I received my Master’s degree in chemical engineering from SU, USA. I worked as a writer and researcher for Fortune 500 company clients.
The sheer truth is that about 39% of global carbon emissions arise from building and construction industries. Out of this value, 28% are operational emissions (that is emissions from energy used to heat, cool, and light the buildings), and 11% are emissions from construction processes occurring throughout the buildings' lifecycle.
One Avenue Of Solution - Carbon Emissions Utilized By Microbes To Produce Sustainable Concrete.
Imagine a building that is alive! Living concretes have been invented by the researcher Wil Srubar who is from the University of Colorado Boulder. These are called Engineered living building materials (LBMs). LBMs were created by inoculating Synechococcus sp. PCC 7002, a photosynthetic cyanobacterium into a solution of sand and gelatin. On a practical scale, the bacterias also called the green microbes, absorbs carbon dioxide emissions from the atmosphere as a source of energy to produce calcium carbonate. This further mineralizes the gelatin, binding together with sand and forms a brick.
Generally, in buildings and construction wood is used. Wood is a biological material, however, it isn't alive. Whereas, cyanobacteria inside the brick are alive. The microbes need to be able to stay alive inside the concrete with respect to the temperature, humidity of the environment for a long time. According to their findings, Microbials survival in the LBMs was 9% when exposed at 4C and 50% Relative humidity, and 14% at 4C 100% relative humidity after 30 days. This means that the bacteria stayed alive inside the bricks making it capable enough to not only absorb carbon emissions successfully but also heals any cracks occurring on the inside of the concrete and avoid pumping the emissions back into the air.
It was observed the microbes were able to grow and multiply, the presence of three successive regeneration of microbes derived from one parent generation in the brick. This meant that if we chopped a brick, each of the chopped pieces would grow into a new brick. So, the bricks would regenerate by themselves. What's interesting is that these living bricks are durable as well. The living bricks proved to show the same strength as the bricks used by contractors today, that too in different humidity conditions.
However, one drawback is that the bacteria require humid conditions in order to survive. These conditions are absent in the arid regions of the world. To make these living concrete more accessible to every region, efforts are in Progress to engineer bacterias that can be more resistant and remain alive in arid regions.
The Larger Picture
Present available industrial technologies are capable of injecting carbon emissions into the concrete mix. The carbon dioxide reacts with the calcium in the cement and permanently forms calcium carbonate minerals. However, they do not have self-healing properties. At the manufacturing level, the new microbial method to produce building materials has no carbon dioxide emissions during production, compared to the conventional method. Also, faster manufacturing rate because of microbes. The living concrete could be especially beneficial for underwater infrastructures, tanks, buildings, etc where maintenance is difficult. As mentioned, we might live in buildings that are alive in the near future!
This content is accurate and true to the best of the author’s knowledge and is not meant to substitute for formal and individualized advice from a qualified professional.
© 2021 Nikita Nandakumar Thattamprambil