We are at the stage of 3D printing organs and skin tissues, hopefully creating a habitat on Mars, redesigning plane structures, and printing customized meals to consume!
All of these industries are now able to skyrocket into whole new galaxies thanks to 3D printing, but what about construction?
Let’s start by looking at where conventional construction stands.
Waste And Energy Consumption
The construction industry accounts for 40% of global energy consumption, 28% of global greenhouse gas (GHG) emissions, 12% of global potable water usage, and 40% of developed countries’ solid waste generation! As one study states, the construction industry is responsible for generating approximately 80% of the total waste in the world!
The Challenge Of Formwork
Formwork refers to the temporary additional structure or mold placed on constructions sites to keep the concrete or material in position until it sets. Formwork accounts for 80% of the total costs of concrete construction, a vivid example in the Sydney Central Business District. This is mainly because it is discarded after use and besides the cost, it also limits creativity and geometrical freedom for architects to build in various geometries. Rectilinear forms are also structurally weaker than curvilinear forms although being the most common ones.
Safety And Health
Construction is the most hazardous industry, accounting for 1 in 5 on-the-job worker deaths in the United States of America, for the calendar year 2019. The number for on-the-job injuries in construction is much more devastating. Other negative impacts inflicted upon workers and residents during construction deserve an article of their own.
Keeping it simple and honest, construction projects are usually long. Years if not months are taken up for even the more unsophisticated projects. This means continued fuel consumption, noise pollution, water pollution, and energy usage.
However, there is another major drawback. Human errors. The single biggest reason of fatalities and defects in constructions are due to human miscalculations. The construction industry had the largest number of preventable fatalities in the year 2019.
The previously mentioned Waste And Energy Consumption section provides a little insight into the results produced by unsustainable processes. In addition to that, conventional concrete made by ordinary Portland cement is not sustainable, and it’s production is very energy and carbon intensive.
Why We Need 3D Printing For Construction
More than 1.6 billion people lack adequate housing. That is more than 20% of the world!
Waste And Energy Consumption
3D Concrete Printing technologies are claimed to be significantly better in terms of reducing waste and energy consumption. In fact, this method produces almost zero waste! Going back to the fundamentals, remember that unlike subtractive manufacturing where subtracted material is discarded, additive manufacturing is the process of creating objects layer by layer from scratch. This means every bit of extruded material serves a purpose and nothing needs to be discarded because the method consists of a bottom-to-top approach, instead of top-to-bottom.
May I blow your minds away? SQ4D, an autonomous robotic construction systems company 3D printed a home, selling for half the price compared to those around the neighbourhood with similar characteristics. But that’s not even the crazy part! SQ4D says that the voltage required for their 3D printer is “about the same as a hair dryer”, having a significantly reduced environmental impact!
As previously mentioned, formwork accounts for about 80% of construction costs. However, due to the nature of the layer by layer process, formworks aren’t required. That is because concrete is being extruded layer by layer starting from the ground rather than being put in molds to dry which later have to be discarded.
Safety And Health
3D Printing concrete structures is mainly an automated process. Computer-aided designs are turned into reality using 3D printers which requires minimal physical involvement of humans, especially since traditional techniques such as placing formwork are also eliminated.
However, humans are still required to setup the printing space and be more active on the digital side of things. Certain installations such as of roofs, pipes, and windows are also jobs that current 3D printers cannot perform yet and require humans.
Efficiency Through Automation
With minimal human interference and intricate software, construction is carried out much more precisely and most errors are identified by the computer before construction begins.
Moreover, 3D printers can work continuously without needing to take breaks, unlike human labourers who need them, especially for sleeping. All that is required for most 3D concrete printing projects is supervision. This is yet another advantage of automating the construction industry.
Many companies have easily achieved the feat of printing a small house within 24 hours which speaks to the astonishing potential of the technology. But as previously mentioned before, certain jobs like installations of roofs, windows, and pipes must be performed by humans.
Researchers from the University Of Michigan developed a new technology for large-scale 3DCP using ultra-high performance concrete (UHPC). It is extruded layer by layer through an extrusion print head mounted on a 6 axes robotic arm. This allows for mechanically sounder structural constructions using layers of varying thickness, printing complex geometries without using temporary supports, and enabling multifunctionality of structural elements harnessing complex geometry.
How Does It Work
Three-Dimensional Printing, also known as Additive Manufacturing, is the process of creating products layer by layer, instead of subtractive methods. 3D Printing Concrete is a relatively new space. The technology is still being developed and has a long way to go before we see it as the primary source of construction. Here are some of the common methods for 3D printing concrete.
Fused Deposition Modelling
This is the classic material extrusion technique where materials are extruded out of a nozzle, layers stacking on top of each other. Most of the materials are in the form of filaments, such as plastic. They are heated well enough to be able to flow out of the nozzle smoothly. However, heating might not be necessary to extrude concrete out of a nozzle, but the flowability of concrete is an important factor. This is the most common method for 3D printing concrete.
Contour Crafting is a technology developed at the University of Southern California, by Dr. Behrokh Khoshnevis. The printer extrudes two layers of cementitious material to form dual standing structures, and the space between those can be filled with materials for higher strength and spaces can also be left to install pipes and wires. The goal is to use robotic arms for installations.
The printer head is put on rails, which are carefully placed on flat ground. The printer head is free to move in 3 directions; horizontally, vertically, diagonally, and is also able to operate at different heights.
Powder-Based Concrete Printing
It’s no surprise that innovations continue to happen across the globe. A team of UC Berkeley researchers have pioneered a new powder-based concrete 3D Printing technique! Rather than extruding wet cement, this method involves printing out thin layers of a special dry cement powder, each of which is then sprayed with water to harden the structure.
