Mike Hernandez, Technical Director The Voice Newsletter September 2023
Several years ago, climate change and sustainability were not something the concrete construction community would hear much about. Now action on sustainability is increasing all around us, which translates to less cement in concrete and more supplemental cementitious materials. In the last few years, the following has occurred:
The federal government has a National Climate Task Force and the 2022 ~$500 billion dollar “Inflation Reduction Act” allocates billions toward lowering carbon (clinker) in concrete.
The United Nations is “empowering the next generation for climate justice” on their website homepage and meeting this 9/18 – 9/19/23 to strength international commitments to their 17 Sustainable Development Goals targeting major progress by 2030.
State and local governments like California and Colorado are legislating through programs like the Colorado “Buy Clean Act” to establish maximum acceptable Global Warming Potential (GWP) limits.
ACI has introduced NEU, A Center of Excellence for Carbon Neutral Concrete and a Concrete Construction Sustainability and Resilience Assessor certification along with committees 130 Sustainability and 323 Low Carbon Concrete Code. In addition, committees 318 structural code and ACI 301 concrete specification now have sustainability subcommittees.
The Portland Cement Association (PCA) has the Roadmap to Carbon Neutrality which has a goal to be carbon neutral by 2050. A map of all the PCA affiliated cement facilities that have switched to IL and therefore are no longer manufacturing I/II cement can be found here: https://www.greenercement.com/plcavailability. In 2022 – 2023 the cement industry substantially increased the use of type IL cement from near zero to ~40% of the U.S. market.
Limestone Calcined Clay Cement or LC3 which only uses 50% clinker in the cement vs ~95% clinker in Type I/II cement is the next generation of cement in development. It is already in use in India and parts of Africa through a collaboration with the Swiss Global Programme in Climate Change. Additional information here: https://lc3.ch/
NRMCA has a Sustainable Concrete Plant Certification and a Concrete Sustainability Professional Certification. Environmental Product Declarations (EPD’s), which have the environmental impact of specific concrete mixes are being hosted on their website.
ASCC initiated a Sustainability Committee, chaired by Bev Garnant and Bruce Suprenant, in June of 2023 and a Type IL cement subcommittee emerged shortly thereafter. ASCC’s “Alert! Portland Limestone Cement” can be downloaded from the member Sustainability section of our website to share with your customers.
ASCC and ACI Committee 302 had a 15-question survey on Type IL portland limestone cement concrete on ACI’s website: https://www.concrete.org/news/newsdetail.aspx?f=51739116
ASCC is in discussions to provide discounted EPD’s to our members. ASCC Members that are likely interested are members who put up mobile batch plants and are not NRMCA members.
All of this to say that ASCC members will be expected to be engaged in sustainably initiatives across the country probably sooner than we realize. ASCC will continue to advocate for research and testing so that concrete contractors are not alone in finding the unexpected outcomes of new blends of concrete. We need your success stories on projects that went well and how you overcame challenges on projects that did not go as expected. Through our collaboration we can navigate a low carbon concrete future.