Sustainable building with concrete? Is that possible?

Concrete is the single most widely used material in the world – and it has a carbon footprint to match.  Just the production of cement is responsable for about 5 % of the global carbon emissions.

With 2017's motto "greencrete" our goal is to organize and create our concrete canoe eco-friendly, sustainable and to put out a statement at the 16. German Concrete Canoe Regatta.

 

Our competition canoe is supposed to be eco-friendly, but athletic and dynamic at the same time. How do you approach that problem?

We set out our four key points to focus on:

  • our concrete mixture
  • the reinforcement
  • the formwork
  • and our overall appearance at the regatta

 

 

Concrete Mixture

To maintain the processability and simultaneously guaranteeing  the best strength properties, we agreed to use a CEM III 52,5R cement, recycled expanded glass granulate, powdered limestone, a flow improver and green pigments.

Reinforcement

Natural fibers were our first choice for our concrete reinforcement. Although natural fibers are not often used in the construction industry, we found a company that creates high performing grids made out of flax fibers. Since Bcomp's powerRibs were never used in a conrete matrix, we had to build samples and test them for bending strength. The properties were not as good as the samples reinforced with carbon fibers, still we decided to use the flax fibers. That is the reason why our canoe is called "FlaXship".

Formwork

Recycling was a important key part in the process. 50 milled and mutually sequenced styrodur pannels are giving the canoe its shape. To even out inequalities, we applied a thin layer of gypsum. The overall construction was compressed with OSB boards. A wax layer was used as the seperating agent pre-concreting.