Infused Cement Technology...Slag, Clinkers, Fly Ash & Carbon Dioxide
When we think of the word infused, most Americans would picture a turkey broiling in the oven, a steak on the grill or a mason jar full of fruit and water. For most people, cement would not spring to mind.
As a precast concrete producer, you have seen countless articles on carbon reduction initiatives within the industry. In 2013, the NPCA outlined goals to reduce CO2 emissions 10% by 2020. The purpose of this content is to inform and is not an endorsement of any technology.
According to published reports, the concrete industry is thought to emit from five to eight percent of total world carbon emissions. The two primary emission generation sources include heating of the kiln, which consumes fossil fuels. The second source is the chemical reaction – making cement out of calcium carbonate.
LafargeHolcim, a Swiss multi-national company, and also the largest cement manufacturer in the world has announced that they have partnered with Solidia Technologies to bring carbon-reducing precast concrete production capabilities to the United States.
According to their press release:
The product is the result of a six-year collaboration between LaFargeHolcim and Solidia and uses a special binder — produced at lower temperatures — and a patented curing process that uses CO2 rather than water. By adding and absorbing CO2, Solidia Concrete reaches strength in less than 24 hours unlike precast concrete made with Portland cement, which takes 28 days to reach strength.
Below is a diagram outlining the Solidia process.
CarbonCure, based in Canada, has also invented a system for making concrete that traps CO2 emissions. Their process captures CO2 and injects it into concrete as it is mixed. Once the concrete hardens, the carbon is isolated forever, as it reacts with the concrete and becomes a mineral. If the building is razed in the future, the concrete rubble remains carbon neutral. Below is a diagram outlining the CarbonCure process.
Geopolymer Cement is also an eco-sustainable process made from waste materials fly ash and slag. Fly ash is a byproduct from burning pulverized coal in electric power generating plants and slag is a glass-like by-product left over from raw ore in the steel manufacturing process. The geopolymer end product is both environmentally friendly, with excellent compression strength. Unfortunately, due to the caustic nature of the chemicals used as an activator, only skilled and trained individuals are recommended in the mixing process. So far, safety concerns and more robust technologies have inhibited this technique from advancing as an industry norm.
It has been said, “Technology is much like a city bus. You either hop on or it leaves without you.” This may be true, but it is prudent to check the schedule beforehand to make sure the intended destination is reached. To date, only 10% of the industry has implemented zero carbon technology. Beyond sustainability, there is much to learn in regards to costs, safety, residual environmental impact, even the sustainability and improvements of the current concrete manufacturing processes.
Delta Precast can help you reach all of your project goals. Lifting Calculations, Handling Analysis, Complex Structural Design, we are your precast engineering solution. Contact Daryl with your next project or call 607-231-6613.