Everyone knows the famous 18th-century story of the three little pigs, popularized by Walt Disney in 1933. In it, one lazy pig built a house of straw, the second, a bit more industrious, opted for wood, while the third, hardworking pig, decided to build a house of bricks, which turned out to be the most resistant to the attempts of the wicked wolf to blow it down. Today, the first two would never have thought that their materials would be used in construction and that natural or sustainable building would become something to strive for. Natural materials are becoming increasingly popular, and with new advanced technological methods, everything is becoming simpler, cheaper, and more environmentally friendly.
The construction industry, like all others, is undergoing a period of rapid change and innovation. The greatest role in this story is played by new technology and sustainable materials, which are becoming key to shaping what is now commonly referred to as urban areas, opening up new possibilities in ecological construction, architecture, and design. Due to ecological challenges, there is an increasing emphasis on construction methods that reduce emissions and material consumption, as less material also means a smaller ecological or carbon footprint. In this context, 3D printing has emerged as one of the most promising technologies.
Chinese Pioneers
The technology of 3D printing in construction began to develop in the early 2000s, but widespread application and the first concrete projects only appeared after 2010. It is not surprising that the Chinese company WinSun is a pioneer in this field, given the increasingly advanced Chinese technology in almost all industries. In 2014, WinSun was the first to build several houses using the 3D printing method. It printed wall sections from concrete in a factory and then assembled them on-site, demonstrating how this method can accelerate construction and, more importantly, reduce costs.
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Less raw materials also means a smaller carbon footprint. Under this slogan, urban planners emphasize construction methods that reduce emissions and material consumption.
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We had to wait until 2017 for large objects printed with a 3D printer when the Russian company ApisCor printed an entire house directly on the construction site in Stupino, near Moscow. Using a large robotic arm, it completed the structure of a concrete house in just 24 hours, showcasing the efficiency of this technology in constructing larger residential buildings. After that, the technology expanded to other construction projects, including bridges. An example is the Royal BAM Group, which in 2017 built the first 3D printed concrete bridge in the Dutch village of Gemert in collaboration with researchers from the Eindhoven University of Technology. This project was significant as it demonstrated the potential of 3D printing in infrastructure construction, especially under demanding conditions such as bridges that must withstand heavy loads.
Types of Printing
As previously mentioned, 3D printing allows for the creation of construction elements or entire buildings layer by layer. So far, materials such as concrete, various polymers, metals, recycled materials, and recently clay have been most commonly used. The most common type of printer is based on a robotic arm that moves back and forth, extruding material. In addition to this method, there are others, such as powder binding and additive welding. Powder is bound within a pool filled with powder, where it solidifies layer by layer to create the desired object. Additive welding is a metal 3D printing technology that uses heat and metal wires to build metal structures layer by layer. This technology has been increasingly used, especially in industries such as automotive, aerospace, and shipbuilding, where the production of large and precise metal parts is required.
Without Cement
The ongoing development of three-dimensional printing technology is also demonstrated by the latest method developed by researchers at ETH Zurich. The Swiss team has developed a new method of robotic additive manufacturing using only clay, without the use of cement, which is a significant step towards completely sustainable construction, that is, exclusively from natural materials. It is particularly beneficial that clay is widely available, inexpensive, if not free, if the builder opts for self-excavation.
The Swiss team developed a new method with an old material and named it impact printing. It is based on the precise, rapid application of material that is colloquially described as being spat and interconnected.
The Spitting Mechanism
This ‘impact printing’ allows for faster layering of materials. In construction, the 3D printer ejects material, clay, from top to bottom, building the wall by gradually spitting the clay in smaller amounts. With each of these impacts, the material parts bond without a binding agent. This method also eliminates the need for breaks during which the material would need to harden, as is the case with traditional concrete 3D printing. This spitting is precisely the main difference compared to previous methods of 3D printing buildings, where layers are stacked on top of each other.
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3D printing in construction, also known as additive manufacturing, is a technology that began to develop at the beginning of the millennium. It is based on the application of large robotic printers to construct building structures layer by layer, most often using specially prepared concrete mixtures or other construction materials.
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In Zurich, they claim that with this method, they can eject material at speeds of up to ten meters per second. Researchers from the Robotic Manufacturing Laboratory at ETH Zurich used a mixture of excavated soil, sludge, and clay for printing in this case, which meets the necessary requirements for the stability and durability of the structure without the use of cement.
A New Tool
During the development of the technology, a special printing tool was designed that can be integrated into various high-capacity robotic platforms. This adaptability allows for application in different terrains – both in manufacturing plants and on construction sites – so experts believe that this method of construction could help conquer inaccessible terrains in the future. For now, this method can print columns and walls up to one or two stories high, while work is also underway on a robotic method for installing reinforcement that would provide additional strength to the printed structures.
TRENDSETTERS: Futuristic Technologies That Will Change the Construction Sector
When technology and ecology come together, smart ideas can be born. Of course, we are not talking about connected bottle caps and paper straws, but about truly smart new ways to preserve the Earth we live on. Since a large part of pollution is related to the construction sector, and buildings are increasingly becoming ecological, it is time for materials to become just as green, carbon-neutral, and preferably natural. Some of these futuristic technologies in construction have been simmering for a long time, and when they finally come out of the oven, they will be finger-licking good…
First, we present the so-called self-healing concrete. Concrete cracks, and maintaining and restoring concrete structures such as tunnels or buildings incurs high costs, so why shouldn’t concrete renew itself? Scientists have pondered this and believed they could extend the lifespan of concrete structures, reduce costs, and save everyone precious time. They thought and thought until they devised bacteria that produce calcite upon contact with water and seal the resulting cracks. Specifically, bacteria such as Bacillus pseudofirmus or Bacillus cohnii are added to the concrete mix with nutrients such as calcium lactate, so when water penetrates a crack in the concrete, it activates the bacteria, which then produce calcite, a mineral that fills the crack.
If you have seen ‘Star Trek 4: The Voyage Home’ with Captain Kirk at the helm, you surely know about transparent aluminum because in that film Scotty makes it, or rather creates its molecule. Once only in sci-fi films, today it is a very possible construction material. Transparent aluminum is almost as strong as steel and looks like glass. This innovation was created using laser technology and opens up new possibilities in designing futuristic-looking buildings. Made from aluminum oxynitride (AION), this transparent metal is just beginning to enter the construction sector.
Since everything today is smart, why shouldn’t roads be smart too? Green smart and networked cities simply require smart roads. You wouldn’t want to drive on a dumb road, would you? Smart roads use sensors and IoT technology for safer and more environmentally friendly driving. They record, charge electric cars, collect tolls, improve safety, gather data, send real-time information to drivers, and basically… do everything!
