Is 3D Concrete Printing Making its Mark on Commercial Construction?

What do schools in Africa, record-tall wind turbines, disaster-resilient army dwellings, hotels made of sand, and construction projects on the moon all have in common?

If you said “3D printing,” you’d be right, but it doesn’t tell the whole story. What sets these projects apart is that they stretch the limits of what’s possible with 3D concrete printing (3DCP) technology. 3D printing with concrete has been tested extensively across the globe, from commercial housing projects in Eindhoven, The Netherlands, to the first official commercial building in Dubai, United Arab Emirates. With concrete’s malleable yet hard-setting properties and 3D printers’ mechanical arms that can withstand extreme climates and difficult terrains, 3DCP offers many advantages to the commercial construction industry.

A 3D printed concrete wind turbine base made using the BOD 2 3D printer for GE. Image courtesy of COBOD.

Over 70% of the world’s population lives in concrete structures, and the demand for concrete and cement is only expected to increase—even wind turbines that harness renewable energy need concrete and steel to be built to last. Nevertheless, the cement industry is responsible for 8% of the world’s carbon dioxide (CO2) emissions that are slowly heating the planet. Today’s scientists agree that drastic action must be taken to keep the earth from surpassing 1.5 degrees of warming—a threshold that, if breached, holds catastrophic consequences. So, in a world heavily reliant on concrete, how can engineers cut emissions and make concrete greener?

Let’s take a closer look at the benefits of 3D concrete printing and how its additive manufacturing methodology may be a viable solution to mitigating climate change.

The Benefits of 3D Concrete Printing in Commercial Construction

Durability and safety are critical in any construction project, but for commercial buildings intended for extensive public use, the risks become all the more larger. Take bridges, for instance. In 2018, the Morandi bridge in Genoa collapsed during a bout of torrential rain—sending dozens of vehicles tumbling into the abyss. This bridge was part of one of the country’s most critical highways, connecting it to France, which brought international attention to the state of Italy’s infrastructure.

While 3DP bridges have been around conceptually since 2016, recent projects around the globe are bringing the additive manufacturing approach to life—with China and the Netherlands as pioneers in this space. Supported by 176 units of cement, the longest 3D-printed concrete bridge is found in China, which ferries passengers across the Shanghai Canal. At the same time, Amsterdam sports the world’s first 3D-printed steel bridge. Several sensors are attached to the bridge to help monitor movement, temperature, and vibrations in an effort to continuously maintain public safety.

The benefits of additive manufacturing are well-documented. With 3D printers engineers only use or ‘add’ the precise amount of material required to manufacture structures, maximizing resources and minimizing waste. Ghent University, which tested an additive-manufactured walkway, found that the 3DP construction required less material and had a reduced environmental impact.

Marines with 7th Engineer Support Battalion, 1st Marine Logistics Group, work together to secure a concrete bridge support column created using a 3D printer, during an exercise at Camp Pendleton, Calif. Marine Corps photo.

Not only can 3D printers build faster, but these tools also minimize strain on workers and reduce material wastage while maximizing precision. It’s not for nothing that the US Marine Corps are using 3D concrete printing to create custom-made bridges for crossing any void.

Is Sustainable Cement Possible?

It takes a lot of electricity to make large amounts of concrete, and further CO2 emissions are produced from the cement manufacturing process, a core ingredient of concrete. While renewable power grids could reduce emissions by 50%, transitioning is timely and costly. In fact, energy transition investment will have to increase to USD 4.4tn annually until 2050. In the meantime, rethinking construction processes and using more sustainable materials are crucial.

For instance, California has vowed to cut 40% of carbon emissions per ton of cement by 2035, while tech giants Microsoft, Google, and Salesforce, among 50 others, pledged to begin purchasing low-carbon versions of cement. There’s an army of researchers behind this pursuit. Already, researchers at Cambridge University claim the invention of the “world’s first zero-emissions cement”—Cambridge Electric Cement. So, how does it work?

When used cement is separated from recycled concrete, it ends up as slag, usually considered a waste product. It’s full of calcium oxide—a key ingredient in the clinker used to make cement , which creates 90% of total carbon emissions in the cement and concrete sector. The Cambridge team ground the recycled slag into a powder and found that it “is virtually identical to the clinker which is the basis of new Portland cement.”

Other ways to fortify concrete and reduce its carbon footprint are by adding recycled plastic to the mix. MIT scientists discovered that by pulverizing plastic flakes into a fine powder, they can mix them with cement paste and fly ash to produce concrete that is up to 15% stronger than conventional concrete.

Researchers at Technical University Berlin and Brunel University found that concrete can be made more robust and eco-friendly by partially replacing the sand in Portland cement with recycled glass, limestone, and plastic fillers. The team drastically improved its strength and thermal conductivity, building a lasting end product.

These innovations are already being adopted by some of the leading building materials companies. In 2020, CEMEX introduced its version of net-zero CO2 concrete called Vertua, which has a measurable environmental impact.100 bags of traditional cement replaced with Vertua cement is equivalent to taking 105 cars off the road for one day, representing a 1.3-ton decrease in CO2 emissions.

The Opportunities of 3D Printing With Sustainable Concrete

We have established the benefits of 3D printing construction technology and the innovations related to sustainable concrete. Both these forces combined bring a new era of sustainable and ecologically-conscious building to non-residential structures.

Looking back to 2015, material science engineer and hotel owner Lewis Yakich used 3D printing technology in the Lewis Grand Hotel. Yakich worked with 3D printing specialist Anthony Rudenko to create the first 3D printed hotel suite in just 100 hours. This example perfectly illustrates the noteworthy time efficiencies and cost savings (up to 60% in this case) that 3D printing provides when compared to traditional construction methods. Now imagine replacing the concrete in these projects with sustainable substitutes and the advantages increase exponentially!

Already in 2019, these two innovations were put into practice in Mozambique where engineers constructed the world’s first luxury 3D-printed sand hotel, built with a sand-and-seawater mortar. Using locally available materials means designers and engineers can also save on transport costs and emissions in the process.

We live in an age where technological breakthroughs are commonplace. And yet, these breakthroughs take time to become widely adopted. As we build for the future, we can expect to see more engineers continue experimenting with 3D concrete printing and sustainable raw materials in commercial projects, monitoring their durability over time to ensure public safety and reduce their carbon footprints.

About the Author

Ibon Iribar, Investment & Open Innovation Advisor at CEMEX Ventures, deeply explores and analyses advanced technologies for the construction industry and helps identify investment and business development opportunities with new startups, projects, and entities of the construction technology ecosystem across multiple markets. Ibon leads the efforts for the biggest challenge for construction startups, Construction Startup Competition, and works year-round seeking the most innovative and promising solutions to invest in or collaborate with, supporting startups´ development and their growth within the built environment.