Prometheus Materials ProZERO Carbon-Negative Cement Blend

Prometheus Materials, Inc. is a US company based in Longmont, Colorado, co-founded by CEO Loren Burnett, that develops and produces low-carbon and carbon-negative cement technologies for the construction industry. It tackles the emissions from mining limestone and firing it in kilns by growing the mineral biologically instead.

Microalgae are grown in open raceway ponds, where they capture carbon and form biogenic limestone through biomineralisation; the sun-dried biomineral is combined with a proprietary constituent blend to make ProZERO. ProZERO replaces a portion of portland cement one-to-one and can also substitute part of fly ash or slag, working in standard ready-mix plants without equipment or workflow changes. It is supplied in bags, super sacks or bulk trailers to ready-mix producers, precast and concrete masonry unit makers, contractors and developers.

• Algae biomineralisation: microalgae in raceway ponds convert captured carbon into biogenic limestone.
• No kiln or quarry: avoids limestone mining and high-temperature calcination.
• One-to-one replacement: ProZERO substitutes part of portland cement or of fly ash and slag.
• Ready-mix and precast lines: products for ready-mix concrete and carbon-negative precast and CMUs.
• Standards and LCA: claims compliance with ASTM C90, C129, C1157 and E84 with third-party LCA stages A1-A3.
• Flexible delivery: bags, super sacks and bulk trailers shipped FOB Longmont, Colorado.

Ready-mix suppliers for data centre and hyperscale projects in Vietnam can test ProZERO at 10 to 40% replacement to meet client carbon targets. Precast and block manufacturers can develop lower-carbon masonry units for green-certified buildings. Aquaculture or algae producers could explore a partnership to supply biomineral feedstock regionally.

ProZERO typically replaces 10 to 40% of cementitious content in ready-mix, and a Maryland data centre pour of over 300 cubic yards at 20% replacement achieved an estimated 45% GWP reduction versus 100% OPC. Concrete strengths range from 150 psi flowable fill up to 6,000 psi. Producers keep existing mix designs and plant equipment, and stored carbon is locked into the finished building product.

Data centre operators, general contractors and developers are setting embodied carbon targets for concrete, creating demand for drop-in cement replacements that work with existing mix designs. As fly ash and slag supply tightens in some markets, bio-based SCM alternatives are gaining interest, and Southeast Asia's tropical climate is suited to algae cultivation.

Based in Longmont, Colorado; Loren Burnett is President, CEO and co-founder. In May 2026 Green Stream Algae became its exclusive algae and biomineral supplier in the Americas and an investor. Project partners named on its site include SOM, Skanska, Mortenson, Turner, Cemex, Basalite and CU Boulder. An EPD is not yet available.