Solidia Technologies, a New Jersey-based company that produces sustainable construction products, has announced test results from a new concrete mixture that consumes carbon dioxide during the curing process, reducing the manufacturing process's carbon footprint while producing high-performance products with the same raw materials and equipment as traditional concretes.

Test results released by Solidia Technologies on February 19 show that curing concrete with carbon dioxide instead of water can reduce the carbon footprint of cement and concrete up to 70 percent, while producing higher-performing concrete products.

Solidia Cement, the key to the new concrete technology, is primarily composed of low-lime and contains calcium silicate phases, which react with gaseous carbon dioxide (CO₂) in the presence of moisture. During the carbonation curing process, calcite (CaCO3) and silica gel (SiO2) are formed to develop strength within the concrete. This is in contrast to the hydration process occurring in Portland cement-based concrete, which involves a hydration reaction between high-lime calcium silicate phases and water to form calcium-silicate-hydrate gel and calcium hydroxide.

The proprietary concrete contains the same raw materials as ordinary Portland cement, namely, fine and coarse aggregate, supplementary cementitious materials and chemical admixtures. Mixing and forming processes are the same as those used in OPC-based concrete production.

The new curing process sequesters up to 300 kg of CO₂ per ton of cement used. When the reduced CO₂ emissions associated with production are considered with the cement's capacity to sequester CO₂ during curing, the CO₂ footprint created by the cement's manufacture and use can be reduced by up to 70 percent compared to traditional Portland cement.

The white paper was co-authored by Solidia Technologies' senior research scientist Jitendra Jain, Ph.D., research scientist Omkar Deo, Ph.D., principal scientist Sada Sahu, Ph.D., and chief technology officer Nicholas DeCristofaro, Ph.D.

"For over 50 years, scientists have tried to cure concrete with CO₂ knowing the resulting product would be stronger and more stable. By making our technology affordable and easy to adopt, Solidia Technologies has advanced the commercial viability of CO₂-cured cement and concrete," Dr. DeCristofaro said. "Our current focus is testing additional applications with an even wider variety of concrete formulations and manufacture methods to facilitate adoption across the globe."