“The best way to predict future is to design it” – Buckminister Fuller
The construction industry, today, is blooming to cater to the needs of the growing population and expanding cities. Unfortunately, it consumes large amounts of non-renewable resources and adds immensely to the CO2 emissions in the environment during its application and production stage. Cement is the most widely used building material and numerous innovations and research have been developing to reduce its carbon footprint, make it recyclable, and improvise its strength. Microbes have turned the way we live since antiquity, from fermenting the yeast in our bread to curing the world with antibiotics. Today their applications in the field of Biotechnology has come a long way in revolutionizing the modern products and offering sustainable and enhanced options. Bio-cement exploits the potential of materials from microorganisms, thus venturing into the sustainable era of the construction industry. The article discusses the perspective of Bio-cement as an alternate material to traditional cement, its applications, successes, and failures.
The idea of Bio-cement hails from the invention of the involvement of microorganisms in carbonate precipitation. Limestone (Calcium Carbonate CaCO3) along with a few functional additives when heated at temperatures of up to 1500C make traditional cement. The precipitation of calcium carbonate during this process emits large amounts of CO2. Microbially-Induced Carbonate Precipitation (MICP) used in the process of Bio-Cementation requires limestone to be heated at much lesser temperatures, using lesser energy, and has a lower carbon footprint. Thus, making Bio-Cement a rather eco-alternative to traditional cement with 38% better compressive strength than the latter.
Concrete has an undeniable presence in our physical environments today. Thousands of buildings get built in concrete every day while a hundred deteriorate, develop cracks or face corrosion of reinforcement, rendering them unsafe for use. Concerns regarding the detrimental effect of cement in the environment and its long-time durability have resulted in innovative researches globally but there are few success stories. Bio-Cement has a distinct characteristic of being ‘self-healing’, i.e, it can remediate the cracks developed in concrete structures due to the microbial additive and thus increase its useful life. When used in the mortar with bricks, it reduces permeability thus increasing the durability and compressive strength of bricks.
Patented by two scientists, Eric Schlangen and Henk Jonkers, Bio-Concrete comes as a blessing in disguise for the construction industry. It is an eco-friendly as well as an economic alternative that not only regenerates itself when cracks occur but also reduces CO2 levels in the atmosphere and has peculiar aesthetic and thermal advantages. When water seeps into the cracks developed in the concrete, it activates the bacteria, which can otherwise stay dormant for about 200 years. They feed on the calcium lactate which is also present in the bio-cement mixture and produce calcite that fills the space of cracks. The scientists boast the first-ever physical manifestation of bio-cement as a small coast lifeguard station beside a lake. Apart from treating the cracks, the bacteria consume oxygen which helps prevent internal corrosion in concrete. Thus calling off the need for expensive and complex repairs in buildings, entirely. It may also be important to note that the presence of microorganisms does not pose a threat to human health since they can only survive in the alkaline conditions inside the concrete. Another variant of the bio-material is developed as a liquid system which can be sprayed onto acute damages in concrete and allow it to heal.
If you thought that was it to bio-cement, then you may be wrong. The novel state-of-the-art material has more to offer. The presence of microorganisms allows for the growth of a living vegetated façade which can be moderated in terms of its tone, color, finish, and overall aesthetic appeal to suit the building. It can be curated as a one-of-a-kind ‘living’ painting that also possesses the ability to capture solar radiations and thus regulate the building temperatures while acting as an insulator.
Although Bio-Cement has proven to be a very promising alternate, its commercial potential is yet to be fully realized. To bring the ecological material from labs to fields requires a multidisciplinary outlook and in-depth research involving experts from varied backgrounds. The process of bio-cementation needs controlled temperatures, pH levels, concentrations and diffusion rates of nutrients and metabolites, etc. to allow for microbial activities therefore rendering it more complex than the traditional methods. The economic options to using high-grade nutrients in the process also need exploration to reduce the overall operating costs. Yet, bio-cement is a guaranteed shot towards a sustainable future that holds enough potential to turn the tables.