We have bad news, and we have good news. Since we are the kind to just rip the band-aid off, here’s the bad news: our infrastructure is in bad shape. We’re getting poor marks from the American Society of Civil Engineers… according to them, tens of thousands of our bridges across the country have been rated as “structurally deficient” and roadways, ports, and waterways are in disrepair. Estimates put the cost of repair in the trillions.

Now, for the good news: since our infrastructure needs replacing anyway, now’s the perfect time to build differently… to build with our health, and the health of the earth, in mind. See, currently, concrete has a huge impact on the planet, accounting for about 8% of emissions. And since concrete ranks right up there with water in terms of demand, we’re talking a large overall impact. Just think about all the concrete in the world.

A major problem with concrete isn’t just that it traps heat, but that the manufacturing process for it involves extreme heating of the elements of the concrete, which releases carbon dioxide. Also, it’s energy intensive. But… what if we could take these weaknesses, and exploit them to turn the tables? What we’re talking about is using concrete to store carbon, or even figuring out a way to make concrete a carbon sink.

In California, tests for just this thing have been happening. Two companies, Heirloom Carbon Technologies and CarbonCure, have been working on pulling carbon from the air to store in concrete. They successfully tried it recently, when they injected freshly poured concrete with CO2 to form calcium carbonate. This is good, because calcium carbonate is a stable form of carbon that won’t release back into the atmosphere.

Getting this right would impact more than meets the eye, because it’s not as easy as you would think right now to get your hands on CO2. That means we’ll need more reliable companies pulling it out of the air and supplying it to folks like this for things like this. Oh, we forgot to mention, the concrete made with the captured CO2 turned out to be stronger than traditional concrete. So far, we’re seeing nice upsides.

The aforementioned Heirloom Carbon Technologies is a California startup hoping their work with CarbonCure (specialists in carbon-neutral concrete) can be impactful enough to be considered a model for fighting climate change. The company, which soaks carbon from the air using rocks, supplied the CO2 Vulcan Materials’ subsidiary Central Concrete used for incorporation into test concrete.

California isn’t the only state with folks eyeing carbon capture concrete. In Alabama, LA-based CarbonBuilt is producing some of this neato low-carbon concrete. Along with their production partner Blair Block, CarbonBuilt aims to help reshape the space and “massively reduce carbon emissions” while doing it… all while not bending on cost and performance. Their particular production process utilizes calcium-rich industrial waste materials.

The company got it’s start not that long ago in 2014 as a creation of UCLA’s engineering school, became independent in 2019, and made swift work of winning the 2021 $7.5 million NRG Cosia Carbon Xprize. It’s impressive because this competition, launched in 2015, is only looking at innovators that successfully develop breakthrough technologies that convert CO2 emissions into usable products.

Next, we just need to make it so concrete eats carbon… that would be perfect. MIT engineers want to make that happen with additives introduced to the manufacturing process that promote carbonation. This process, which occurs naturally in concrete as it absorbs CO2, gets sped up by these additives. The idea is these can be added now to current processes, and they don’t impact things like strength or durability.

And they aren’t the only ones, engineers at Washington State University have developed their own method of concrete production that absorbs more carbon than it emits. These guys decided to use something called biochar as an additive, which is a type of charcoal made from organic waste. Their angle was also to enhance strength and carbonation.

According to them, the concrete produced using their method could remove up to 23% of its weight in carbon over its lifetime. Also, don’t worry… when they say “biowaste”, they mean agricultural waste, like corn stover and rice straw. Now, we just figure out how to do this at scale (which we’re working on), and we have real possibilities ahead of us for a concrete makeover. Come back next week for more from the green tech space.