Reducing emissions with CO² cured-concrete

A new cement block manufacturing process developed by an American company named Solidia Technologies® produces 40% fewer emissions during manufacturing than conventional concrete, resulting in a dramatically lower environmental footprint. Solidia’s concrete is formulated with less lime and is cured at lower temperatures than similar products - 1250° C kiln temperature compared to the usual 1450° C.

Normal concrete production consumes an equal amount of water to solid material, which is necessary for the chemical reaction that causes the binders to react. Solidia concrete instead uses CO² captured from the combustion fumes at the industrial production site, which is then re-injected into the mix. That CO² is sequestered permanently in the material instead of being released into the atmosphere.

The cement reacts with carbon dioxide to form calcium carbonate (CaCo³) and calcium silicate (CaSiO³), which acts to harden the blocks. The reaction occurs in a closed chamber at a moderate temperature (60° C or lower) and at ambient pressure. Solidia’s concrete also hardens in less than 24 hours compared to conventional concrete, which takes several days to sufficiently harden.

The end result is a 70% reduction in the total ecological footprint of conventional concrete, including 60 to 80% less water consumed. And what gives this product a huge advantage in the marketplace is that with lower material production temperatures, the manufacturing costs are actually lower.

Just 30 Solidia Concrete blocks will absorb 22 kg of CO² during the production phase (240 kg of CO² per 1000 kg of cement), which is equivalent to the absorption of a single tree in one year. (And talking of Trees, if you're more inclined to build or maintain a wooden deck, check out our 10 tips for building a green wooden deck here)

Other advantages:

• Reduced efflorescence as it is less porous, and absorbs less water than normal concrete
• Stronger and more abrasive resistant than standard concrete
• Improved durability: more resistant to cracking due to the freeze/thaw cycle
• Compatible with unconventional aggregates and recycled glass

Don’t get your hopes up yet that you will be able to pour a basement or concrete slab with this; it must be cured in the factory, so its applications will be limited to paver stones and formed blocks.

Solidia Technologies® holds the exclusive rights to license the patent, although Lafarge has signed an agreement with Solidia in 2013 to market the product in North America and Europe. In a recent development, Patio Drummond in Quebec has started production of carbon-negative concrete CMU blocks for the North East of Canada and USA - see here. Prometheus is another American company that has developed a new zero-carbon concrete technology with microalgae.