Cement production and usage affects the environment in some way every year, and cement ranks third in the top ten largest contributors to industrial pollution, according to a new study from the Environmental Protection Agency (EPA).
A group of researchers from the University of Colorado Boulder, in collaboration with colleagues from the National Renewable Energy Laboratory (NREL) and the University of North Carolina Wilmington (UNCW) have developed a unique carbon-neutral technique by which portland cement may be made from biologically grown limestone. This innovative material can significantly reduce the environmental pollution caused by construction activities throughout the world.
Here's an overview of the eco-friendly, carbon-neutral cement.
Cement from biogenic limestone vs. traditional cement
After water, concrete is considered to be the most used material across the globe, after portland cement. Construction activities can not be imagined in North America, Europe, or Asia without concrete.
Wil Srubar, a senior researcher at CU Boulder, emphasized the importance of concrete: "We make more concrete than any other material on the planet, and that means it affects everybody's existence."
Professor Wil Srubar's intention to tackle this dilemma was to burn large quantities of limestone, which results in enormous CO2 emissions. Moreover, the air quality in the area where cement is produced is also greatly harmed as the burning of limestone releases many pollutants and toxic gases into the air.
During his exploration, Professor Srubar noticed naturally constructed calcium carbonate structures near coral reefs. Since he was aware that limestone is also made of calcium carbonate, he thought that limestone might also be grown naturally rather than extracted from the quarry.
After returning to the United States, he and his colleagues decided to cultivate a microalgae called coccolithophores, which are capable of generating biogenic limestone by forming calcium carbonate deposits during photosynthesis. The researchers discovered that, unlike natural limestone which takes millions of years to form beneath the ground, the biogenic version by coccolithophores could be made in real-time.
Coccolithophores produced calcium carbonate in less time than coral reefs that Professor Srubar observed in Thailand. The raw material required for the formation of biogenic limestone in seawater included only dissolved carbon dioxide and sunlight. Additionally, since the microalgae can be used to grow limestone almost anywhere in the world.
Calcium from algae is the future.
Coccolithophores' limestone production is so widespread that you must - permit them to bloom in a water body covering an area of about two million acres, which would take only 0.5% of the country's land.
Biogenic limestone is not only carbon neutral, but also carbon negative, since microalgae remove carbon dioxide from the environment and store it in the form of calcium carbonate. Thus, concrete created from this cement might kick start a new era of sustainable construction across the world.
Now is the time for the industry to correct this extremely serious issue. Professor Srubar believes that we have one of the best, if not the best, strategies for the cement and concrete industry to address its carbon issue.
Professor Srubar received the National Science Foundation's CAREER award in 2020, and their organization recently received a $3.2 million grant from the US Department of Energy (DOE) to expand their research and production of biogenic limestone.
Professor Srubar and his colleagues believe that their novel material has all the potential to replace quarried limestone and save the planet from all the environmental harm it causes.