Written by Morgan Kaenzig de Denus, AMAST Content
The construction industry is constantly changing. The introduction of new techniques, materials, and technology has allowed architects, engineers, and builders to push the boundaries and create innovative structures and buildings. In 1853, François Coignet built the world’s first iron-reinforced concrete structure, and in 1855, the Bessemer Method provided an efficient way of creating steel. By the twentieth century, the use of glass, steel, and reinforced concrete in structures exploded in popularity. Today, carbon fiber is on the rise.
What Is Carbon Fiber?
Carbon fiber consists of thin strands of carbon atoms that are bound in a crystalline formation. It’s a very versatile material. These strands can be twisted together, woven into a fabric, formed with different densities, and even molded into permanent shapes.
Carbon fiber-reinforced polymers, or CFRPs, can be made from petroleum-based polyacrylonitrile or lignin. Carbon atoms can be bonded with resin using heat, and the resulting composite material is very strong, because the resin transfers loads between the fibers. Polyester, epoxy, and vinyl ester resins are used in the bonding process most often.
What Can It Be Used For?
Carbon fiber has been used in everything from laptops to fishing rods to vehicles, but the construction industry has been slow to adapt to using it. Instead, the industry continues to rely on previously established building materials and techniques. However, this material has the potential to revolutionize the construction industry. It can reinforce and strengthen a variety of building materials like concrete, timber, steel, and masonry, resulting in structures that are stronger, lighter, and more durable.
Bridges
In the last few years, carbon fiber-reinforced concrete bridges have grown as an alternative for the more traditional steel-reinforced concrete bridges. The Advanced Structures and Composites Center at the University of Maine has used carbon fiber-reinforced concrete to develop a composite arch bridge system that had been used in the construction of 23 bridges by April of 2019.
Buildings
The use of carbon fiber-reinforced concrete in buildings has also started to take off, and it has been used in retrofits to increase the load capacity of existing buildings. It also adds flexure in reinforced concrete structures, and has been used to strengthen cast-iron beams and replace prestressed materials.
The CUBE, or Carbonhaus, signifies an important moment for carbon fiber. This 5-million-euro project is the first building made entirely of carbon fiber-reinforced concrete in the world, and its construction began in the summer of 2020 at the Technical University of Dresden. It is a two-story building that features twenty-four meters of seamless concrete and two parts: the precast box and the twise. The twise is a double-curved roof whose construction was possible thanks to carbon fiber’s lighter weight and increased flexibility.
What Are the Benefits of Building with Carbon Fiber?
High Strength
It is five times stronger than steel, making it an ideal construction material. Using this material is particularly beneficial in high load-bearing structures. In addition to having high specific strength, it has high tensile strength, which means it can withstand a large amount of stress while being pulled or stretched before failing.
Low Weight
Carbon fiber is light, resulting in an impressive strength-to-weight ratio. Its low weight also reduces the need for support. For example, a roof made from carbon fiber-reinforced concrete would need fewer load-bearing walls or columns than one made from steel-reinforced concrete. This would afford the structure more flexibility in its design and could help reduce the project’s timeline and cost.
High Stiffness
Carbon fiber also has high stiffness, so it can return to its original form after experiencing force. If it’s used alongside other materials, carbon fiber-reinforced concrete will attract more load.
Corrosion Resistance and Chemical Stability
Carbon fiber has a high chemical resistance and it is resistant to corrosion, so it can retain its original properties as it is exposed to chemicals over time. Using CFRP instead of steel-reinforced concrete in structures can eliminate concrete deterioration from steel corrosion as well as reduce the need for maintenance and repairs. However, the resin used to bind the carbon together is sensitive to sunlight, so it’s important to keep the CFRP away from direct sunlight.
Low Thermal Expansion
As the temperature fluctuates, most materials may expand or contract. If it’s hot, materials will expand; if it’s cold, they’ll contract. Carbon fiber has a low thermal expansion value, so it is an excellent material to use in places where the smallest expansion or contraction of material has the potential to have a large impact on the project.
Lower Cost
While carbon fiber itself is currently more expensive than steel and most other concrete reinforcement materials, using carbon fiber reinforcements can actually reduce the cost of a project. This material is light, so fewer workers and heavy equipment are needed during the construction process. It’s also stronger, more durable, and less corrosive than steel, so concrete structures reinforced with carbon fiber are less likely to need maintenance in the future.
What’s Next for Carbon Fiber?
In the past decade, the cost of carbon fiber decreased from $150/pound to $10/pound, and its price is likely to continue to decline as new production techniques are discovered. The Autodesk Technology Center in Boston or Hitexbau may help contribute towards a reduction in the price of carbon fiber.
The Autodesk Technology Center in Boston, or Build Space, is currently researching composite carbon-fiber materials as well as various robotic fabrication techniques that will make producing these materials quicker and cheaper. Once carbon fiber’s fabrication is fast and cost-effective, it will likely be used in more projects.
In Augsburg, Germany, Hitexbau developed a highly automated process for producing carbon fiber reinforcements. Their production line allows for the production of large volumes of carbon fiber reinforcements as well as carbon fiber reinforcements with large dimensions.
It’s likely that using carbon fiber in construction will continue to increase in the coming years as manufacturing becomes faster and more affordable.
Citations
Alderton, M., Gustafson, M., Hays, Z., & Wolf, M. (2021, April 06). Carbon fiber building: The superhero of construction’s future? Retrieved April 9, 2021, from https://redshift.autodesk.com/carbon-fiber-building/
Carbon fibre as a recent material use in construction. (n.d.). Retrieved April 10, 2021, from https://www.engineeringcivil.com/carbon-fibre-as-a-recent-material-use-in-construction.html
Carbon fibres production properties and potential use. (2017, June 25). Retrieved April 10, 2021, from https://www.materialsciencejournal.org/vol14no1/carbon-fibres-production-properties-and-potential-use/
Is carbon fiber all it’s cracked up to be? (2019, April 25). Retrieved April 9, 2021, from https://www.architectmagazine.com/practice/is-carbon-fiber-all-it-cracked-up-to-be_o
Gardiner, G. (2020, June 12). Carbon fiber-reinforced concrete accelerates in Germany. Retrieved April 10, 2021, from https://www.compositesworld.com/news/carbon-fiber-reinforced-concrete-accelerates-in-germany
McLoud, D. (2021, September 21). Michigan expands use of carbon fiber as alternative bridge material. Retrieved April 9, 2021, from https://www.equipmentworld.com/better-roads/article/14972567/michigan-expands-use-of-carbon-fiber-as-alternative-bridge-material
Shetty, C. (2019, January 16). Is Carbon Fiber the Future of the Construction Industry? Retrieved April 10, 2021, from https://www.aranca.com/knowledge-library/articles/business-research/is-carbon-fiber-the-future-of-construction-industry
The world’s first building made from carbon fiber reinforced concrete starts construction in Germany. (2020, June 04). Retrieved April 9, 2021, from https://www.bdcnetwork.com/world%E2%80%99s-first-building-made-carbon-fiber-reinforced-concrete-starts-construction-germany
