WINNER OF A 2023 CANADIAN ARCHITECT STUDENT AWARD OF EXCELLENCE
This is an interesting exploration—by passing an electric current through the salinated water, you both clean the water and use the resulting crystallized structures to reclaim land. The research process evidenced a wonderful kind of multi-disciplinary process. – Michael Heeney, juror
German-American architect, futurist and inventor Wolf Hilbertz pioneered BioRock in the 1970s as a means of growing artificial reefs to benefit coral and other forms of marine life. When a small electric current is passed between underwater metal electrodes in seawater, dissolved minerals accrete onto the cathode—a material such as rebar, for example—encrusting it with a layer of limestone. For his Master’s thesis, Carleton University Azrieli School of Architecture & Urbanism student Cameron Penney proposed that the heavily salted winter runoff from Toronto’s roads could provide a BioRock growing alternative to seawater, and that the resulting, pollution-sequestering ‘Terrestrial Reefs’ of this concrete-like substance could provide numerous benefits to the city.
Using aquariums as model growing tanks, Penney passed a low-voltage electrical current through scrap metal, along with formed metal and scrap concrete. The process prevents rusting, and the resulting limestone accretion is three times stronger than cement. It is also self-repairing, and its strength increases with age. By conducting interviews with interdisciplinary researchers, Penney learned more about BioRock’s material properties and potential applications. On the negative side, it has a slow growth rate; on the positive, it can be synthesized on an industrial scale, and it can be used to repair concrete at the nano scale.
Penney subdivided the BioRock-deploying speculative design interventions he developed into three categories:
Expansion re-introduces at-risk limestone habitats as a landscape strategy, connecting infill sites with terrestrially growing BioRock. An alvar is a type of landscape in which a thin layer of vegetation grows over outcrops of limestone or dolomite bedrock. The mouth of Toronto’s Don River is a landscape where existing alvars could be helped to flourish through the introduction of BioRock ‘landscape scaffolds’. Here, Penney proposes, BioRock could also be used to create lookouts and sheltered seating areas.
Production includes a manufacturing strategy for growing BioRock scaffolds within decommissioned water treatment reservoirs to reduce urban salt and carbon pollution. The author cites existing open-air tanks at the Humber River water treatment plant as a place where high-salinity runoff could be purified by serving as a BioRock growing medium, and then released into the river.
Repair is an in-situ strategy for renewing the crumbling concrete bents supporting the Gardiner Expressway. Here, 3D-printed BioRock cells are monitored growing chambers that cover and re-cap damaged concrete on the Gardiner’s bents. When the monitor indicates that a repair is complete, the cell’s current is switched off. Penney proposes that the cells could contain a lighting component—an extension of the monitoring—a platinum anode growing component, and gas exchange valves. Once the monitoring component has determined that the repair is complete, the lighting can then be used as a street lamp for the Bentway below. With the potential for each bent to have multiple cells attached to it, the process could supply considerable additional illumination to the underpasses.
FACULTY ADVISOR Lisa Moffitt