Basalt fibres are non-combustible, they have high chemical stability,
and good resistance to weather, alkaline and acids exposure. Moreover, basalt
fibres can be used from very low temperatures (i.e. about _200°C) up to the
comparative high temperatures (i.e. in the range 600-800°C). High modulus, good
strength and elastic behaviour make also this kind of fibres a good alternative
to the traditional ones and in particular, continuous basalt fibres are
competitive with glass fibres. Another feature of the basalt fibres is their
good compatibility with the matrix materials.
Basalt fibres can be considered environmentally friendly and
non-hazardous materials. It is not a new material, basalt originates from
volcanic magma and flood volcanoes, a very hot fluid or semifluid material
under the earth’s crust, solidified in the open air. Basalt is a common term
used for a variety of volcanic rocks, which are gray, dark in color, formed
from the molten lava after solidification.
The basalt has low density like 2.8 g/cc to 2.9 g/cc, which is much
lower than metal (steel) and closer to carbon and glass fibers though cheaper
than carbon fiber and high strength than glass fiber. Hence basalt is suitable
as low weight cheaper tough composite materials.
The first attempts to transform basalt rock into fibers by extrusion
started at the beginning of the 1920’s and were attributed to the French Paul
Dh`e, that was granted a U.S. Patent in 1922. Around 1960, Soviet Union began
to investigate basalt fiber applications too, particularly for military and
aerospace purposes, succeeding in developing the first attempt of production
technology for continuous basalt fibers. In subsequent years many technical
studies have been conducted in Europe and more recently in China, aiming to
improve quality of the manufacturing process as well as to enhance the
physico-chemical features and mechanical performance of basalt fibers.