Carbon fibre sheets

The automotive world has been obsessed with carbon fiber for decades, ever since the McLaren MP4/1 Formula One race car became the first to use a carbon fiber composite chassis in 1981. Since then, the material’s signature weave, with its legendary blend of strength, stiffness, and low weight, has shown up in all forms of motorsport—as well as virtually every supercar since developed, and a smattering of mainstream road cars.

Beyond Materials carbon fibre sheets are our stiffest and strongest flat material option for structural applications where minimum weight is essential. Depending on product, these sheets are made from uni-directional prepreg and/or twill prepreg fabrics. These plates are manufactured under heated pressure, producing a plate with reduced voids and higher temperature specifications. These sheets are also available with stiffer high modulus fibers and high temperature epoxy.

Used in the aerospace, automotive , manufacturing and robotic industries because of its strength and damage tolerance.

Beyond Materials Group is a growing manufacturer of  carbon fibre materials and can meet your specification and quality requirements for a wide variety of custom carbon fibre applications. From our head office in Gold Coast we are able to ship our carbon fibre products Australia wide.

Gold Coast, Brisbane, Sydney, Adelaide, Melbourne, Perth.