Low-carbon cement without compromise

A one-for-one replacement for ordinary Portland cement (OPC)

Sublime Cement, produced by our post-carbon process, adheres to strict industry-accepted standards. 

This highly engineered, low-carbon cement has similar (or better!) ultimate strength, durability, slump, and set time as the cement we use today for our buildings and infrastructure. 

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Our ASTM C1157-compliant cement will be the first to commercial scale that approaches “true-zero” carbon — rather than just “net-zero” — by avoiding CO₂ emissions in the first place and foregoing the need for carbon capture and storage.

1:1

The needs of the construction ecosystem are at the center of our work. Sublime CementTM is a drop-in replacement for today’s portland cement, creating a frictionless replacement for ready-mix concrete producers that meets or exceeds ASTM C1157 standards.

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Sublime Cement™ manufacturing doesn’t emit CO₂ that then needs to be cleaned up with expensive, complex carbon capture and storage (CCS) infrastructure. Because we replace the kiln, we can ultimately scale down the cost to match the kiln, without reliance on carbon credits. 

We are developing the least expensive, most decarbonized cement

CO₂ Impact

Avoids fossil fuels

Drop-in replacement 

for OPC in most applications

Cost parity

at scale

Scalability

% of global supply potential

Sublime Cement™

Cement today (OPC)

OPC + Carbon Capture

Supplementary Cementitious Materials

Carbonated / CO₂-Cured

 
Ideal
 
Suboptimal
 
Insufficient

Sublime CementTM

CO₂ Impact

Ideal
 

Drop-in Replacement

for OPC in most applications

Ideal
 

Scalability

% of global supply potential

Ideal
 

Avoids fossil fuels

Ideal
 

Cost Parity

at scale

Ideal
 

Cement today (OPC)

CO₂ Impact

Insufficient
 

Drop-in Replacement

for OPC in most applications

Ideal
 

Scalability

% of global supply potential

Ideal
 

Avoids fossil fuels

Insufficient
 

Cost Parity

at scale

Ideal
 

OPC + Carbon Capture

CO₂ Impact

Ideal
 

Drop-in Replacement

for OPC in most applications

Ideal
 

Scalability

% of global supply potential

Suboptimal
 

Avoids fossil fuels

Insufficient
 

Cost Parity

at scale

Insufficient
 

Supplementary Cementitious Materials

CO₂ Impact

Suboptimal
 

Drop-in Replacement

for OPC in most applications

Ideal
 

Scalability

% of global supply potential

Suboptimal
 

Avoids fossil fuels

Suboptimal
 

Cost Parity

at scale

Ideal
 

Carbonated / CO₂-Cured

CO₂ Impact

Suboptimal
 

Drop-in Replacement

for OPC in most applications

Suboptimal
 

Scalability

% of global supply potential

Suboptimal
 

Avoids fossil fuels

Insufficient
 

Cost Parity

at scale

Ideal
 

Sublime Cement™  meets or exceeds the strength and durability of traditional cement

Sublime Cement™  delivers across key durability characteristics

DURABILITY TEST
RELATIVE PRFORMANCE TO OPC

Alkali-Silica Reaction (ASTM C1260/C1239, AASHTO T380)

 
Much Better

Rapid Chloride Permeability Test (RCPT) (ASTM C1202)

 
Much Better

Electrical Surface Resistivity (AASHTO T358)

 
Better

Drying Shrinkage of Concrete (ASTM C157)

 
Better

Sulfate Attack (ASTM C1012)

 
Better

Freeze-thaw resistance (ASTM C666)

 
Equivalent

Sublime Cement™  28-day strength outperforms that of Massachusetts regional benchmark mixes

Low carbon,
low friction

Third party validations ensure our performance, safety, and emissions reduction impact.

American Engineering Testing ensured our product meets ASTM C1157, the standard performance specification for hydraulic cement.

Our Safety Data Sheets ensure our product complies with OSHA’s Hazard Communication Standard 29CFR1910.1200 and can be safely handled just like the cement the world is used to.

Climate Earth completed our screening life cycle assessment (LCA), validating our process’ path to a >90% reduction in cement’s global warming potential.

We are thoughtfully validating our product in partnership with the construction industry

The global construction industry is rightfully mindful of safety and cautious about new materials. We’ve developed a comprehensive validation process — that starts in our lab and ends in the field — to earn their trust. 

