Concrete is possibly the most common building material on earth, yet it just so happens to be a significant contributor to carbon emissions. Fortunately, there’s a heartening trend in the field of concrete: low-carbon concrete. Researchers worldwide are creating new mixes, new processes, and new ways of thinking about a material that we often take for granted.
The Global movement toward Low-Carbon Concrete
The problem’s importance is evident, and it is being taken seriously. Despite all the political and economic imbalances and upheavals currently occurring at the global level, some countries have started making necessary decisions and even implementing them. The United States is one of them.
On March 25, the House of Representatives approved a draft bill for the promotion of the commercial use of low-emission cement, asphalt and concrete.
The majority of the clients and stakeholders of cement, concrete, and asphalt companies want their products to be low-emission. That is why the proposal went through with a majority of members of the House of Representatives voting in its favor, with 350 yeas and 73 nays.
Reason for using low carbon concrete
Concrete is typically comprised of a mere 10–15% cement. Yet, up to 95% of concrete’s embodied carbon comes from cement production. The huge carbon footprint is due to the chemical reactions that take place when raw materials are heated to produce Portland cement, as well as the emissions that result from coal or gas burning in the calcination process.
What is low carbon concrete made of?
Low carbon concrete is made by mixing industrial cement with mineral substances like calcined clays, fly ash, or blast-furnace slag. By altering the mix of these additives, the carbon footprint of the concrete can be reduced by nearly 70%.
How to Produce Lower Carbon Concrete
Producing lower carbon concrete involves a range of solutions. Since concrete consists of so many different ingredients, there are numerous ways to decrease the carbon footprint of each component and every process.
Primarily, decarbonization efforts are focused on three fronts: low-carbon fuels, low-carbon blended cement, and carbon capture, utilization, and storage technologies.
1. Low-Carbon Fuels
Over the last several years, the concrete industry has been working on fuel efficiency as a major way to save money and lower emissions. More recently, the industry has started examining a switch away from traditional fuels, such as coal, to low-carbon fuels such as renewable natural gas, waste fuels such as biomass, and perhaps even carbon-neutral fuels.
Alternative fuels can lower cement production carbon emissions by up to 40%, based on the manner in which particular materials are accounted for in carbon calculations.
2. Low-Carbon Blended Cements
The majority of producers are already blending Portland Limestone Cements (PLCs) and supplementary cementitious materials (SCMs) into their cement and concrete products. These activities decrease the quantity of cement in concrete and reduce the emissions related to cement production. By the additional optimization of the use of these materials, cement and concrete emissions can be decreased significantly. For instance, PLCs incorporate uncalcified limestone into the cement grinding phase of the process, which can decrease the carbon footprint of concrete by an additional 5-10%.
3. Carbon Capture, Utilization, and Storage Technologies
Among the most promising trends in the concrete industry is the innovation in carbon capture, utilization, and storage (CCUS) technologies.
Carbon capture enables the capture of up to 100% of the carbon emissions resulting from cement production. The captured emissions can be safely stored underground, injected into concrete to strengthen it, or utilized to create other products like synthetic aggregates or fuels.
“If you will be worried about how the Lower Carbon Concrete will be applied in the construction process, there is some project that already apply this concept.”
Lower Carbon Concrete Projects
– Amazon HQ2
– Infosys Technology and Innovation Hub
Conclusion
Toward a New Standard in Concrete
Low-carbon concrete is a promising path to emissions reduction without performance reduction. Sanctioned by governments and industry alike, and tested by use in high-profile projects like Amazon HQ2, the lesson is clear: sustainable concrete solutions are not just on the horizon—they’re on the job. Embracing innovations like these is critical to a sustainable tomorrow.
