Carbon Mineralization: An Easy-To-Adopt Solution for Sustainable Cement & Concrete

As the cement and concrete industry grapples with government regulations and growing demand for greener materials, carbon mineralization is the next logical step toward a decarbonized sector.

The concrete and cement industry has been applying carbon reduction best practices and technologies for some time. However, today’s most widely used methods—such as improvements in energy efficiency, increased use of alternative fuels, reduced clinker/cement ratio—are not nearly enough to meet the industry’s climate goals according to the 2050 Roadmap for Net Zero Concrete by the Global Cement and Concrete Association (GCCA).

Deployment of today's disruptive climate solutions can be risky, not ready to scale and cost prohibitive without government incentives. For solutions to succeed in our industry, they need to provide value to the producer. Solutions that can be retrofitted to facilities may help avoid stranding assets while offering low capital pathways to accelerate the rate of transformation. New and stable sources of climate financing are also needed to expedite the decarbonization of cement and concrete for the industry to meet its 2050 and interim targets.

Carbon mineralization technologies, such as CarbonCure, are a relatively new but proven solution. They offer an immediate impact, with a simple, low cost retrofit, plus application across geographies and project types. Not only does carbon mineralization reduce concrete’s carbon footprint, it results in cost savings through cement optimization, avoids a green premium and creates a differentiated sales advantage. These technologies are also supported by novel climate financing options such as voluntary carbon markets, chain of custody frameworks and direct procurement by public and private entities. 

How Carbon Mineralization Works

Carbon mineralization is a method of carbon capture, utilization and storage (CCUS) whereby captured CO2 is injected into fresh concrete while it's being mixed. Immediately upon injection, a chemical reaction takes place between the calcium oxide in the product’s cement and the CO2 that is introduced by the CarbonCure system. This reaction creates nano-calcium carbonate (CaCO3) minerals that become permanently embedded. 

CarbonCure has worked with industry leaders and research institutions to conduct studies of its technologies, including the amount of CO2 uptake in concrete via carbon mineralization. Its most recent testing demonstrated a strong linear relationship between injected and mineralized CO2 with an average uptake of 90%.

Mineralization protects the concrete’s compressive strength without altering pH. This enables producers to safely adjust cement content across concrete mix designs. For every metric ton of mineralized CO2 in ready mix concrete, CarbonCure producers can avoid another 50 metric tons of CO2 by optimizing cement.

This is a solution that can be applied across the concrete manufacturing process. In addition to technologies that reduce emissions in ready mix and precast concrete, CarbonCure is developing and piloting similar carbon mineralization systems for reclaimed water systems and recycled concrete aggregate. 

Ultimately, these technologies can be used together for greater carbon savings: When CarbonCure for Ready Mix and CarbonCure for Reclaimed Water are used together, producers can save 12 to 22 kilograms of CO2 per cubic meter (25 to 50 pounds of CO2 per cubic yard) compared to conventional concrete. When stacked, they can achieve roughly 10% carbon savings without any capital expenditure investment or disruption to their supply chain. 

A Simple Retrofit With Significant Results

CarbonCure retrofits existing concrete plants with its technologies with minimal disruption. Field engineers simply bolt a system onto any dry or wet batch ready mix or precast plant configuration and CarbonCure’s software integrates seamlessly with existing batching software, administering the carbon dioxide (CO2) just like an admixture. The CO2 tank is installed in  advance by a third party, and refilled by gas companies on a regular basis. CarbonCure engineers hook the equipment up to the CO2 tank and plant batching system in mere hours. In the future, this CO2 may be sourced from cement kilns or direct air capture projects; however, presently post-industrial CO2 supplies are abundantly available from established supply chains. 

A CarbonCure Ready Mix system operates at a Thomas Concrete plant.

Founded in 2012, CarbonCure developed and commercialized its technologies over the past decade, now with hundreds of concrete plants across dozens of countries supplying thousands of commercial, infrastructure and residential construction projects around the world. Its carbon mineralization solution won the grand prize of the $20 million global NRG COSIA Carbon XPRIZE competition in 2021 that focused on scalable carbon utilization technologies. To date, CarbonCure has been used to produce more than 6 million truckloads and 38 million cubic meters of lower carbon concrete. So far, this has resulted in more than 400,000 metric tons of carbon savings. That’s equivalent to taking more than 88,000 gas-powered cars off the road for a year, or the carbon sequestered by more than 193,000 hectares (477,000 acres) of forest.

