CarbonCure’s technology is an affordable retrofit to existing concrete plants that allows producers to recycle waste carbon dioxide (CO2) during production to make more environmentally friendly concrete.
Carbon dioxide is captured from the emissions of local industrial polluters by gas suppliers across the country. This purified and liquefied CO2 is delivered to CarbonCure’s concrete producer partner’s plants in pressurized tanks. The CarbonCure technology precisely injects the recycled CO2 into wet concrete while it’s being mixed. Once injected, the CO2 becomes chemically converted into a solid mineral and permanently captured within the concrete. The technology is integrated with the producer’s batching system and has no impact on normal operations, which means that CarbonCure’s customers can continue to supply the same high quality concrete products – only now they’re greener!
The CO2 tank (right) sits near the concrete mixer. CarbonCure’s proprietary technology precisely injects the CO2 into wet concrete while it’s being mixed.
When CO2 is added to the concrete during mixing, the CO2 reacts with water to form carbonate ions. The carbonate then quickly reacts with calcium ions released from the cement to rapidly form nano-size calcium carbonate (limestone) minerals. The conversion of CO2 into solid calcium carbonate minerals means that the CO2 has become permanently bound within the concrete and will never be released back into the atmosphere.
Nano-materials, in the form of extremely fine particles, are known to enhance the material properties of concrete but their use has been limited by production, process integration and cost barriers. The CarbonCure technology enables concrete producers to form well-dispersed nano-materials within their concrete in a practical and affordable way.
Illustration showing the formation of calcium carbonate nanoparticles resulting from the addition of carbon dioxide to fresh concrete.
The nano sized calcium carbonate minerals act as a nucleation site for the hydration reaction that gives concrete its strength. Ready mixed concrete producers see an average strength improvement of approximately 10% when comparing concrete injected with CO2 to the control. Masonry concrete producers see a neutral to positive affect on compressive strength. The improvement to compressive strength enables ready mixed concrete producers to optimize their mix design, which typically includes reducing cement content. On average, CarbonCure ready mixed concrete producer customers are able to reduce cement by 5-8% and maintain the original compressive strength, without affecting the concrete’s fresh properties.
The production of cement creates about 5% of the world’s CO2 greenhouse gas emissions. The ability to reduce cement prevents additional CO2 from being produced. The concrete and cement industry is one of a select few materials in the world that has the unique ability to convert CO2 into a new product. When CO2 is introduced to concrete, it converts to a mineral and will never escape back into our atmosphere – because it no longer exists! Now, CO2 can be used to make better products!
Do you have a question about the science behind CarbonCure’s technology? Contact us!