What is Carbon Reinforced Concret (CRC)?

Remediation of the bridge in Naila using carbon reinforced concrete. (Photo © Jörg Singer)

What is carbon reinforced concrete?

Carbon reinforced concrete is a composite of concrete and reinforcement made of carbon fibres (carbon). The special feature lies in the carbon fibres. Up to fifty thousand of these fine filaments are joined together to form long fibres and then a yarn. The yarns are then processed in a textile machine to produce a fabric and are given a stabilising coating (impregnation). The highly load-bearing, rustless reinforcement made of carbon can be expected to have a long life, which is far above the present day constructions made of steel reinforced concrete and thus represents a raw material saving alternative in construction.

The most significant construction material worldwide, steel reinforced concrete, is also the most important construction material in Germany with more than 100 million cubic metres installed per year. Steel is covered by a thick concrete layer to protect it from corrosion. After water, concrete, with approx. 5 billion cubic metres, is the most used raw material worldwide.

Concrete per se is made of cement, sand, gravel and water. 1.6 billion tonnes of cement, 10 billion tonnes of aggregate (sand and gravel) and one billion tonnes of water per year are used worldwide for the new build and renovation of buildings and bridges.

The change in material from steel reinforced concrete to carbon reinforced concrete with the carbon reinforced concrete construction method enables, on the one hand, a material saving of up to 80 % and on the other hand, it reduces the energy requirement and CO2 emissions by up to 50 %.

However, until now, petroleum is used to produce carbon – as it is currently inexpensive and, compared to the quantities required, is sufficiently available. In future, however, the carbon cold be produced from lignin, waste wood products, which are left over in paper production.