More than 4 billion tons of cement are manufactured every year globally. That cement produces nearly 30 billion tons of concrete every year. Our per capita use of concrete has almost doubled over the past 20 years.
Reducing the carbon footprint of cement and concrete, the most widely used building materials today, is an enormous challenge, motes Dr. Randolph Kirchain, Co-Director of the Concrete Sustainability Hub at the Massachusetts Institute of Technology (MIT). Equally daunting are the measures required to reach the goal of carbon neutrality by 2050.
Lowering the carbon footprint of concrete begins with reducing the footprint of cement production, notes Dr. Kirchain, then by leveraging every opportunity available in producing and using concrete and acting upon any net-negative applications needed to reach our goal.
These observations are part of a fascinating presentation by Dr. Kirchain as part of a series of webinars on Pathways to Resilience and Carbon Neutrality produced by the Pacific Northwest Building Resilience Coalition.
In his presentation, Dr. Kirchain demonstrates how cement emissions could be lowered by 24 percent by 2050 despite increased production by over 20 percent. Carbon capture and storage will account for 48% of that decrease, followed by clinker substitution, accounting for 37 percent of the required GHG remissions reduction.
Equally impressive gains in emissions reduction are possible in producing and using concrete, notes Dr. Kirchain. Combining changes to the materials used in concrete production and injecting captured CO2 into the concrete mixture will increase its strength, durability, and real-world performance.
Strengthening pavements with concrete improves the performance of vehicles on the road, thereby reducing their emissions. Also, exposed concrete buildings reabsorb CO2 from the atmosphere and permanently store it through natural carbonation.
That is why building design and the mandated use of lower carbon building materials are essential, notes Dr. Kirchain. Including in project specifications, softer carbon materials and processes will stimulate further research on lowering the carbon content of structures.
He emphasized that an entire lifecycle perspective is needed to evaluate concrete’s environmental impact properly. That means assessing its production, design and construction, lifetime use, end-of-life material recovery and carbon uptake.By protecting our communities and infrastructure with more resilient building materials, we can avoid massive rebuilding following disasters, save lives and lower property damage, notes Dr. Kirchain. All these matter when we consider the actual carbon footprint of the built environment.
In partnership with the Pacific Northwest Economic Region, Dr. Kirchain’s presentation is one of six webinars organized in 2021 by the Pacific Northwest Building Resilience Coalition.
You can watch this inspiring webinar here. More information on this webinar series is available here.
Each webinar is available on the Pacific Northwest Building Resilience Coalition YouTube channel here.
