4CCC raising funds to donate low

Block-Lite, a Flagstaff-based masonry company, has plans to go low carbon by 2024 by installing a new curing system that will take carbon dioxide from the atmosphere and inject it into its products as they cure, producing eco-friendly concrete.

Finished cinder blocks sit in the storage yard of Block-Lite's facility on Thursday, July 13. As part of a grant, 4CCC is raising funds to donate low-carbon concrete blocks produced by Block-Lite for starter homes.

An affordable housing project by Habitat For Humanity is under construction in this 2022 file photo.

The 4 Corners Carbon Coalition (4CCC) is fundraising to donate low-carbon concrete blocks for use in Habitat for Humanity of Northern Arizona’s next 50 Flagstaff starter homes.

In April, Flagstaff concrete producer Block-Lite and two partner companies received a $150,000 grant to retrofit its building for a new low-carbon process for making concrete blocks.

As part of that grant, 4CCC is helping raise funds for a community impact project.

Traditional concrete blocks tend to have high levels of carbon, due to both the cement needed to make them and the steam-proofing process involved. Block-Lite is working with partners to reduce and remove carbon from its concrete by using low-carbon waste materials and taking carbon from the air for the proofing.

Cement is the most carbon-intensive ingredient in concrete, according to 4CCC's director, Ramon Alatorre. To reduce the amount of cement needed in its blocks, Block-Lite is working with California company CarbonBuilt to instead use “calcium-rich waste materials” such as fly ash or coal tailings.

Cinder blocks cure inside Block-Lite's kiln rooms on the morning of Thursday, July 13. This room will see the most changes as Block-Lite attempts to go low carbon by installing a new curing system that will take carbon dioxide from the atmosphere and inject it into their products as they cure.

Adjustments to the process are what make the substitution work. After the blocks are mixed and formed, in both methods they are then placed in a chamber to cure. In the traditional process, this involves a steam chamber, which Alatorre said uses a lot of both water and energy. In the CarbonBuilt process, the steam is replaced with a carbon dioxide (CO2) chamber to cure the blocks -- which reacts to the waste materials and mineralizes them.

“Essentially, the calcium-rich materials bind with CO2 and it creates limestone within the block itself,” Alatorre explained. “You’ve taken this gaseous CO2, and it's gone through a mineralization process, and now it is part of the structure and bonded into the concrete blocks.”

The carbon-removing “magic” of the process, he said, is in where the CO2 for curing comes from. Instead of purchasing pressurized carbon dioxide, Block-Lite will be installing direct air-capture machines from another California company, Aircapture, that can pull carbon out of the atmosphere to use in the curing chamber.

"Some of that legacy carbon has been in the atmosphere for decades, if not centuries, and it's coming from the direct air-capture machine," Alatorre said.

Block-Lite is the first to combine these low-carbon methods into a single process.

Alatorre said he expected that between the two processes, the retrofitted production line would reduce and remove between 2,000 and 3,500 metric tons of carbon each year.

Using the low-carbon waste materials reduces 2,000 to 3,000 tons of carbon equivalent per line per year. Each direct air-capture machine removes an additional 100 tons of CO2 from the atmosphere each year, so the five or six units added for this project could remove between 500 and 600 metric tons of carbon from the atmosphere annually.

The roof of the curing building at Block-Lite will many changes as the company moves forward with its new low-carbon initiative.

Alatorre said he saw the project as an example of what carbon removal could look like at a small scale. He hoped the model developed at Block-Lite is replicated at other concrete block producers.

“The beautiful thing about the concrete industry is that it is such a distributed industry,” he said. “You don’t want to put concrete blocks on a truck and ship them 1,000 miles, so there are concrete block producers and ready-mix producers in almost every town in the U.S. ...It’s such a ripe industry for coming up with rapid replication of a lot of the things like this. Perhaps a lot of the concrete that we’re pouring or curing in the next decade would be helping to address the climate.”

Block-Lite is beginning the process of retrofitting one of its production lines, with the first of these new bricks expected to be produced in 2024.

As part of the grant, 4CCC is helping to fund an impact expansion initiative, which for Block-Lite is providing materials to use in Habitat’s Flagstaff starter home project.

The company had donated its traditional blocks to build the first two starter homes, and is now fundraising to be able to donate its new low-carbon blocks to the next 50 Habitat has planned.

Using traditional blocks would use about 3.5 metric tons of CO2 per starter home -- which Alatorre said “could essentially be eliminated or reduced by 70% to 100%” by replacing them with low-carbon blocks (the range comes from variables associated with the process, such as where the materials are brought in from and how much solar power is generated on a given day).

The blocks for each home cost about $1,000, so the fundraising goal is $50,000. In early July, the company had already raised over $20,000 -- enough to provide blocks for the homes built in the first two years.

“Part of the vision is we want to get these materials into the world and we want to show that there’s minimal, if any, green premium on this and these should just be standard,” Alatorre said.

Block-Lite, a Flagstaff-based masonry company, makes plans to go low carbon by next year by producing eco-friendly concrete.

The blocks do not cost more to produce, he said.

“These blocks can work for starter homes, they can work for anything in which blocks are being utilized,” he added. “ ... I would love if anything we're doing would be able to support [Habitat’s starter homes].”

More about the grant can be found at 4cornerscarbon.org/collaborations/carbon-removal-concrete/.

The city has not recorded significant rainfall since March 22. This stretch of no rain is the second longest in Phoenix's history. 160 days of no rain were recorded in Phoenix in 1972.

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