MATERIALS USED FOR 3D PRINTING CONSTRUCTION makenica.com/materials-used-for-3d-printing-construction September 21, 2020
3D printing technology has grown tremendously in recent years. It has revolutionized the workings of many industries. Additive manufacturing is now being widely used in the construction industry as well. Thanks to this technology, the construction industry can exercise better creativity, design flexibility, low wastage of materials, more robust structures and lesser carbon footprint. Using 3D printing for construction, many wonderful and innovative projects have been developed. Several architectural and construction firms are adopting 3D printers to design and construct buildings. But what are these structures made up of? What is the material being used to 3D print buildings? This article will answer such questions in detail.
WHAT ARE THE MATERIALS BEING USED FOR 3D PRINTING IN CONSTRUCTION INDUSTRY? Additive manufacturing is all about the material. Depending on its application, the type of material used for 3D printing changes. For structural applications, basic material like 1/4
cement, sand and other additives is required. However, while 3D printing, some extra variants are also used. The exact recipe of the mix depends on the purpose as well as the 3D printer. To understand this more clearly, we will look at some real-life examples of construction with 3D printing. BUILDING ON DEMAND IN COPENHAGEN (COBOD) COBOD is a European start-up company that uses 3D printing for construction. In 2017, this company was responsible for 3D printing the first building in Europe: The Building On Demand (BOD). All the elements in BOD are completely curved except the straight doors and the windows. Even the foundation of this building was 3D printed. COBOD's used a construction printer capable of working in three dimensions so that it can access any position within the envelope. The printer was also used as an on-site 'crane' to place certain elements into the building. In collaboration with FORCE technology, COBOD developed a strong and sustainable concrete mix using recycled material. They used a mixing pump that automatically filled dry material mix from the mixer. After this, water was added to the mix to keep the pump filled. Material used: Concrete mix consisting of cement, sand and other additives. WASP: GAIA WASP is an Italian start-up company that uses local materials to construct 3D printed sustainable houses at an affordable price. They used their vision to 3D print an ecosustainable house, the Gaia. It is the first 3D printed mud house made from naturally available materials. The 3D printing of this earthen structure used a material mix consisting of soil, lime and rice fibres. The mix was made homogeneous and workable by mixing it thoroughly in a wet pan mill. The extrusion was done by a Crane WASP 3D printer. Finishing was done by shaving clay lamina on a monolithic wall. It was then smoothed and oiled with linseed oils. Material used: Natural material mix consisting of 25% soil, 40% straw chopped rice, 25% rice husk, and 10% hydraulic lime. TVASTA: ROOM MODULE Tvasta is an Indian start-up company that aims to provide quality construction to make affordable and sanitary homes available to people in the remote parts of the country. 2/4
It is the first company to build a concrete 3D printed structure in India. Tvasta, in collaboration with IIT Madras, created a specialty concrete that was affordable as well as sustainable. It is like the basic portland cement but with a lower water-cement ratio. Amorphous metal fibres or plastic fibres are used along with the cement, based on the application. The structure made by them has 12 mm rebar on all four corners for secure attachment. It is also present in the hollow sections of the structure to provide tensile strength. The structure was specifically designed and 3D printed with hollow sections so that while wiring and plumbing, the walls are not damaged. Material used: Concrete mix based on ordinary portland cement, but with lower water-cement ratio and consisting of cement, sand, and other additives. APIS COR: RESIDENTIAL HOME Apis Cor is an American start-up company based in San Francisco. They are dedicated to developing mobile 3D construction printers capable of printing structural components like self-supporting walls and partitions. They were successful in 3D printing a house in a suburb in Moscow in just 24 hours. They have developed their own material mix for 3D printing. This concrete is extrudable and consists of sand, cement, geopolymers and, fibres. The final mix is prepared by mixing all the materials in a big hopper. The extruder receives this mix through a pump system and then deposits it. The structural components are 3D printed on-site with a printer that has an independent robotic arm. A small gap was left between the interior and exterior of the walls of the house. Fibreglass reinforcements were placed in this space. In addition to this, a Polyurethane-based mixture was sprayed in the gaps to insulate them. After 3D printing the walls, a crane was used to remove the printer for installing windows, appliances and a roof. Material Used: Concrete mix made up of cement, sand, geopolymer, sand and other additives. WINSUN: WAVE BUILDING Winsun is a Chinese start-up company that started as a supplier of building materials but soon developed their own 3D printer. Their 3D printer is capable of constructing large scale buildings at a high speed. They took the 3D printing construction market by storm when they printed ten houses within 24 hours! The components are printed off-site in a factory and then transported and assembled on-site.
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Along with the printer, they have developed their own material mix which is environmentally friendly and produces zero waste. Material used: Concrete mix made up of cement, sand, fibre and other additives.
CONCLUSION Although the material is a crucial factor in determining the structure's quality, the ability of architects and strength of designs and machines is also important. 3D printing services has provided a faster, cheaper, and more sustainable alternative of construction to the world. Continuous research is being carried out to develop better materials for use in 3D printing of structures. The most common material in use, for now, is a concrete mix made out of cement, sand and other additives. However, companies like WASP have succeeded in developing earth-based materials as well. The options will surely continue to grow. Happy House Printing!
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