We know that usually in the reinforced concrete there is steel, or steel bars are inserted into the cement paste. Little known is the fact that the concrete of beams and pillars can also be reinforced with basalt fiber. Saving energy and with benefits for the environment.
In 2010, ENEA began studying the potential of the basalt fiber in reinforced concrete and in other construction applications. The experimentation also took place thanks to the collaboration with HG GBF, a world player in the production of basalt fiber. The results of what has been called the 'Basalt Project' are encouraging.
First question: what is the basalt? We are talking about a dark or black volcanic rock with two main characteristics: being waterproof and having a low silica (SiO2) content.
Basically the basalt it is volcanic magma that quickly solidified in contact with air or water. The third feature that makes it interesting is that it is the most present rock in the upper part of the oceanic crust. In short, there is a lot of basalt.
Second question: why the basalt can contribute to energy saving? Speaking of the application in the reinforced concrete in replacement of steel, the amount of energy required for the transformation of basalt into elements suitable for productive use is lower than that of metal.
Basalt and steel have a different density and such that at 1 kg of basalt correspond to 2.91 kg of steel. Having made two calculations, for every kg of fiber basalt used to replace steel in the reinforced concrete an energy saving of over 9 kWh can be achieved.
Minor are also the CO₂ emissions of the production and processing processes of basalt fiber compared to that of steel. Furthermore the basalt it has the advantage of being an eco-compatible inert material and at the time of disposal, concrete-basalt constructions do not require a preliminary separation process as occurs for concrete-steel.
ENEA hypothesized that by replacing even only 5% of the steel used in construction with basalt reinforced concrete, the annual energy savings would be over 3.9 million MWh. With lower carbon dioxide emissions equal to about 700 thousand tons every year.
For applications in the reinforced concrete, basalt can be used in two ways: by adding the basalt fiber to the cement paste, or using nets and bars of basalt to replace the steel ones.
Last consideration: it has long been established that the performance of the basalt fiber in reinforced concrete they are equal to or better than steel (but depends on the technology of use) for 'reinforcement' and resistance to corrosion. The basalt however it is less heavy than steel and the entire structure will be lighter. This in construction can be an advantage, as long as all structural calculations are adjusted.