Floating land of living Root Concrete©
Erik Hobijn (Gevouwen Oevers) developed a completely new, 100% plant-based and circular building block: Wortelbeton©. This innovative material is made from ditch residue – carefully selected reed rhizomes (rootstocks) – that grow under controlled conditions with simulated tides and a unique mixture of nutrients. This creates a new way of “soil farming” in which nature and technology merge.
The Waterkaravaan includes three blocks of Wortelbeton©, which were cultivated over a period of two years. Because reed stems and rhizomes can contain a lot of air, these blocks float. The air channels ensure that the reeds also receive sufficient oxygen in wet conditions. We are very curious to see how the blocks will fare in the Waterkaravaan. The expectation is that the three blocks will grow together underwater. Although a single reed stalk is fragile, a floating reed bed is sturdy because all the reed stalks lean against each other.
To protect the Wortelbeton© from washing away, particularly during transport during the summer expedition, we placed it in an underwater bag. We were looking for something made from a natural, non-toxic material that was sturdy and would remain intact for the time being. Basaltex has developed textile products made from basalt stone.
Their BAS 350A fabric was used for the outer bag because this fabric has not been treated with PU to prevent fraying (non-functionalised) and is suitable for use as geotextile. It is therefore attached to the wooden floating frame with a perforation-free fastening. Inside, a layer of Basaltex needlefelt (felt) has been applied to provide extra space for micro-organisms and a waterfiltering effect.
