Sublime Systems Receives Key ASTM Performance Designation for Its Ultra-Low Carbon Cement, Clearing the Path to Commercializing Fossil-Fuel-Free Cement at Scale

Third party verifies that Sublime Cement™ is as strong and durable as today’s ordinary portland cement (OPC), whose production makes more greenhouse gases than all passenger vehicles combined on planet Earth

Sublime Systems, developers of the only fossil-fuel-free, scalable, drop-in replacement for traditional cement in concrete, announced that its product has obtained ASTM C1157 designation. This industry standard specifies performance requirements across parameters including strength development, durability, and low shrinkage and cracking, and is being increasingly adopted as the industry moves towards performance-based standards. Obtaining the ASTM C1157 designation enables Sublime Cement™ to be used compliantly under major U.S. and international building codes, unlocking a path for it to replace OPC at scale and massively lower the carbon output of global construction infrastructure.

Cement production is currently responsible for 8 percent of global CO₂ emissions. About half the emissions come from the fossil-fuel-fired kilns needed to decompose limestone into lime, and the remaining CO₂ is emitted as a byproduct of this chemical reaction. Sublime Systems’ fossil-fuel-free process forgoes both these steps, replacing the legacy kilns with an electrochemical approach that makes cement at ambient temperature and uses renewable electricity to extract calcium and silicates from a diversity of non-carbonate raw materials. Sublime Cement™ manufactures with a “true-zero” (as opposed to net-zero) approach — it does not require offsets or additional carbon capture and storage (CCS) infrastructure to reduce emissions.

“Sublime was founded to have a swift, massive, and enduring impact on global CO₂ emissions, and we’ve designed our process to avoid CO₂ at every step, rather than polluting and cleaning up afterwards,” Sublime Co-Founder and CEO Leah Ellis, PhD said. “At the same time, we take our responsibility in manufacturing a next-generation product very seriously — we need to make a high-performing cement that is safe and easy to adopt. Data-driven performance-based standards, like ASTM C1157, allow us to solve the right problems: safety and carbon avoidance, rather than adherence to a legacy recipe. Passing the ASTM C1157 standard is an important milestone in showing that Sublime’s low-carbon cement innovation integrates into the same quality concrete building material that the construction industry requires.”

The ASTM C1157 specification is a performance-based standard, a category that is being widely adopted by a range of industries as they allow for novel materials that can be produced with minimal emissions while maintaining rigorous and data-driven standards for safety and performance. ASTM C1157 has more stringent strength requirements than older hydraulic cement standards, ASTM C150 for OPC and ASTM C595 for blended cements, both of which contain prescriptive and performance requirements.

To achieve the ASTM C1157 compliance, Sublime provided its cement to a Cement and Concrete Reference Laboratory-certified third-party for testing. Sublime Cement™ — which is based on the recipe for Roman cement — exceeded all ASTM C1157 General Use performance requirements and outperformed many samples of OPC in ultimate strength and durability. These results suggest the extension of the final product’s long-term service life relative to today’s industry standard. Sublime is currently conducting additional tests measuring its cement’s performance in concrete through third-party ready-mix concrete labs and in field use cases. Sublime’s operational pilot facility has a current design capacity of >100 tonnes of cement per year, and the company is commissioning its first commercial plant for 2025.

"Sublime is on course to make CO₂-free cement that performs better and costs less than what pours out of concrete trucks today," said Clay Dumas, general partner at Lowercarbon Capital. "Now, the ASTM C1157 designation paves the way for global adoption of the world's cleanest cement."

It is estimated that 70% of the infrastructure that will exist in 2050 to shelter the world’s growing urban population remains unbuilt. To balance such global construction goals with emissions reductions targets means a low-carbon approach like Sublime's becomes essential to not only meet this demand but also surpass the performance of current standards. It is critical to gain the confidence of the entire ecosystem of buyers in next-generation cement, spanning ready-mix concrete suppliers, concrete contractors, architects, engineers, general contractors, building owners, and government agencies. Sublime is in discussions with customers across these constituencies and is actively planning for its first field pours in Q4 2023.

"The global construction industry understands the importance of decarbonization of cement and concrete but has to balance this with the responsibility of executing large infrastructure projects that satisfy current specifications and maintain durability requirements," said Jim Carreira, technical director at Boston Sand and Gravel. "Sublime's ASTM C1157 compliance is an important step in increasing the industry's confidence in shifting towards a drastically decarbonized material that performs like the material our industry currently relies on."

“Thoughtful owners, designers, and contractors have long recognized that performance-oriented specifications asking for what is needed, instead of telling the suppliers what to do, result in the better value solutions,” said Don Davies, a structural engineering leader with projects in 18 countries and more than 50 major metropolitan centers. “With proper testing and data back-up, we have long seen ASTM C595 and the fully performance-oriented ASTM C1157 cements as the low carbon keys to our future. I am personally excited with how these next-generation materials, like the C1157 Sublime Cement™, will more rapidly slash emissions in concrete.”

Sublime continues to add to its coalition of partners ready and willing to adopt low-carbon cements and decarbonize their supply chains. To learn about partnership opportunities for integrating Sublime Cement™ into your projects, connect with our team at partnerships@sublime-systems.com.

About Sublime Systems

Sublime Systems is on a mission to have a swift and massive impact on global CO₂ emissions with a breakthrough process that can manufacture cement without fossil fuels or limestone. Sublime replaces the industry’s legacy kilns with an electrochemical process that makes cement at ambient temperature, extracting calcium and silicates from an abundance of raw materials to make cement. This novel approach bypasses both CO₂ process emissions and heating emissions, without the need for post-combustion carbon capture, producing ASTM C1157-compliant Sublime Cement™ as a drop-in replacement for ordinary portland cement in concrete. Sublime was founded at MIT by Leah Ellis, PhD, and Prof. Yet-Ming Chiang, both respected experts in materials science, electrochemical systems, and sustainability research. The company has raised more than $50M from a leading consortium of climate tech investors, ARPA-E funding, and strategic investor Siam Cement Group, the largest cement producer in Southeast Asia. It currently operates a pilot plant with a >100-tonnes-per-year production capacity. Learn more at sublime-systems.com.

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"Data-driven performance-based standards, like ASTM C1157, allow us to solve the right problems: safety and carbon avoidance, rather than adherence to a legacy recipe," said Sublime Systems Co-Founder and CEO Leah Ellis, PhD.