World’s First Basalt-Based Cement-free Concrete at Hubbard’s Corner

March 2024, Seattle, WA

March 2024, as part of the continuing series of successful cement-free pours at the Hubbard’s Corner site in Seattle, WA, C-Crete successfully poured the world’s first basalt-based, cement-free concrete – a near zero-emission product completely free of Portland cement. The historic pour involved approximately 20 tons of material placed in an outdoor slab-on-grade foundation at 7200 Woodlawn in Seattle.

The application supported a loading dock stem wall and partial ramp replacement at Hubbard’s Cornersite. With this milestone, the total volume of C-Crete concrete used at the site reached 140 tons, each mix leveraging distinct cement-free binders such as zeolite and basalt. Basalt – a non-carbonate rock primarily composed of silicon, aluminum, and calcium – was chosen as the primary binder due to its natural abundance, especially compared to limestone traditionally used in Portland cement production.

In contrast to Portland cement, which contributes roughly 8% of global CO₂ emissions due to high-temperature calcination of carbonate rock, C-Crete’s basalt-based binder eliminates such emissions and even allows CO₂ uptake during curing, offering significant carbon savings.

The basalt-based concrete delivered compressive strength exceeding 5,000 psi at 28 days, which outperforms the strength, setting time, pumpability, and surface finish of conventional concrete. It also meets/exceeds ASTM C1157 and other durability standards, with third-party verification supporting its technical and environmental features.

This innovation further underscores C-Crete’s growing portfolio of cement-free concretes, each engineered with abundant regional feedstocks and designed to replace carbon-intensive binders without sacrificing performance or increasing cost. Basalt and zeolite – each available at least at the order of several billion/trillion tons – are only few representative feedstocks in C-Crete’s portfolio of cement-free concretes.

C-Crete extends its gratitude to the dedicated team behind the pour at the Hubbard’s Corner project in Seattle, including:

  • Building Transparency,
  • Don Davies,
  • Allan Paull,
  • Larry Busch,
  • John Cherne,
  • Martin Josund

To learn more about this project: Click HERE