The world is their oyster
The partners at Sustainable Bio & Waste Resources for Construction (SB&WRC) research project have continued to make significant progress towards the design and manufacture of the first insulation prototypes made from biobased and recycled materials. The University of Brighton is one of the English partners of the SB&WRC project. Their deep involvement in alternative building technologies has led to impressive experiments and results that continue to inspire researchers and practitioners.
Duncan, Dr Ryan Woodard, Nick Gant of Community 21, Dr. Ryan Southall and Ben Bosence of Local Works Studio are looking at the potentials of sourcing waste material flows local to construction sites to provide material for insulation and rain screen cladding of social housing developments.
Over 7 million tonnes of mollusc shells are discarded by the seafood industry every year. These shells consist of over 90% calcium carbonate. Crushed shells can reduce soil acidity in agriculture or be fed to egg-laying hens as a calcium supplement. However calcium carbonate is also a common ingredient in the production of cement that is one of the largest sources of harmful CO2 emissions. Currently the majority of the cement industry’s calcium carbonate is coming from ecologically harmful and unsustainable limestone mining.
One of the projects has the University of Brighton team partnering with restaurants recycling oyster shells into beautiful tiles suitable to hang on the outside of buildings. One restaurant, ‘English’s of Brighton’, who throw away over 50,000 oyster shells annually, have donated shells to the project. Local Works Studio fire some shells to 900°C to create ‘quick lime’ and mix it with unfired crushed oyster shells forming an aggregate. Pressing the mixture into silicone castes there is a natural chemical reaction when water is added to the mix creating some heat. This hydraulic reaction is similar to concrete ‘curing’. After about 3 weeks the tiles are hard enough to hang on a building. Ben from Local Works states that “We’re working on 50kg of oyster per m2 of hung tile. Traditional clay tiles are 78kg/m2.” So not only we are working with waste material, but the manufacturing process is more efficient that the current system.