From breeding, cultivation, seeding and harvesting of future building materials
Prof. Dirk E. Hebel
Professorship of Sustainable Construction, Karlsruhe Institute of Technology
Greenhouse gas emissions, material and energy consumption and waste generation
The urban mine
We are seriously interfering with existing ecosystems, as evidenced by climate change, dying fauna and flora systems and dwindling natural material reserves.
Rethink the construction sector
Filling the gap sustainably
While the first industrial revolution led to an increased shift from regenerative (biological) to non-regenerative material sources (metallic and mineral) in the building sector, a new revolution may be just around the corner, bringing biological aspects back into an otherwise mechanised industrialised world. According to Klaus Schwab, founder and CEO of the World Economic Forum, this would be characterised by a fusion of technologies that blur the boundaries between physical, digital and biological spheres. The concept of industrialised construction within and respecting undisturbed natural cycles does not promote a regression to the pre-industrial age; it seeks to describe ways to progress within the given economic environment in order to modify and ultimately reinvent it. This also applies to the social conditions of production and the cultural acceptance of new materials and construction methods. The introduction of biologically controlled and digitally supported production processes could and must enable economic areas in less industrialised areas of our planet to participate in this revolution.
We will not be able to meet the demand for resources from urban mining alone due to the technologies that do not yet exist to transform materials 100%. We need to increasingly fill this gap with a shift towards regenerative cultivation, breeding and cultivation of future building materials.
Biological building materials
Some of the organic matter that could be transformed into building materials has, interestingly, so far been classified as undesirable or as repulsive in the construction industry. While the pharmaceutical industry, for example, has used bacteria with undisputed success, architecture and construction have not yet activated such capacities. However, bacteria can be used very successfully to make mineral building materials and buildings selfhealing and thus more durable, by using the property of certain bacteria to produce biominerals. Several research groups worldwide are also working on the question of whether this property could replace classic cement and thus revolutionise the concrete industry. The same applies to fungal mycelium. In the construction industry, fungi are associated as undesirable and even dangerous organisms. Yet there are species from which building materials can be grown. Here, the root system of the fungal organism, the so-called mycelium, acts as a cross-linking matrix (glue) of biological waste products, such as rice husks, grain stalks, husks or kernels. Depending on these aggregates, on the type of fungus and on the growth conditions, amazing building products can be obtained here, from insulation materials to new types of building boards. Bamboo, another material that has been used for centuries as a reliable resource for building, has also never reached the level of a successful industrialised building product, as it has always been trapped in the “traditional” drawer. As a new industrially-cultivated building material, however, bamboo’s potential lies in its extremely tensile fibre, which can easily rival today’s metallic building materials. The same applies to flax or hemp fibres. The extraction and industrial reconfiguration of these natural fibres opens up new possibilities in the creation of high-strength biological building materials and components. Added to this is the enormous scope for design offered by digital fabrication.
A self-generating economy
Further information about the author
Prof. Dirk E. Hebel
Professor of Sustainable Construction and Dean of the Faculty of Architecture, KIT Karlsruhe