Know About 3D Printed Concrete

It's no surprise that firms are looking into adopting 3D printing in building now that 3D printing devices are readily available for domestic usage. Concrete 3D printers, in particular, have been steadily gaining favor among architects and construction companies. Despite their beginnings, these are projected to provide housing solutions to the 1.2 billion people worldwide who do not have access to safe and cheap homes.

This article will cover 3D-printed concrete, its uses, processes, advantages, limitations, and some examples of structures that have been constructed with it so far.

Fig 1: A 3D Printing model in construction Courtesy: 3D Printing Industry

What is 3D Printed Concrete?

3D printed concrete is a type of concrete that may be placed layer by layer using a 3D printer without formwork or a vibration process. The foundations of 3D printed concrete house constructions are layering, with each layer deposited on top of a previous layer of pumped concrete. This process is repeated until the desired structure appears.

The concrete mix contains the same materials as regular concrete mixes: water, cement, and aggregates such as sand or stone. The texture and consistency of the dish are crucial to its success. Pressure buildup, which can block the nozzle or harm the printing equipment, is less likely with a working consistency. As a result, the consistency is retained comparable to that of aerated dough for construction purposes. Workability, setting and hardening time, and mechanical qualities are just a few critical performance indicators that can be improved with the right materials and printing parameters.

How are Structures Built with it?

A typical concrete 3D printer uses a robotic arm with one end attached to the printhead and the other to a gantry or crane-like robotic arm system to additively create things through material extrusion. This printer deposits materials like concrete layer by layer through a nozzle.

Concrete must lose a large portion of its flexibility to maintain the printed shape shortly after printing. On the other hand, concrete should not solidify too quickly to allow layers to cling to one another. If the layers are stacked on top of one another with no strong connections between them, the structure will be weak and have no tensile strength. This means that we won't be able to utilise regular concrete in 3D printing. Instead, a special type of concrete will be required.

What are the Advantages of 3D Printed Concrete?

3D Printed Concrete offers many advantages, some of which are:

● Environment Friendly

The manufacturing of regular Portland cement results in considerable carbon dioxide emissions and other greenhouse gases. The cement sector is responsible for around 8% of all carbon dioxide emissions in the atmosphere. In such a case, limestone can be used as limestone is less toxic and has a lower environmental impact than Portland cement throughout the manufacturing process. It can be used in concrete for 3D printing instead of standard Portland cement without lowering the quality of the printing mixture.

● Budget-friendly in the long run

3D printing incurs additional carriage and assembly costs that the customer must bear during off-site construction. The cost savings of on-site 3D printing are much more likely to be passed on to the new homeowner because the construction company can maintain a healthy profit margin despite the overall cost reduction. Also, it is interesting to note that 3D printing is being used by aviation companies such as Boeing, Rolls Royce, and Pratt & Whitney to create metal parts, mostly for jet engines. It can be less expensive than machining metal blocks, and the complicated components are often lighter than their traditional counterparts.

● Time-Saving

A 3D printed house, including complete finishing and furniture, might take only a few days using on-site 3D construction printing. The absence of transportation lag periods means less burden for the building 3D printing company. Thus, these time savings are directly passed on to the consumer. That means there will be more opportunities to 3D print more houses rather than having a backlog of orders to ship and build.

Are there any Limitations with 3D Printed Concrete?

Unfortunately, yes.

Making molds is one useful application for 3D printing in construction. Mould creation is usually a challenge in sophisticated precast projects since it necessitates a lot of labour and precision. The technique becomes easier and needs less labour if the moulds are 3D printed.

Moreover, economic viability is one stumbling block for 3D printing technology. This technology will not be extensively embraced unless there is a clear economic gain at some point in the future. As a result, manufacturers may want to consider broadening their business model.

Structures built with 3D Printed Concrete

Some of the structures that have been erected with 3D Printing are:

● Dubai's Warsan building holds the Guinness World Record for the largest on-site 3D printed structure. The construction was 3D printed on-site using mineral-infused fluids that solidify into concrete, eliminating the need for any additional assembly labour. The structure stands 9.5 metres tall, covers 640 square metres, and was built entirely of local materials.

Fig 2: World’s Largest On-Site 3D Printed Building Courtesy: 3D Printing

● Shanghai Pedestrian Bridge

In the industrial and creative core of Shanghai's Baoshan district, the world's largest pedestrian bridge 3D printed entirely in concrete was completed at the start of 2019. Professor Xu Weiguo of Tsinghua University's School of Architecture led a team that developed and led the project.

Fig 3: World’s longest 3D printed pedestrian bridge Courtesy: CNN

●The Department of Energy's Oak Ridge National Laboratory (ORNL) developed the Additive Manufacturing Integrated Energy (AMIE). It's a solar-powered structure linked to a hybrid electric vehicle, forming a complete energy system. During the day, solar panels supply energy to the vehicle, while the 3D printed vehicle provides energy to the residence.

Fig 4: AMIE Courtesy: Architonic

Conclusion

Concrete 3D printing has the same challenges as other businesses that use the technology. It takes time to develop new technology. It's a matter of figuring out specifics and making all of the many elements work. Concrete constructions printed in 3D will most likely become more common in the future. We can't say what shape it will take in the construction industry right now.

References

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● 3D printed house: 20 most important projects. All3DP. (2021, January 28). Retrieved May 2, 2022, from https://all3dp.com/2/3d-printed-house-3d-printed-building/

● “Dubai Unveils World’s Largest On-Site 3D Printed Building.” 3D Printing, 3dprinting.com, 25 Oct. 2019, https://3dprinting.com/construction/dubai-unveils-worlds-largest-on-site-3d-printed-building/.

● “How 3D Concrete Printing Is Paving the Way for Construction - GrabCAD Blog.” GrabCAD Blog, blog.grabcad.com, 27 June 2019, https://blog.grabcad.com/blog/2019/06/27/3d-concrete-printing/.

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● “A Review of the Current Progress and Application of 3D Printed Concrete.” A Review of the Current Progress and Application of 3D Printed Concrete - ScienceDirect, www.sciencedirect.com, 17 July 2019, https://www.sciencedirect.com/science/article/abs/pii/S1359835X19302829#:~:text=3D%20printed%20concrete%20is%20a%20special%20type%20of%20concrete%20that,concrete%20and%20self%2Dcompacting%20concrete.

● “How Does a Concrete 3D Printer Work? - 3Dnatives.” 3Dnatives, www.3dnatives.com, 8 Jan. 2021, https://www.3dnatives.com/en/how-does-a-concrete-3d-printer-work-080120215/#!

● “What Is 3D Printed Concrete? Can It Change The Construction Industry….” Specify Concrete, www.specifyconcrete.org, https://www.specifyconcrete.org/blog/what-is-3d-printed-concrete-can-it-change-the-construction-industry-as-we-know-it. Accessed 2 May 2022.

● “3D Printing Gets Bigger, Faster and Stronger.” 3D Printing Gets Bigger, Faster and Stronger, www.nature.com, 27 Apr. 2022, https://www.nature.com/articles/d41586-020-00271-6.

● “3D-Printed Concrete: Still in Its Infancy - Elematic Precast Technology.” Elematic Precast Technology, www.elematic.com, 30 Mar. 2021, https://www.elematic.com/concrete-issues/3d-printed-concrete-still-in-its-infancy/.

● Chougan, Mehdi, et al. “Future Cities Could Be 3D Printed – Using Concrete Made with Recycled Glass.” The Conversation, theconversation.com, 28 Feb. 2022, https://theconversation.com/future-cities-could-be-3d-printed-using-concrete-made-with-recycled-glass-175598.

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