Things To Look Out For
With any developing technology, comes a bundle of challenges. In terms of 3D printing concrete, here are the most common ones.
Equipment Size & Cost
For 3D printing concrete, the printers have to be of a considerable size. In fact, printers may need to be bigger than the project being built in some cases, such as when using the Contour Crafting method since the rails must side outside of the printing space.
Building large printers that automate construction on a large scale also doesn’t come in cheap. Initial costs for such machinery are high, and frequent modifications can be costly.
Material Configurations and Limitations
While new material filaments are continuously being developed for 3D printing, there isn’t a large variety of materials to choose from. However, this is a little different for 3D printing concrete.
While the limitations of material choices available to print are a challenge as well, the more important issue at hand is the correct configuration of concrete that is to be 3D printed.
It is quite difficult to get the perfect consistency and characteristics of concrete so it can be easily extruded but also set in time for the next layer to be stacked on top of it. Problems such as weak bonding between successive layers, drying shrinkage, and deformation arise if sensitive requirements aren’t met. Researchers are trying to address this issue and reinforcement techniques are currently being researched. One of the possible solutions is to use fiber reinforcements to strengthen 3D concrete prints. In most cases, the mechanical properties of printable mixtures with sufficient compositions are reliable and comparable to those of mold-casted concrete. However, there is a new ray of hope with the development of Ultra High Performance Concrete (UHPC) which seems to work very well with 3D printers.
Printing materials react more powerfully when exposed to intense conditions. The high sensitivity of 3D printed concrete is commonly associated with the finer particles used compared to conventional concrete. This could lead to degradation in mechanical strength and durability, as the vulnerability to fire increases. Certain mixtures and reinforcements, such as post-treatment epoxy hardeners, glass powder, and PVA fiber-reinforcement are required to combat these challenges as newer solutions slowly develop.
Construction has always been an industry where traditional techniques are hard to replace. A few reasons of this can be identified easily.
- Testing & Certification — The challenges mentioned above must be addressed with legitimate solutions and be thoroughly tested before the mainstream use of additive manufacturing in construction. The technology requires greater attention for quicker development which includes researching solutions, testing and certification.
- Building Codes — For centuries, the world has been used to a specific style of construction, according to which specific standards and regulations for construction have been set. With an entirely new approach hitting the market, much legal work must be carried out to address the matter, which could include new building standards for additive manufacturing.
- Human Labour & Incentives — The lack of incentives to increase the efficiency of the construction industry is also a major issue. This is amplified in developing countries where cheap, low-skilled labour is readily available.
- Skills & Training — An entirely different skillset is required to take part in the new approach of construction which is challenging for many. This takes a toll on the quick adoption of additive manufacturing in the construction industry.
Winsun is a Shanghai-based company founded in 2003. Since then, it’s become one of the most famous companies in the 3D printing space and has accomplished remarkable feats.
Winsun 3D printed 10 homes in 24 hours for less than $5,000 each, a six-story apartment building, a mansion, a huge public restroom, and more!
In 2018, ICON was the first company in the United States to obtain a building permit and create a 3D printed house, which presented a strong proof of concept.
New Story is a non-profit working to provide shelter to more people in the world. The organization currently works in Mexico, Haiti, El Salvador, and Bolivia and, in just three years, has funded more than 1,400 homes for families in need. New Story is currently working with ICON to reach it’s goals.
Apis Cor is a Russian company that has developed a 3D printer that could build a house in just 24 hours, and in extreme weather conditions. According to the manufacturer, it be set up on site in 30 minutes only.
The company has created the largest 3d printed building that is located in Dubai. The building is 640 m2, reaching a height of almost 10 meters, and took a total of 17 days to print.
No wonder Dubai wants 25% of it’s buildings to be 3d printed by 2030! This staggering technology can help us construct houses and buildings much cheaper, faster, and more sustainably! The most important application that I find for this is to solve the global housing crisis, just the thought of billions of people seeing their home where they feel safe is wonderful! So many people can have temporary yet safe shelters in the face of natural disasters thanks to this technology! You can tell I’m excited!
Jaw-Dropping Into The Future
Have you ever heard of 4D printing? Well, it’s one dimension better. 4D Printing allows for 3D printed materials to change over time, triggered by certain stimuli! Such as, a web of wires can automatically become a sphere when put into water!
4D Printed Buildings
So, since the materials can change over time, buildings made of that material can too! This means buildings can develop certain characteristics when triggered by certain stimuli, such as changing it’s surface when it’s raining! How cool would that be!
Well, that’s just me wandering into the future without having anyone drag me back to the current situation. But I’m sure it’ll keep you thinking as we get closer and closer to implementing this amazing technology.
- 3D Printing has amazing potential in the construction industry.
- 3D Printing can save costs, increase sustainability, reduce project-completion times, and improve safety.
- Some current challenges to this technology include material size & cost, material configuration & limitations, exposure conditions, and various factors affecting slow adoption.
- A few companies in the 3D printing field are Winsun, ICON, New Story, and Apis Cor.
Sources & References
- Siddika, Ayesha & Mamun, Md & Ferdous, Wahid & Saha, Ashish & Alyousef, Rayed. (2019). 3D-printed concrete: applications, performance, and challenges. 9. 127–164. 10.1080/21650373.2019.1705199.
- Mohammad M, Masad E, Al-Ghamdi SG. 3D Concrete Printing Sustainability: A Comparative Life Cycle Assessment of Four Construction Method Scenarios. Buildings. 2020; 10(12):245. https://doi.org/10.3390/buildings10120245