Caltrans Secures $32 Million for Concrete Decarbonization Programs

The Federal Highways Administration (FHWA) yesterday announced $1.2 billion in federal funding to support state transportation departments in reducing carbon emissions from transportation infrastructure materials. California's Department of Transportation (Caltrans) was awarded $32 million to establish programs aimed at reducing the embodied carbon emissions of concrete and asphalt used in the state's transportation projects. These programs, if fully implemented, would set California on a strong path toward better aligning its infrastructure investments with its strong climate goals.

As my colleagues write, the FHWA Low Carbon Transportation Materials program is a landmark initiative that will accelerate the transition to lower-carbon materials in the roads, bridges, and highways that form the backbone of the nation's transportation system.

Concrete Decarbonization in California

Concrete and asphalt are two of the most emission-intensive materials used in transportation infrastructure, and Caltrans uses them in large quantities. While California has made strides in addressing emissions from other materials, including steel, glass, and insulation, the state is just beginning to develop data collection rules for concrete and asphalt emissions. This federal funding could accelerate finalization and implementation of these programs and establish California as a leader in concrete decarbonization.

California has long been a climate policy leader, and has begun to develop a comprehensive framework to reduce emissions in the cement and concrete sectors. In 2021, the state adopted SB 596 (Becker) requiring all cement used in California to be net-zero emission by 2045. While SB 596 covers cement, emission reduction interventions at the concrete level, such as SCM blending and aggregate optimization - which reduce emissions by using less of the most emissions-intensive element: cement - will be crucial to cost-effectively meet SB 596's targets.

Expanding California's Concrete Emission Reduction Programs

California has adopted a suite of policies in recent years that require reduction of embodied emissions. Buy Clean California requires emission reduction of flat glass, insulation, and steel used in state projects but notably does not cover concrete. AB 2446 (2022) and AB 43 (2023) require reduction of embodied emissions of building materials used in California. Recent amendments to CALGreen, the state's green building code, include embodied emission reduction requirements for buildings over 100,000 square feet.

While these policies establish a foundation for emissions reduction from cement and concrete, to date, a comprehensive strategy for emissions reductions for cement, concrete, and asphalt used in transportation infrastructure has been missing.

In fact, California is lagging in the adoption of Portland Limestone Cement (type 1L), a blended cement that can reduce embodied emissions of cement by 10 percent compared to traditional Portland cement. While states including Colorado, Minnesota, Maryland, Indiana, Tennessee, and others, have adopted Type 1L at rates exceeding 90 percent, the material makes up less than 8 percent of California's cement market.

Programs Caltrans implements from this FHWA funding could accelerate adoption of Type 1L cement, blended cements that go further and reduce embodied emissions up to 50 percent, and, eventually, near-zero emission cements. Importantly, many types of lower-carbon concretes have improved strength and durability.

Potential Caltrans Emission Reduction Programs

Caltrans' funding proposal outlined a series of innovative programs aimed at scaling the use of low-carbon concrete and asphalt in state infrastructure projects. Key elements of the proposal include:

• Development of performance-based specifications: Shifting from rigid, prescriptive material specifications to more flexible, performance-based criteria that encourage the use of low-carbon alternatives.
• Environmental Product Declarations (EPDs)​: Expanding data collection to include EPDs for concrete and asphalt, enabling the state to benchmark emissions and track reductions over time.
• Pilot projects​: Testing low-carbon concrete and asphalt in real-world projects, providing data and experience to guide future decisions.
• Cali Road (I-10) Pavement Evaluation Program​: A pilot project to test low-carbon materials on a stretch road parallel to I-10, modeled after Minnesota's successful MnRoad project.
• Training and stakeholder outreach​: Ensuring that Caltrans staff and contractors are well-equipped to implement new materials and technologies.

​These programs include a mix of transparency initiatives, emission reduction requirements, and materials testing and demonstration, and represent an enormous opportunity to decarbonize transportation and industrial emissions. The total grant awarded, $32 million, is less than the amount requested to implement all of these programs. Ideally there will be future state or federal funding opportunities to fill in the funding gaps on the full suite of programs. In the shorter term, however, the grant will still enable advancement of a significant portion of this suite of concrete decarbonization programs.

What's Next

Reducing emissions from transportation infrastructure is essential for meeting California's climate goals. This federal funding represents a major opportunity to accelerate Caltrans' - and California's - concrete decarbonization efforts.

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