Pioneering Projects Using Concrete with Carbon Mineralization

An average mid-rise building using ready mix made with CarbonCure would save approximately 680 metric tons of CO2, which is equivalent to the carbon absorbed by 888 acres (359 hectares) of forest in a year.

There are already thousands of projects worldwide using this concrete, including roadways, runways, homes and high rises.

300 North Michigan Avenue

Ozinga Ready Mix supplied the concrete for this 25,000-square-foot high-rise situated just blocks from several of Chicago’s most visited tourist attractions, including the Magnificent Mile and Millennium Park. Developed by Sterling Bay and Magellan Development Group and designed by bKL Architecture, 300 North Michigan Avenue is not just a beautiful building, it’s also sustainably built using a CarbonCure mix.

Amazon HQ2

Amazon's HQ2 in Arlington is a large-scale project incorporating public spaces, commercial zones and community areas into a vibrant hub. Its construction — a collaboration among Thornton Tomassetti, ZGF and Clark Construction — was an exercise in sustainable innovation. The 106,555 cubic yards (81,467 cubic meters) of concrete for the project — supplied by Vulcan Materials and Miller & Long — used CarbonCure's ready mix technology. This contributed to a 20% reduction in the carbon footprint of the project’s concrete structures compared to the industry baseline, aligning with Amazon's sustainability goals.

GM Assembly Plant

Irving Materials, Inc. supplied more than 27,000 cubic yards of lower carbon concrete made with CarbonCure’s technologies for the GM Spring Hill Assembly Plant project in Spring Hill, Tennessee. Constructed by Walbridge Building, this manufacturing plant will assemble the all-new Cadillac LYRIQ, a luxury electric vehicle.

Financial Incentives that Encourage Adoption 

In addition to creating value for the producer through cement efficiency, CarbonCure’s approach leverages the voluntary carbon market to deliver additional, zero-interest financing to concrete industry partners. Corporations with ambitious climate commitments increasingly rely on carbon credits to reduce climate impacts when they can’t directly cut their greenhouse gas emissions. A wide range of credit types and prices have entered the market to meet demand but CarbonCure’s credits are among the highest integrity products on the market. 

This is due to the telemetry and precise accuracy of carbon savings afforded by CarbonCure’s systems, the high certainty that mineralized CO2 can never be released into the atmosphere and the only Verra-approved methodology for an engineered carbon removal technology. As a result, CarbonCure has been able to monetize these carbon savings at a price premium, sharing the proceeds with its concrete producer partners to support their operations and reward their sustainability.

Through credit generation, hundreds of concrete producers help corporate buyers reduce their climate impact even though they’re not taking physical delivery of the lower carbon concrete. This novel approach allows climate conscious buyers to connect with and finance the climate-improving technology costs of upstream sellers who aren’t directly part of their supply chain. Similar systems have helped scale renewable energy, sustainable aviation fuel and other low carbon solutions in high emitting sectors. As the approach gains acceptance in the buildings sector, it can help producers add new value streams, all the while driving down the carbon impacts of cement and concrete.

Crews pour CarbonCure concrete at Amazon HQ2 in Arlington, Virginia.

Low-Hanging Fruit for GCCA’s Net Zero Roadmap

The industry doesn’t just need climate solutions. It needs solutions deployed quickly and affordably. The Global Cement and Concrete Association aims for complete decarbonization by 2050. In the interim, GCCA is also targeting a 20% reduction of CO2 per metric ton of cement and a 25% reduction of CO2 per cubic meter of concrete by 2030. Such an ambitious timeline requires ready-to-deploy solutions that manufacturers can quickly adopt and easily implement. 

The GCCA strategy also emphasizes the use of carbon capture, utilization and storage (CCUS), with CCUS expected to contribute more than a third of the industry’s emissions reductions by midcentury; other substantial CO2 savings are attributed to cement optimization. CarbonCure’s technologies enable both and harness novel carbon finance solutions to accelerate deployment.

With 2030 on the horizon, this carbon mineralization approach can serve as a bridge, compatible with a portfolio of emerging solutions that will further drive down the industry’s emissions by midcentury. In the near and long term, this green transition will reward concrete innovation and the early movers who embrace it, with carbon mineralization exemplifying how environmental responsibility can coexist with operational efficiency and deliver economic benefits. 

Learn more about carbon mineralization and how CarbonCure is leveraging it to advance industry sustainability and profitability.

This article was published in the May 2024 issue of International Cement Review.

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