Our technology is
lab and field ready

Here’s how we got there

Characterization of materials

Calorimetry tests heat of hydration, indicators of early-age behavior and strength development. 

Mortar & micro-concrete

We test for flowability, compressive strength, and admixture compatibility.

Concrete

We test for the concrete’s fresh and hardened durability properties.

Third-party validation

External, ASTM-validated labs test our material across strength and durability parameters.

Ready-mix lab trials

Local ready-mix partners test our cement’s performance in their concrete mixes.

Small-batch field trials

We ensure our material can mix and pour out of a truck and set and finish when placed by concrete contractors.

Field pours

This all leads up to field construction projects, where our material is mixed at the batching plant, transported in ready-mix trucks, pumped, placed, and finished into a final hardened concrete slab.






Mortar & micro-concrete

We test for flowability, compressive strength, and admixture compatibility.

Third party validation

External, ASTM-validated labs test our material across strength and durability parameters.

Small-batch field trials

We ensure our material can mix and pour out of a truck and set and finish when placed by concrete contractors.

Our technology is
lab and field ready

Here’s how we got there

Characterization of materials

Calorimetry tests heat of hydration, indicators of early-age behavior and strength development. 

Mortar & micro-concrete

We test for flowability, compressive strength, and admixture compatibility.

Concrete

We test for the concrete’s fresh and hardened durability properties.

Third-party validation

External, ASTM-validated labs test our material across strength and durability parameters.

Ready-mix lab trials

Local ready-mix partners test our cement’s performance in their concrete mixes.

Small-batch field trials

We ensure our material can mix and pour out of a truck and set and finish when placed by concrete contractors.

Field pours

This all leads up to field construction projects, where our material is mixed at the batching plant, transported in ready-mix trucks, pumped, placed, and finished into a final hardened concrete slab.







Mortar & micro-concrete

We test for flowability, compressive strength, and admixture compatibility.

Third party validation

External, ASTM-validated labs test our material across strength and durability parameters.

Small-batch field trials

We ensure our material can mix and pour out of a truck and set and finish when placed by concrete contractors.

Our technology is lab and field ready

Here’s how we got there

Characterization of materials

We replace carbon-intensive limestone with calcium silicate minerals or industry wastes

Concrete

We test for the concrete’s fresh and hardened durability properties.

Ready-Mix Lab Trials

Local ready-mix partners test our cement’s performance in their concrete mixes.

Field pour

This all leads up to field construction projects, where our material is mixed at the batching plant, transported in ready-mix trucks, pumped, placed, and finished into a final hardened concrete slab.

Mortar & Micro-Concrete

We test for flowability, compressive strength, and admixture compatibility.

Third party validation

External, ASTM-validated labs test our material across strength and durability parameters.

Small-batch Field Trials

We ensure our material can mix and pour out of a truck and set and finish when placed by concrete contractors.

Our technology is lab and field ready

Here’s how we got there

Characterization of materials

We replace carbon-intensive limestone with calcium silicate minerals or industry wastes

Concrete

We test for the concrete’s fresh and hardened durability properties.

Ready-Mix Lab Trials

Local ready-mix partners test our cement’s performance in their concrete mixes.

Field pour

This all leads up to field construction projects, where our material is mixed at the batching plant, transported in ready-mix trucks, pumped, placed, and finished into a final hardened concrete slab.

Mortar & Micro-Concrete

We test for flowability, compressive strength, and admixture compatibility.

Third party validation

External, ASTM-validated labs test our material across strength and durability parameters.

Small-batch Field Trials

We ensure our material can mix and pour out of a truck and set and finish when placed by concrete contractors.

Create the post-carbon future, today.

Cement is a high-emitting material but a small fraction of a building’s final cost. Replacing OPC with Sublime Cement™  is a cost-effective solution for reducing the embodied carbon of your infrastructure.

We produce Sublime Cement™  out of our 250TPY pilot facility in Somerville, MA but are building our first commercial kiloton facility to open in Holyoke, MA as early as 2026. Inquire about partnering today around a testing deployment or reserving Sublime Cement™  produced out of Holyoke.   

Get Sublime Cement™ 
for your low-carbon construction project

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