The new tech enables concrete producers to cut down on virgin cement, recycle water, reduce operational costs and earn verifiable carbon credits
When a concrete finisher heard that Trio Ready-Mix was planning on using reclaimed water in its mixes, he raised his eyebrows and his concerns to Trio’s general manager, Stephen Hay. Trio had recently built a new concrete plant in downtown Victoria, British Columbia, Canada and announced it had installed the XPRIZE-winning CarbonCure Reclaimed Water technology. “He was amazed when I informed him that we had been using it in our mixes for over a year —he hadn’t noticed a difference!” said Stephen.
CarbonCure Reclaimed Water enables concrete producers to re-use their reclaimed water in new concrete mixes in a reliable, predictable manner without adversely impacting the end product. That in and of itself is “life altering” for concrete producers, but the benefits don’t stop there. There’s a truckload of sustainability wins (including mineralizing large quantities of CO2 and reducing embodied carbon), cost savings, new market opportunities and even a completely new revenue stream.
How does CarbonCure Reclaimed Water work?
It’s based on the same core technology used in CarbonCure Ready Mix, a carbon mineralization process that produces low carbon concrete already being used in hundreds of plants around the world. The technology injects captured CO2 into concrete as it is being mixed, where it reacts with the cement and is chemically converted to a mineral that enhances the strength of the concrete mix. The added strength enables a reduction of cement content, without impacting its performance or properties. As we like to say: same concrete, less carbon.
Similarly, with CarbonCure Reclaimed Water, the CO2 is injected into the slurry from a unit installed on top of the reclaimer system’s agitated tank. The CO2 reacts with the cement in the slurry, producing that same mineral as an ultrafine suspended solid. The mineral acts as a binder, reducing the amount of cement needed. The reaction of CO2 is monitored in real-time using specific measurements to better understand the composition of the reclaimed water. This enables its use as a stable, reliable value-added product, rather than an inconsistent nuisance affecting concrete performance.
When CarbonCure Reclaimed Water is used in conjunction with CarbonCure Ready Mix, the virgin cement content of the concrete — and its overall embodied carbon — can be reduced even further.
8 Benefits of CarbonCure Reclaimed Water
1. No adverse impact on the properties of fresh or hardened concrete.
Traditional reclaimed water can reduce pumpability, make finishing difficult, reduce set times, reduce strength – or deliver any unpredictable combination of these. With each new batch, depending on the concentration of cement in the reclaimed water, you couldn’t be sure of what you’d get. But with CarbonCure Reclaimed Water, there’s a neutral impact on fresh properties and hardened properties (freeze-thaw, pH, density, durability and texture) and compressive strength is highly comparable and predictable.
2. Saving fresh water.
While typically you had to limit the amount of traditional reclaimed water used, you can reuse as much of the CarbonCure Reclaimed Water as you want — which can save up to 20% of freshwater use in your new mixes! Saving water is important for individual producers and for the global concrete industry, which each year uses 1 billion cubic meters (1.3 billion cubic yards) of mixing water.
3. Reducing virgin cement content.
CarbonCure Reclaimed Water can reduce virgin cement use in mixes by about 3-5%. When combined with CarbonCure Ready Mix the total reduction climbs to 8-10%.
4. Reducing embodied carbon.
The process of making cement, the key ingredient that gives concrete its strength, is responsible for about 7% of global CO2 emissions, making it one of the larger contributors to the industry’s carbon footprint. Using CarbonCure to produce concrete reduces embodied carbon in two ways: converting CO2 into a mineral and reducing the cement required. At Trio, for every cubic meter (1.3 cubic yards) of concrete produced with CarbonCure Reclaimed Water, about 1.1 kilograms (2.4 pounds) of CO2 is permanently mineralized; and an additional 8 kilograms (17.6 pounds) of CO2 is reduced.
5. New revenue stream with verifiable carbon credits.
When you employ CarbonCure Reclaimed Water, you generate carbon removal credits through our verified Carbon Dioxide Removal Credit Program. Carbon credits that are measurable and can be trusted are in high demand and valuable. Because our methodology for calculating the carbon credits has been scientifically verified by Verra, they are high-quality. These credits create a completely new revenue stream. The more CO2 you save by using CarbonCure, the more credits you can potentially generate.
6. Eliminate the need for residue disposal.
Whether you currently use any of your reclaimed water or not, chances are that eventually you have to do something with excess slurry or solids residues passing through your reclaimer system. That takes resources someone on your team has to monitor and manage the solids in your storage tanks. You have to haul it away for safe residue disposal. With CarbonCure Reclaimed Water, you’re minimizing all of that because you’re treating the slurry on site and reusing it in your new batches.
7. Cost savings.
You’re probably already tallying up the benefits to your bottom line: reduced material costs for concrete, reduced operational costs for transportation and proper disposal, and new revenue through carbon credits. While every producer’s numbers will be different based on local variables, Trio estimates its average savings (after carbon credit revenue) to be CAD $0.90 per cubic meter of concrete when producing with CarbonCure Reclaimed Water.
“Our initial motivator was environmental, not monetary," said Stephen. "However, we have seen a great return on investment. The virgin cement replacement is where true environmental and cost savings are, but the water treatment and the savings on the cost of safe fines disposal are also significant.”
8. New opportunities for market differentiation and growth.
The green building materials market is expected to grow over 9% in the next five years. The demand for sustainable, lower carbon concrete is only going to continue as the global community – including the construction and concrete industries – commit to net zero buildings and carbon neutrality by 2050. Concrete producers who are using CarbonCure are able to capitalize on their sustainability brand and stand out from their competition.
Interested in learning more about CarbonCure Reclaimed Water? Watch our webinar How to Unlock Value from Returned Concrete and Reclaimed Water or read the Trio Ready-Mix case study.