3D printing is a very fast-rising technology that is gaining more and more space across different manufacturing sectors, including the construction industry, where this technology was first introduced in the 1950s. Since then, 3D printers and the related material mixtures used in construction have become increasingly efficient, cost- and time-effective, and environmentally sustainable. Modular 3D printing (M3DP) and advanced materials can help achieve these goals.
3D printing technology, also known as additive manufacturing, is emerging as a future player in construction practices, with estimates suggesting that this industry will reach the 36-billion-dollar mark by 2025. In this context, more and more companies operating in 3D printing have begun to focus on modularity, (i.e., the construction of buildings composed of modules prefabricated separately in an off-site factory and assembled on-site). This construction process has several benefits, not only for the industry, but also for society and the environment, with a potential ripple effect.
The benefits of modular 3D printing for construction companies
Modular construction began to emerge among 3D printing operators primarily in response to the COVID-19 crisis: worker-to-worker spacing requirements and construction site closures imposed by national health policies severely limited or prevented on-site work and the use of traditional construction techniques. At the same time, the crisis also caused raw materials shortages or delays in delivery due to supply chain disruption throughout industries. In this context, the combination of modularity and 3D printing lent itself to be a very promising solution to a problem that was bound to persist even after the height of the pandemic, as it allowed individual prefabs to be printed off-site and assembled at a later date, with faster and more flexible timelines, with less material needed, and far fewer workers required.
These advantages of modular 3D printing have triggered a trend for companies to favor this construction technique as it is much more flexible in design, customizable, fast, material- and cost-efficient than traditional construction, and capable of creating a more resilient industry in the event of future disruptions and global emergencies.
The benefits of modular 3D printing for society
Future demographic projections point to a trend that will continue to consolidate in the coming decades: the unstoppable drive toward urbanization. This means that more and more people will concentrate in urban centers, with estimates suggesting that by 2050 about 68 percent of the world’s population will live in cities. Geographically, this phenomenon affects poorer segments of the population in developing countries the most, but developed countries will also be profoundly affected.
In this context, speed and efficiency in construction, malleability, and the possibility to expand the number of rooms, become the key elements to meeting a growing demand for housing in cities. Modular 3D printing can fulfill these needs while achieving increasingly lower costs in the long run.
Expandable and malleable houses
Modular 3D printing makes it possible to create houses quickly and efficiently using the 3D printing technique and with great potential for expansion due to modularity: depending on requirements, new modules can be added when needed to extend the living space. In addition, different modules can be reassembled in different ways. This allows for a dwelling that can better adapt to the number of tenants and their affordance.
Decent and affordable housing
The affordability of a house depends on construction costs, the cost of labor, and the materials used. Through 3D printing, construction costs can be reduced by about 35 percent through increased efficiency. In addition, the cost of labor is also reduced since fewer workers are needed. Although the cost per worker increases (due to the demand for more advanced or new skills and training) it is still cheaper for a company than traditional construction. The amount of materials used is also reduced by about 40 percent. At the moment, the cost of materials for 3D printing is higher than conventional ones, but it is estimated that there will be a gradual and significant reduction in cost as new more durable, highly-performant, and environmentally sustainable material mixtures are developed.
The benefits of modular 3D printing for the environment
The construction sector is a major source of pollution and resource depletion on our planet, responsible for over 30 percent of global CO2 emissions, raw material extraction, energy, and water consumption. As urbanization increases, these estimates are also likely to rise. This is one reason why, as part of the ambitious global sustainability goals, this sector is encouraged to move away from “tradition,” and explore new techniques and new construction materials.
Modular 3D printing enables a sustainable approach from the beginning to the end of the construction process. The prefabricated modules are printed and already partially assembled in the off-site factory, where work is faster because it is not constrained by potential delays (e.g., waiting for materials to arrive on-site at the appropriate time) or disturbed by external factors that would force operations to be suspended or slowed down. This leads to reduced emissions and lower energy consumption already in the construction and assembly phase. Off-site 3D printing also enables printing more insulating and finished modules than with traditional techniques. This allows future tenants to reduce energy consumption and pollution from heating and air conditioning.
Unlike traditional construction sites that can generate tonnes of waste, 3D printing of prefab produces no waste. Another benefit for sustainability is the wide range of environmentally friendly and bio-based mixes that can be used as printing materials. For example, the Italian 3D printing company WASP, in collaboration with architect Mario Cucinella, has printed eco-sustainable and easily transportable modules conceived primarily for developing communities, using a mix of soil from northern Italy. The same company also works with a mixture composed mainly of rice waste. In collaboration with the Dior corporation, it printed two pop-up stores in Dubai using this mix while producing zero emissions.
In addition to supporting sustainability goals, bio-based mixes also allow new ways of using locally abundant materials. This reduces the need to import materials from third countries and thus reduce the production costs. In the long term, this could allow different regions to become more independent in terms of resources.
From conventional materials to ‘secret recipes‘
Mixtures created for 3D printing in construction can be employed differently depending on the purposes or the performance desired from the printed construction. It is no coincidence that with the gradual global adoption of modular 3D printing, many companies have begun to invest in R&D to acquire proprietary mixtures (i.e., ad-hoc recipes of combined materials – some kept secret). This allows them to generate printing mixtures with well-defined properties depending on the purposes of the projects: Some may be optimized for building sustainable and eco-friendly houses – as in the case of WASP – while others are resistant to extreme climatic factors such as tornadoes, or even designed to be used on the moon.
D-Shape is one of the companies that employ unusual mixes that go beyond metal and different variations of concrete. A pioneer in the use of a sand-based mix, the company built a house using a sand-binding technique. This provided it with significant strength, preventing it from being blown or washed away. This mixture and the accompanying technique, first presented in 2010, have since attracted increasing interest among 3D printing practitioners, and are likely to see further use in the future.
Another interesting example is that of a mortar-based mixture (i.e., a mixture similar to concrete with the addition of lime), which is already used in traditional construction as a binder between brick layers. Its greater malleability compared to concrete allows for less clogging of nozzles and errors between layers during printing. Companies such as Laticrete are the leading producers of mortar, specifically adapted in its composition to be optimized for 3D printers.
Finally, there are mixtures based on lunar soil. Advances in space exploration have led many companies to think about printing constructions that would be ideal for the moon – or other planets – using local soil. Icon, for example, a construction technologies company based in Austin, creates 3D-printed prototype elements based on lunar materials that, when completed, could grant the company direct testing on the moon’s surface, as part of an upcoming project aimed at implementing a full-scale additive construction system. Similarly, AI SpaceFactory and the NASA Kennedy Space Center are engaged in the creation of LINA, an entirely 3D-printed structure made of a mix of terrestrial polymers and lunar regolith that will serve as a base to support astronauts. The goal is to make the structure more resistant to lunar-specific issues, such as radiations, thermal oscillations, and seismic activities.
‘One small step for a man, one giant leap for mankind‘
3D printing in construction is moving toward a future in which this technique and the related material mixtures will acquire a predominant role in the construction sector. This will allow for reduced costs, higher speed, and resilience, and will sustainably accommodate the demands of an increasingly urbanized society.
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