CFS is a CO₂ Capture Technology

Given the challenges presented by the climate emergency, the construction industry is performing a handbrake turn in the type of materials being used for building and their manufacture. This is leading to a slew of composite materials being developed.

CarobonFibreStone (CFS®) is one of those materials and is a great answer to the problems of constructing within the limits of a reduced carbon footprint. 

It has the potential to replace concrete, steel, and aluminium materials that cause intensive air pollution and high CO2 output levels. But CFS® has the ability not only to use less carbon, but also, when the carbon fibre is produced from biomass, to act as a form of carbon capture, and so become a carbon-negative building material.

How is this possible?

Conventional building materials cause immense greenhouse gas emissions worldwide. With carbonfibrestone(CFS®) we created a novel building material that could contribute to the decarbonisation of construction: CFS® is a composite building material made of hard rock, algae-based carbon fibres and biochar. It can permanently store CO₂ in solid form.

Building materials made of

  • slabs of natural stone like granite and basalt, can be produced with zero-emissions
  • carbon fibre made from bio-based oils
  • bio-based resin
  • biochar as insulation material
 

Proof of carbon negativity by

  • CO2 storage in stone and its manufacturing waste in form of Enhanced Rock Weathering of Stone  (that is, Stone Powder/Flour)
  • CO2 storage in carbon fibre and resin
  • CO2 storage in biochar
 

Additional effects:

  • replacement of steel
  • replacement of cement
  • replacement of aluminium
 

Carbon Dioxide Removal(CDR) methods involved:

  • Weathering of rock in machine-cut stone plates and stone waste in form of flour from the cutting process
  • Permanent storage of carbon in the carbon fibre, which will be stored away after use
  • Production of biochar for insulation which will be stored in the building
  • All materials can be separated and reused after dismantling of the building
    • these effects are being quantified by LCA and TEA
    • a house wall demonstrator will be built, addressing fire protection and mechanical needs
    • the carbon fibre can be safely stored away after use for millions of years
 

Structures from Carbon Fibre Stone (CFS®) are more stable and lighter than Aluminium, non-rusting and stiff like steel. We have, for example, created a structure for measurement instrumentation used in steel plants for I-beam production.

Understanding why biochar is important for CO2 reduction

Through photosynthesis, biomass accumulates carbon, which via pyrolysis (heating without oxygen) becomes biochar — a highly porous, stable and durable form of carbon that can effectively store CO2 for extended periods and provide a wide range of co-benefits.

Why use natural stone?

The cutting of natural stone absorbs CO2. Although the extraction is harmless to health, it is an indigenous resource whose occurrence is limited. However, the deposits of hard stone such as granite are 50 times higher than those of the soft stone limestone from which cement is made. Natural stone has a low density (2500–3000 kg/m3, aluminium is 2700kg/m3) and thermal conductivity. Therefore, it is suitable as thermal mass. At present, they are mainly used outdoors but also indoors as floor coverings, façade cladding, window sills, stair treads or roofing.

To make this work carbon fibre has to be produced using organics

Carbon fibres are manufactured synthetically and consist of at least 90% carbon. They are currently still produced from synthetic fossil oils, pitch, or viscose. Research is already investigating in PAN-based (polyacrylonitrile) carbon fibres from bio-oils that can bind CO2 (TU Munich, Algae Technology Centre). Carbon fibres are characterised by their special strength in the direction of the fibres at a comparatively low weight. They are also weather and temperature resistant. In order to make use of their mechanical properties, they are usually used as carbon fibre reinforced plastics (CFRP) and therefore cannot be recycled on high quality.

Why CFS® works

As the production of carbon fibre is energy-intensive, the advantage of the composite material lies in the saving of solid carbon material. The carbon fibre is laid on the surface of the stone and can be peeled off manually at the end of its life. Thus, the composite is broken down into stone and carbon coating and can be stored (perhaps underground) and therefore acts as carbon capture.

Environmental Benefits

Educational Video by Veolia

  • Carbon concrete could contribute to more flexible and resource-saving construction processes, and switching to carbon concrete could reduce the CO2 emissions from construction by up to 70%.

  • You can make concrete much thinner while being able to carry heavy loads.

  • Natural stone is more aesthetically pleasing to the eye than metal. Creative flair can be employed with these new materials as a benefit at no additional cost.
  • Unlimited natural material availability.