With embodied carbon being a key discussion point in construction recently, demand for low carbon building materials is increasing. Concrete gets a bad rep in these discussions due to the high emissions associated with it.

 being a key discussion point in construction recently, 

 for low carbon building materials is increasing. Concrete gets a bad rep in these discussions due to the high emissions associated with it. However, it’s difficult to imagine a world where concrete is not used at all, and therefore the industry has made significant investments to develop lower-carbon concretes.

But what is low carbon concrete and how can it be adopted at scale to help the industry remain within planetary boundaries?

In this post we address the following questions:

Why does traditional concrete have such a high footprint?

In its simplest form, concrete is a mixture of paste and aggregates, or rocks. The paste, composed of cement and water, coats the surface of the fine (small) and coarse (larger) aggregates. Through a chemical reaction called hydration, the paste hardens and gains strength to form the rock-like mass known as concrete.

One reason why the carbon emissions are so high is because cement has to be heated to very high temperatures in order for clinker to form. A major culprit of this is alite (Ca3SiO5), a mineral in concrete that cures within hours of pouring and is therefore responsible for much of its initial strength.

Low carbon concrete is concrete produced with a lower carbon footprint than traditional content. Other than a reduced carbon footprint, low carbon concrete should behave identically to its high carbon counterpart.

To create low carbon concrete, producers can implement a series of relatively low-impact changes to their production processes and mix designs.

There are 3 ways by which concrete manufacturers can reduce the carbon emissions related to their products:

Switch the fuel source to a fuel generating less emissions.

This means moving from traditional fuels (e.g. coal) to lower-carbon fuels (e.g. renewable natural gas), waste fuels (e.g. non-recyclable plastics, non-recyclable tires, rail ties, etc.), and potentially even carbon-neutral fuels.

Replace some cement content with mineral compounds.

A few substitutes to cement which can reduce the emissions in concrete are:

- Fly Ash (by-product of coal-burning power stations)

- Ground Granulated Blast-furnace Slag (GGBS) (by-product of the Iron and Steel Industry)

- Silica fume (by-product from the manufacture of silicon)

Install Carbon Capture and Storage technologies on-site

Innovation in carbon capture, utilization, and storage (CCUS) technologies is an exciting development in the concrete industry. Carbon capture

makes it possible to capture up to 100% of the carbon emissions from cement manufacturing. These captured emissions can be stored safely underground, injected back into concrete to strengthen it, or used to make other products like synthetic aggregates or fuels.

Depending on the fuel used and the dosage of the additions, the carbon footprint of concrete can be reduced by up to nearly 70%.

While there’s been amazing progress in lowering carbon’s footprint, the industry still has big challenges.

Here’s some things to note around the technologies which limit their scalability today:

Alternative fuels today can reduce emissions by a small amount and face 

 in being adopted globally such as high costs, limited range, etc.

Cement replacements such as fly-ash and slag are finite. There isn’t enough slag and fly-ash in the world to apply it to all the concrete being produced.

Cement replacements are reducing. Since these are by-products of other sectors (some of which are winding down globally) their availability is becoming constrained.

Carbon Capture and Storage is an expensive technology that needs further development to be applied at scale.

Future Thought Leaders is a democratic space presenting the thoughts and opinions of rising Energy & Sustainability writers, their opinions do not necessarily represent those of illuminem. 

A simple guide to Low-Carbon Concrete

Climate change and climate solutions are all over the news. You’ve probably heard the story a million times already: The world is emitting so much that our future is starting to look grim.

Climate change and climate solutions are all over the news. 

You’ve probably heard the story a million times already

The world is emitting so much that our future is starting to look grim.

 we are not doomsayers. We of course understand that the world needs solutions, but our approach is simple: 

stay positive, and build tech to transition to the low-carbon economy

Why is it so important to stay below 1.5 degrees?

1.5 degrees is the global climate change goal world leaders agreed to strive for. By limiting the planet’s warming to 1.5 degrees Celsius, or 2.7 degrees Fahrenheit, by 2100, the hope is to avoid severe climate disruptions that could exacerbate hunger, conflict and drought worldwide. So, pretty important stuff to avoid.

The construction sector overall is responsible for 40% of the world’s emissions. That means investors, owners, architects, contractors, and other stakeholders have a huge opportunity to contribute to a world that looks better for all of us.

Specifically, at 2050 Materials we are here to help the construction sector design using more sustainable building materials. To do that, we simplify data around construction products (check it out 

 that allow practitioners to communicate the impact of each decision they make.

Below, you can learn more about how we calculate the “Warming Potential” metric, a metric that aims to show what climate scenario your chosen design is contributing to.

How can one building cause so much warming?

You are right, it can’t. In the same way that a single person skipping a transatlantic flight cannot reverse climate change, a sustainable building is not the solution to all our problems.

It is however, one piece of the puzzle. At 2050 Materials, we think that every change to a more sustainable system is important.

 was developed exactly to show what would happen if every building was designed in a specific way. It is a metric that tries to communicate impact and contribution on a high level, and a conversation started on 

To calculate the Warming Potential of a building, one needs to benchmark the emissions on a normalized unit and then compare those to building emissions that correspond to each climate scenario. To do that, we perform the following steps:

Compute the embodied carbon footprint of the building based on the A1-A3 GWP of the materials selected, taking into account their quantities.

Divide the emissions by the Gross Internal Area (GIA) to get the footprint per meter squared.

Compare those emissions per m2 to a benchmark set by 

 for net-zero (which we consider to be aligned with 1.5 degrees of warming). This is dependent on the type of building.

Extrapolate the 2 degree and 3 degree warming benchmarks by using the required global emissions reductions from 1.5 degrees to each scenario accordingly. To do this, we utilize data from the 

 for the material configuration selected.

As in all models, we make certain assumptions which allow us to compute the warming potential. The most important assumptions to keep in mind when using the data in these tools are:

In order to calculate Warming Potential contribution, we assume that business-as-usual proceeds in the economy, and all buildings are build with the same carbon intensity as the configuration selected.

We only take into account life-cycle stages A1–A3 (Manufacturing of raw materials) for now. Other life-cycle stages (transport, end of life, etc.) can have a significant impact on the embodied carbon of a building.

 is in line with a 1.5 degrees scenario of warming.

We use the relative reduction requirements indicated for global emissions, and apply them to adjust the LETI targets to 2 and 3 degrees of warming.

At 2050 Materials, we take feedback from our users very seriously. We know this model isn’t perfect, but we think that it can be, with 

Future Thought Leaders is a democratic space presenting the thoughts and opinions of rising Energy & Sustainability writers, their opinions do not necessarily represent those of illuminem. This article is also published on

Aligning material selection with global climate targets

 where they focus on raising awareness and helping companies build more sustainably by using more environmentally friendly materials and practices. He is also an 

environmental engineer graduate and versed graphic designer.

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Phanos Hadjikyriakou

Phanos Hadjikyriakou

Aligning material selection with global climate targets

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