Bio-mineralisation is the process by which living organisms can produce minerals. and a possible method to help promote masonry crack remediation. Scientists at the Structural Engineering Research Centre (SERC) in Chennai now believe they are getting closer to developing a ‘self-healing’ concrete for commercial use.
“There are only a few ongoing research projects happening across the world on the use of micro-organisms in developing self-healing construction materials. SERC is working with cell biologists to develop this concrete,” said SERC director Nagesh R Iyer.
The bacteria would be able to produce the minerals that would help repair and cover building cracks. Not only does this self-healing propensity obviate the need for expensive and time-consuming repair work, it can also significantly reduce the cost of concrete structures by enabling engineers to dispense with steel reinforcement, which is the more traditional method used to prevent cracks from becoming too large.
SERC is also developing an innovative, cost-effective method for the production of high-performance thin sheeted, fabric-reinforced cement composites.
“This method will help produce a new class of high performance oriented fabric cement material, which may open the way for a multitude of new products and applications. It is water as well as fire proof,” said Iyer.
The Delft University of Technology in the Netherlands has also been working on the incorporation of bacteria into concrete. The bacteria produce calcium carbonate – akin to mineral limestone, as a waste product, which can naturally fill in the cracks or holes.
Elsewhere, green building start-up bioMason has developed a method for “growing” bricks via the use of bacterial colonies, thus dispensing with the need for energy-intensive manufacturing processes. The biomass bricks also make use of raw materials as cheap and commonplace as salt and yeast extracts, and are capable of recycling waste products such as urea.
Meanwhile Ecovative, a manufacturing company founded to develop alternate uses for the mushroom mycelium, has developed a microscopic, fibrous fungus which, when bound to agricultural waste, creates a strong, resilient matrix that can be moulded into any shape.
Architecture firm The Living and structural engineers Arup were the first collaboration to use the mushroom bricks in a building open to the public. Their fungal tower was on show at MOMA in New York.
The structure comprised 10,000 organically grown bricks that reached 40 feet in height and inverted the logic of load-bearing brick construction to create a gravity-defying effect — instead of being thick and dense at the bottom, it was thin and porous.
The structure was calibrated to create a cool micro-climate in the summer by drawing in cool air at the bottom and expelling hot air from the top.