Honolulu’s Concrete Mineralization Resolution, Explained
Specs in Honolulu increasingly ask for carbon‑mineralized concrete. If your mixes are ready but your documentation lags, competitors with product‑specific EPDs will look simpler to select. Here is what the City’s resolution actually says, how Hawaii state rules stack on top, and the quickest path to publish credible EPDs without hijacking your R&D or plant teams for months.
What Honolulu actually adopted
Honolulu’s City Council approved Resolution 18‑283 urging the City to consider carbon dioxide mineralized concrete for all future City infrastructure where it does not significantly increase cost or delay. It is a signal to specifiers, not a mandate, and it invites the budget office to explore incentives.
The state layer that makes it real
Since July 1, 2020, designs for new Hawaii state buildings must use post‑industrial CO2 mineralized concrete where cost‑effective, which means project teams routinely ask producers to show proof in submittals (Hawaii Legislature HB1846, 2020) (Hawaii Legislature HB1846, 2020).
What “CO2 mineralized” means on your mix sheet
Mineralization injects measured CO2 during mixing, where it reacts and becomes solid calcium carbonate within the concrete. Done correctly, it can enable slight cement reductions at equal strength. The chemistry is permanent, so owners want it documented, not just promised.
Where the numbers come from
In a 2019 DOT pilot on Oʻahu, the agency reported potential embodied‑carbon reductions of about 25 pounds CO2 per cubic yard depending on final specs, using locally supplied CO2 with side‑by‑side test pours (HDOT, 2019) (HDOT, 2019). Your reductions will vary by cement content, SCMs, and the mineralization dose.
Why EPDs matter under Honolulu’s policy
The resolution asks agencies to consider mineralized concrete, which immediately raises the next question on submittals, how much embodied carbon did it actually cut. A third‑party verified, product‑specific EPD answers that in one page and reduces the risk that an owner applies a conservative default that makes your mix look worse than it is.
How to reflect mineralization correctly in an LCA
Model the CO2 injection step as an input with metered dose per cubic yard, show cement reduction if achieved at equal performance, and keep plant utilities and admixture data tied to a clear reference year. Be explicit about system boundaries, allocation, and whether any clinker reduction came from SCMs, limestone cements, or both. Auditors look for reproducible metering logs.
PCRs and program operators, in plain English
Pick the concrete PCR that your main competitors use, then verify the publication window and reviewer requirements. That keeps comparability strong and avoids do‑overs when you renew. U.S. program operators commonly used by concrete producers accept plant‑specific data and publish on widely searched portals, which is what your specifiers actually see.
Documentation you will need, nothing more
Have these at hand before kickoff. Cement and SCM consumption by mix, plant‑level energy and water for the reference year, CO2 source and purity, mineralization dose logs, mix performance data, and shipping distances. A good partner will handle collection and QA with your QA/QC lead so batching crews dont get bogged down.
Procurement reality in Honolulu
City buyers can ask for mineralized concrete under 18‑283, yet still pick the lowest‑risk submittal. When two bids look similar on price and schedule, the mix with a recent EPD that quantifies CO2 savings tends to feel safer to approve. That is the silent advantage your sales team needs when timelines are tight.
Fast track without cutting corners
Clarify the reference year, confirm the target PCR, align on the publishing operator, then lock the data request to exactly those fields. Keep verification and publishing in one run so you are not waiting on handoffs. The right workflow turns EPDs from a slog into a repeatable submittal asset across your mix families.
Where this heads next
LEED v5 drafts keep turning the screws on embodied carbon performance, and public owners in Hawaii are already asking for quantified reductions, not claims. If your Honolulu mixes can show mineralization benefits with clean EPDs, you smooth approvals today and build share where carbon accounting is becoming routine.
One more number worth tracking
When you report reductions, keep the unit consistent with what owners expect on Oʻahu. Pounds CO2 per cubic yard works well locally because it matches prior DOT communications and jobsite reality, then convert to kilograms per cubic meter when engineers ask for SI units (HDOT, 2019) (HDOT, 2019).
Frequently Asked Questions
Does the Honolulu resolution mandate carbon-mineralized concrete on every City job?
No. It urges City agencies to consider mineralized concrete where it does not significantly increase cost or delay, and invites exploration of incentives.
Do Hawaii state building projects actually require mineralized concrete?
For new state buildings, designs since July 1, 2020 must use post‑industrial CO2 mineralized concrete where cost‑effective (Hawaii Legislature HB1846, 2020) (HB1846, 2020).
What number should we claim for carbon savings?
There is no single number. HDOT’s pilot cited about 25 lb CO2 per cubic yard depending on specs, but your actual reduction must be measured from your dose, cement content, SCMs, and verified in a product‑specific EPD (HDOT, 2019) (HDOT, 2019).
Which EPD program operator should we use?
Choose one that aligns with your PCR and your customers’ expectations. The priority is fast, clean data collection, credible third‑party review, and publication where specifiers actually look.
About the Author
With a passion for sustainability and a love for complex data, Toby helps manufacturers efficiently collect data from across their organization and get their EPDs done right. He’s especially interested in how AI can support human expertise, helping R&D and factory teams work faster, smarter, and with less friction.
