By Sarah Balcombe
Could there be a new style of architecture, in the mix, so to speak, for concrete?
Historically, there’s nothing new about concrete. A sand and cement mixture dating back to Nabatean (Bedouin) traders was used to build the first concrete-like structures around 6500BC, using hydraulic lime as waterproofing for underground cisterns.
Geographically this was possible due to the deposits formed by reactions between limestone and oil shale around 12 million years ago in what is now Israel. Addressing potential structural failure, the Nabateans introduced tamping using specific tools to increase the bonding gel produced by the chemical reaction which naturally occurs during hydration.
This is key to the exciting article in last week’s New York Times, recording the creation of a new kind of concrete, by a team at University of Colorado, Boulder, which utilizes energy to create calcium carbonate.
The energy is released by cyanobacteria, when sand and water are added during a photosynthesis process. Using gelatin as a catalyst assists the speed and formation of bonds, and with moulds/shuttering, a concrete block forms. Though the block is not as strong as conventional concrete, DARPA, the Defense Department research funder was extremely excited by the result, not just due to its initial bright green color and DARPA branding, with a recessed logo on its side, but because of its potential. As a “live” material the block could be cut weeks later, and with the addition of raw materials formed new concrete, with the capacity to generate three new generations per block. This made the concrete itself reproducible, massively reducing its carbon footprint, already reduced by the carbon dioxide absorbing qualities of the cynobacteria. This material also reduces the necessity for “virgin sand” a rapidly depleting natural material required in the manufacture of conventional concrete. According to Dr Srubar, head of the research project, waste materials such as ground glass or recycled concrete could be ground into particles to mimic the sand, forming similar bonds.
As Guy Thompson of the Concrete Centre stated in November’s Concrete Quarterly, “Innovation is an exciting process, but it is also a lengthy and costly one.” He mentioned that the success of new materials can only be secured after years of rigorous testing and price competitiveness. Optimistically though he states “a more collaborative pan-industry approach would help us achieve our goals more quickly”. This concrete could be just the collaborative product that these teams could bring to the marketplace.
If concrete heralded Nabatean and classical civilization, birthed modernism and whose face defined brutalism, what new architecture can we hope for with this new concrete? Certainly a more environmentally friendly, cost- effective and transformative one. Responsive to light could this generate less articulated, more organic facades which store energy efficiently, spurning a new generation of intelligent facades?
In the company of algae walls and mashribiya-like solar facades (above), could this live concrete be the material for a new critical regionalism in an age of diversity?