Concrete 3D Printing Tech

3D printing got its start in materials like plastic and metal, but the technology is expanding in both materials used and in scale, and concrete is the next path to be traveled.

Innovations in concrete are growing more prevalent in the built environment due to its many positive qualities as a building material. It has long been the most widely used construction material on earth, due to its malleability when newly mixed, strength and durability when hardened, cheaper utility bills and less wear on the environment, and cheaper insurance costs on the structures it forms.

It makes sense that the draw of concrete would link up with the draw of 3d printing – reduced supply chain length, reduced supply costs, greener construction, improved project planning through the ability to quickly and inexpensively create models and streamlined client expectations – with the potential for industry-changing results. [source: thebalancesmb.com]

In an August 2018 article for All3DP titled, “Concrete 3D Printing – How it Works and the Applications,” author Leo Gregurić provides an in-depth lesson on how 3D printing works, as well as how it’s being used in architectural pursuits today. All3DP bills itself as the “World’s Leading 3D Printing Magazine with Compelling Content. For Beginners and Pros. Useful, Educational, and Entertaining.” If you’re interested in learning about any number of 3D printing-related topics, All3DPis a great resource.

Mr. Gregurić writes, “All in all, the main idea behind concrete 3D printing is that an architect or designer can convert their 3D blueprints into g-code and send it to the printer. This concrete 3D printer can then immediately turn their idea into reality, significantly reducing the build time and costs in comparison to traditional building techniques.”

“To get an idea of how concrete 3D printing works, imagine a gigantic FDM 3D printer that uses concrete instead of plastic filament.

Concrete 3D printers, just like FDM printers, are controlled via g-code, a machine language that works by directing the print head of the 3D printer until the desired 3D model is produced.

Concrete 3D printers and ‘normal’ FDM 3D printers are both similar in some ways and very different in others. In fact, the similarity between plastic FDM printers and concrete printers can be summed up in basically two words: material extrusion. Just like ‘normal’ FDM 3D printers, concrete 3D printers also operate using X, Y and Z axis.

The x-axis of a concrete 3D printer is defined by the length of the rails which are used for moving the printer head back and forth. The Y-axis of the concrete 3D printer is defined by the distance between rails on opposite sides and the Z-axis is defined by the height of the pillars which carry the nozzle.”

Mr. Gregurić notes that concrete 3D printers haven’t eliminated their human construction job equivalents…yet; rather, the tech has made construction workers’ jobs easier and safer. Down the road, that aspect of the job could change.

“Obviously, the foundation is needed before houses/buildings can be built above the surface. One of the first steps in preparing the construction site for a concrete 3D printer to arrive is to flatten it so that rails for the printer can be installed. Apart from creating a surface flat, foundations are needed before the process of printing concrete can start.

As we mentioned above, one of the first steps workers need to do in order to start printing concrete is to deposit specially designed rails for the printer. The next step is to put the printer on the rails, set up the pillars and check all three axes. The nozzle and a robotic arm are located on a horizontal metal beam that’s put across the pillars of the concrete 3D printer.

When the 3D design of the house is ready, concrete comes to the construction field – usually in a normal concrete truck – and is connected to the printer’s nozzle via a big hose.

At this point, you might be asking yourself how electrical installations and reinforcement of the walls are implemented during the concrete 3D printing process. It can all be done during printing thanks to recent developments of the companies that specialize in concrete 3D printing, such as CC Corporation.

Special methods of wall reinforcements are developed by firms that specialize in 3D printing to make bare concrete walls even stronger. Window frames and ceilings are pre-manufactured and installed by a robotic hand that “sits” alongside the nozzle. The concrete that gets printed has to be carefully prepared in order to successfully print buildings.

The goal would be to achieve a concrete mix which is able to provide maximum buildability upon pouring of the concrete and to maximize the flowability of the concrete mix to ensure the nozzle doesn’t get clogged. To say it simply, the goal is to have layers that harden quickly but remain liquid enough to successfully bond with new layers.

To achieve such great performance, the concrete mix must contain perfect amounts of chemicals, such as superplasticizers. Superplasticizers are used to reduce water in a concrete mix. If you want to know more about superplasticizers, learn more here.

Apart from various additives that are put into the concrete mix, manufacturers also improve the strength of the concrete by adding fibers into the mix itself.”

Mr. Gregurić also provides a few helpful notes on the nuances in vocabulary surrounding construction 3D printing:

“When talking construction 3D printing, people often use abbreviations such as 3DCP (3D construction printing) and LSAM (large scale additive manufacturing). One of the most promising methods of concrete 3D printing is called Contour Crafting (CC).”

“All concrete 3D printing technologies are based on the same concept – which is similar to ‘normal’ FDM printers, but various concrete 3D printing technologies differ in terms of how reinforcements are installed and many other details such as wall thickness and the geometry of the concrete inside the wall’s ‘shell’.”

3D printing in the A&D community, and in contract furniture manufacturing, has for the most part been confined to modeling and prototyping.

In life-size, end-project construction, thus far concrete 3D printing has seen the most movement in affordable housing – a market segment familiar to the origin stories of many new technologies. Affordable housing is an excellent ground on which to experiment with low-cost, high-functioning tech whose legitimacy and benefits are still being proved.

Mr. Gregurić tracked down some of the most recent and relevant applications of concrete 3D printing on a larger scale:

“Earlier this year, the Texas-based company ICON announced that it had managed to 3D print a 350-square-foot house at an affordable price of $10,000. ICON is working closely with a non-profit organization New Story with a goal of printing homes in El Salvador at $4,000 per home, each being around 600-800 square feet. As they claim, they are working “full throttle” to reduce the price of 3D printed homes, aiming to make housing more affordable all around the world.

Perhaps you’ve also heard about a man named Andrey Rudenko who 3D printed a castle in his own backyard. Andrey said he always believed that something like that could be done and he was right, he proved his statements with the castle he printed in his backyard.

One country that is especially fond of using 3D printing to build homes and bridges is the Netherlands. In 2019, the Dutch city  Eindhoven will receive five new houses that will be constructed using special concrete 3D printers. The homes will be inhabited by families, and the biggest of the five houses will include three bedrooms and three floors.

The Netherlands is also home to the world’s first concrete 3D printed bridge for cyclists and pedestrians. This structure was made by the same firm that is providing the equipment that will be used to build the 3D printed houses in Eindhoven. The bridge is made up of several 3D printed concrete sections.

Another great example of how concrete 3D printing is used is provided by the firm called XtreeE, one of the pioneers in the concrete 3D printing sector.

They are 3D printing benches with woven patterns for backyards and parks, but also they do larger-scale projects like house construction. The company also 3D prints concrete facade panels as decor for modern buildings.”

At officeinsight we’re following innovations in concrete closely and plan to provide regular updates on its current state of use and the latest and greatest in new forms and technologies being applied in the industries we cover.