Buildings that lock away carbon

How far are we from building materials that store significant carbon at scale?

Some building materials now contain biochar, or take up carbon dioxide while they cure. Coffee biochar concrete has been placed on real construction work in Victoria, Australia, and carbonation-cured bendable concrete slabs were installed in a sidewalk in Michigan and were reported intact after 34 months in service. The sources reviewed do not give an independently verified tonne figure for carbon stored in a building product at scale. The European standard used for product carbon declarations is reported not to credit long-term storage of biogenic carbon, and that treatment is disputed.

AI illustration · Illustrative scene, not a photograph of the specific device or experiment.
WHERE WE AREPilots

Close. Early pilots are running in the real world.

Biochar concrete has reached a real construction trial, and carbonation-cured concrete has a pilot-scale installation reported in a peer-reviewed study. The sources reviewed do not verify the tonnes of carbon stored. No building or product standard reviewed credits stored carbon in a structural product. Those facts fit a pilot stage rather than scaling or widespread use.

The tech tree

Everything recorded on Vrulum that this future needs, oldest foundations at the top and the goal at the bottom. Lines show what each step requires.

What it takes: Buildings that lock away carbon Unlocked Being researched Locked
  1. 2010BiocharCommercial Unlocked.
  2. 2023Carbon-storing building materialsPilot and early commercial Unlocked.
  1. 2025Biochar concrete placed on a real construction projectDone Unlocked.
  2. 2025Carbonation-cured concrete in a pilot sidewalk installationDone Unlocked.
  3. Date not recordedIndependently verified tonnes of carbon stored by a product at commercial scaleIn progress Being researched.
  4. Date not recordedProduct carbon accounting that credits long-term storageNot started Locked.
  5. Date not recordedBuilding code or standard acceptance for structural useNot started Locked.
  6. Date not recordedLong-term durability and end-of-life carbon fate measured in the fieldIn progress Being researched.
  1. GoalBuildings that lock away carbonGoalRequires: Carbon-storing building materials, Biochar, Biochar concrete placed on a real construction project, Carbonation-cured concrete in a pilot sidewalk installation, Independently verified tonnes of carbon stored by a product at commercial scale, Product carbon accounting that credits long-term storage, Building code or standard acceptance for structural use, Long-term durability and end-of-life carbon fate measured in the field. Locked.

The road so far

2 of 6 steps done, 2 in progress.

  1. Done · 2025Biochar concrete placed on a real construction project

    A peer-reviewed field study reports coffee biochar concrete made and placed in Victoria, Australia, and compared with a control mix. The lab recipe used a 350°C pyrolysis step, but the equipment used for the field trial could not reach that temperature, so the field biochar was made under different conditions. Press coverage describes a later trial at 400°C. The authors describe the field work as a translation step. The study does not establish long-term durability in other climates or structural uses. [1][3]

  2. Done · 2025Carbonation-cured concrete in a pilot sidewalk installation

    A pilot-scale study reports bendable concrete slabs, cured with CO2, installed in a sidewalk renovation in southeast Michigan. The publisher abstract reports that the slabs were intact after 34 months in service. The authors list open questions about whether CO2 storage and emissions reductions hold at different scales and over longer periods. [2]

  3. In progressIndependently verified tonnes of carbon stored by a product at commercial scale

    The sources reviewed did not include an independent verification of tonnes stored, or a published method that links tonnes to a named product. Stored carbon per cubic metre of a named product has not been verified in the sources reviewed.

  4. Not startedProduct carbon accounting that credits long-term storage

    Ecochain's guide to EPDs explains that biogenic carbon taken up during production is treated as emitted or transferred to nature at end of life. It does not say directly whether storage duration earns a credit. Biochar Europe's open letter asks for a targeted revision of EN 15804 so that permanent removals are separated from temporary biogenic storage and credited, with independent third-party audit. The sources give no date for any revision. [4][5]

  5. Not startedBuilding code or standard acceptance for structural use

    The sources reviewed do not show a building code or product standard that accepts biochar concrete or CO2-cured concrete for structural use on the basis of stored carbon. Acceptance for specific applications could not be confirmed from the sources reviewed.

  6. In progressLong-term durability and end-of-life carbon fate measured in the field

    Multi-year monitoring is under way for at least one pilot slab. Results across different climates, structural forms, demolition, crushing and reuse are not yet reported in the sources reviewed. [2]

Why it matters

Cement and concrete are used in very large quantities, so a material that keeps carbon out of the atmosphere for decades could change the climate footprint of buildings. It could also link construction to waste streams such as crop residues and industrial by-products. Whether this counts as storage depends on how long the carbon stays locked in and on how product carbon rules treat it.

What stands in the way

  • Biochar made at production scale does not yet match the lab recipe. The field work used a different pyrolysis temperature from the one that worked in the lab.
  • Biochar properties depend on feedstock and production conditions, so results from one feedstock do not carry over to others without testing.
  • CO2 curing needs a CO2 source, purification, transport and energy. The net amount stored depends on all of these inputs.
  • The European product carbon standard is reported not to credit long-term storage of biogenic carbon, so product declarations may not show permanent storage under the current rules.
  • Durability evidence is limited to a small number of field sites and years. Freeze-thaw, salt, corrosion and fire performance over long service lives are not yet reported.
  • Carbon retained through demolition, crushing and reuse has not been measured for these products in the field.

Signals to watch

  • A revision of EN 15804 or an equivalent product standard that credits permanent carbon removal in durable products, with audit rules.
  • Independently verified tonnes of CO2 stored per unit of a named product, published with the method used.
  • Multi-year monitoring results from the Michigan slabs and the Victorian construction work.
  • A building code or product standard that accepts stored carbon or CO2-cured concrete for structural use.
  • Biochar produced at production scale to a repeatable specification that matches the lab processing conditions.

Sources

  1. peer reviewed paper
    Translating lab success to the field: Evaluating coffee biochar-enhanced concrete in real-world construction
    Rajeev Roychand, Shannon Kilmartin-Lynch, Mohammad Saberian et al.. Case Studies in Construction Materials, Jul 2025.
  2. peer reviewed paper
    Pilot-scale validation of CO2 utilization for greener and tougher infrastructure through carbonation curing of bendable concrete
    Duo Zhang, Bing Feng, Beata Jaworska et al.. Journal of Cleaner Production, Feb 2025.
  3. news
    Coffee biochar used to strengthen concrete in construction
    Megan Breen. CreateDigital, 13 Mar 2025.
  4. other
    Biogenic Carbon in EPDs: A Guide for Manufacturers
    Sai. Ecochain, 26 Nov 2025.
  5. other
    Reforming EN 15804 to Accurately Credit Biochar-Based Permanent Carbon Removals
    German Biochar e.V. (republishing a Biochar Europe open letter), 10 Sept 2026.

Last reviewed 21 Oct 2026.