Concrete is a controversial topic in the sustainability landscape, but the narrow viewpoint may shift into one reveling in environmental potential. Innovators reimagined this ancient material into carbon-capturing precast concrete blocks.
Several companies are leading the charge to rebrand the concrete sector. Contractors and construction industry professionals are about to enter a new world of sustainable building as fewer emissions become possible.
What’s the Environmental Concern With Concrete?
Several toxic players in a concrete block cause environmental stress — though the main offender is cement. The calcium in cement makes it a top carbon emissions contributor at a jaw-dropping 8% of the world’s impact. Professionals seek to curb the emissions problem with precast concrete blocks, but there is more impact outside of greenhouse gas emissions.
Other materials go into concrete that is in questionable natural supplies. Aggregates like gravel may sound easy to include, but others like sand spark controversies regarding sand abuse when it is a deceptively finite resource. Organic processes grind up gravel and sand before use in concrete, so there aren’t any inherent carbon emissions with this step. However, it’s essential to acknowledge concrete creation has other environmental byproducts.
Cement’s heft is incomparable and installation on any soil that meets it will change forever. The ground moves and erodes, changing its makeup for more significant susceptibility to weather and erosion. What sits alongside cement in concrete isn’t healthy for soil either, altering pH in a way that damages wildlife. Though runoff could be prevented and recycled, this isn’t a practice many companies strictly enforce or widely adopt.
Precast concrete blocks help some environmental concerns over cast-in-place concrete installation, like wasted heat from firing for small projects or air pollutants from construction. But, precast concrete is also more transportation intensive and harder to modify, potentially encouraging waste.
How Can Concrete Absorb Carbon?
Some eco-conscious visionaries may want to find replacements for this harmful substance, though no viable options exist to perform the way concrete does. Others seek to reimagine its carbon story. Every project has the same goal — to capitalize on concrete’s natural carbon sequestration abilities and amplify it to its maximum capacity to outpace manufacturing emissions using precast and prestress business models.
The VTT Technical Research Centre Finland is investing in uncovering the potential behind carbon dioxide-made concrete blocks. Carbon dioxide can undergo mineralization to construct the block and take advantage of natural carbonation, which turns carbon dioxide in the atmosphere into calcium carbonate. Not only does the block’s composition inherently absorb carbon emissions — making it carbon-negative — but it also eliminates most of the need for concrete.
Purdue University researchers knew concrete could already sequester carbon dioxide, but the modern process of making concrete uses so many resources that humans can’t be patient enough to catch up — in fact, it probably can’t. So, what if they could figure out how to double its potential? Tests prove adding nanoscale titanium dioxide does the job if the ratio of cement paste, water and aggregates is ideal. If so, it will cause photocatalytic carbon dioxide reduction.
UCLA researchers take a slightly different approach by making concrete from fossil fuel emissions like coal plants. Instead of adding new items to a concrete mixture, they seek to revolutionize the cement by mixing it with the lime responsible for absorbing carbon dioxide during the final phases of creation. Using the resources already available could lead to less expensive alternatives.
How Else Can Concrete Deal With Carbon Emissions?
The impact of precast concrete blocks absorbing carbon emissions only reveals itself the more the concrete sector reduces its output. When concrete releases nearly 1,400 pounds of carbon dioxide for every metric ton of cement, it’s critical for concrete to rebrand with greener strategies. Otherwise, it could result in conflict with global climate goals. The chemical reaction of making it is the main culprit — not the fuel or power going into making it, though that is essential to weigh.
Like every other manufacturing outfit, concrete plants should employ process discovery to evaluate, streamline and optimize efficiency to reduce emissions. Though enhanced concrete could become a carbon sink, the job will be easier if the industry reduces how much the concrete will have to absorb. Here are some of the most compelling ways the sector could reduce emissions outside of making greener, carbon-absorbing concrete:
- Using other carbon capture utilization and storage technologies
- Installing renewable energy to reduce fossil fuel reliance on cleaner concrete firing
- Leveraging technology like the Internet of Things or AI to gain data about the impact
- Investing in external or internal R&D
So much of the concrete-making process — including novel carbon-sequestering precast concrete blocks — emits carbon dioxide and energy that can be caught and repurposed for other uses. One of the best ways to do this is by using data-driven insights to motivate changes. Concrete manufacturing that discovers all these opportunities will be forerunners in the industry and find the fastest to reduce carbon emissions and heal the carbon cycle.
Eventually, the hope is to find a more sustainable alternative to concrete. Unfortunately, it has yet to exist in a way humans could use it to the necessary scale — too much infrastructure worldwide relies on standard concrete’s stability. In the meantime, the efforts must focus on transformation instead of substitution. It will set an essential precedent for the climate conversation, because for progress to occur, there has to be a healthy combination of discovery and redesign for sustainable momentum.
Using Precast Concrete Blocks to Their Full Potential
Tackling the carbon footprint of the concrete industry will take numerous forms. Using precast methods over others is a solid starting point, but manufacturers can do more.
The shift will forge a path in concrete that instigates other eco-conscious changes in an ancient industry desperate for modernization. Investing in research to find new mixtures and compositions to exploit the potential of concrete’s natural carbon sequestration abilities could make it carbon neutral for itself and a carbon sink to help the rest of the planet’s emissions.
