July 21, 2023

Seattle building is the first to get new cement-free concrete

Photos from C-Crete Technologies [enlarge]

Bright Street Construction used the cement-free concrete to create shear walls in the Green Lake building.

The first batch of a new concrete that doesn't use cement was recently poured as part of a seismic retrofit to a 120-year-old brick building in the Green Lake neighborhood. That two-story building at 7200 Woodlawn Ave. N.E. is owned by Donald Davies and will be the future home to Atlantic Crossing Pub, which is moving from the Roosevelt neighborhood.

The 60 or so tons of cement-free concrete used for the project was concocted by San Leandro, California-based C-Crete Technologies and delivered by Heidelberg Materials. The material was poured in foundations and shear walls.

“As a developer, a structural engineer of 33 years, and a leader in low-carbon construction, I'm seeing many lower-carbon concretes being discussed,” Davies says in a news release. “I'm seeing exciting advancements, but few are ready to scale into production the way C-Crete can now. No-cement and low-carbon concrete isn't just a pipe dream. It is real, it is now, and it works. This project proves it's possible, today.”

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The concrete had great flowability and achieved a loading strength of over 5,000 psi.

C-Crete Technologies claims its product produces almost no carbon dioxide in the manufacturing process and actually absorbs it over time. The company touts the new material as a “drop-in replacement” for Portland cement, which it says causes about 7% of total CO2 emissions worldwide. Each ton of C-Crete binder that replaces Portland cement prevents about 1 ton of CO2 emissions, according to the company.

C-Crete Technologies says the material has “cost parity” with Portland cement. The news release states the product uses a suite of natural minerals and industrial by-products, ensuring an abundant feedstock.

Rouzbeh Savary, C-Crete Technologies founder and president, tells the DJC that C-Crete is a pozzolanic material but didn't elaborate further on its full composition, other than disclosing there is no fly ash in the mix.

For the Green Lake project, C-Crete Technologies reports that the concrete had great flowability and achieved a loading strength of over 5,000 pounds per square inch, greater than the ASTM standard of about 4,000 psi for most residential, commercial and infrastructure concrete applications. The company also claims the product meets other key industry standards, shows outstanding durability — such as resistance to freeze-thaw cycles, alkali-silica reactions, and chloride and acid penetrations — and is compatible with conventional concrete admixtures.

Davies co-owns the building with Joan Crooks. The project team includes Upward Architecture and Bright Street Construction.

According to Davies' Linkedin profile, he co-founded Davies-Crooks Associates in February after working at Magnusson Klemencic Associates for nearly 34 years, exiting that engineering firm as president. He is also chair of Building Transparency, a nonprofit helping the building industry address embodied carbon's role in climate change.

Savary says the building should be finished in the first or second quarter of 2024. He says Atlantic Crossing Pub will be on the first floor and Davies-Crooks Associates on the second.

What's next for C-Crete Technologies? The company says it wants to collaborate with architects, designers, general contractors, ready-mix companies, building owners and decision-makers for infrastructure projects to accelerate the product's adoption.

“Given that our product meets industry standards and has cost-parity with conventional concrete, it opens up an entirely new era in construction,” Savary says.