Posted on May 07, 2019
From the time the Theatre de Marcellus was built, to the iconic high-rise skyline of New York, the art of construction has remained relatively unchanged. To date, conventional techniques such as manual labor, formwork, and traditional building mixtures are used to erect structures.
However, with the advent of technological advancements in construction automation, an observable shift has taken place in construction processes. Disruptive technologies in the face of 3D automated machines are gradually crossing over into construction industry. Although in its infancy, these machines are expected to bring housing solutions to 1.2 billion global citizens lacking access to safe and affordable accommodation.
A union of state of the art technology, machinery, and novel concrete mixtures is destined to shift the dynamics of the construction industry. Critics speculate that 3D printed concrete will soon become the preferred material of choice for building and constructions.
What Is 3D Printed Concrete?
Simply put, 3D printed concrete is a special mix of concrete, specifically prepared to flow with ease through the nozzle of the printing equipment. The structures built with 3D printed concrete are created on the fundamentals of layering, with each layer deposited on a previous layer of pumped concrete. This technique is repeated until the preferred structure emerges.
Eliminating the need for casting concrete into molds or framework, 3DCP is a cost-effective building method. The curing time of such concrete can be as low as three days, and complete structures can be constructed within hours; making it a relatively quicker and cheaper alternative to conventional construction methods.
The ingredients of the concrete mix are similar to those found in other concrete mixtures: water, cement, and aggregates like sand or stone. The success of the recipe lies in the texture and consistency itself. A workable consistency lowers the chances of pressure buildup that can block the nozzle or damage the printing equipment. Hence, for building purposes, the consistency is kept similar to that of aerated dough.
According to a previous study, almost 80% of the total waste in the world is created by the construction industry as it relies on conventional building techniques that require formwork. Compared to traditional methods, 3D concrete printing results in little to no wastage of resources, as no framework is required during the building process. The process also excludes the need for intensive labor – what’s more, complex geometric structures can be created within a tight schedule. Safe to say, 3D concrete printing offers endless potential for efficiently building bridges, houses, apartment complexes, and even barracks in active war zones.
Benefits of 3DCP
When seen in contrast to conventional methods, 3DCP has a number of advantages.
With 3DCP, architects and builders can easily inject creativity and novelty in their designs as it can be used to accurately build intricate or asymmetric designs. Varying shapes and extruded surfaces can be created on tight schedules with minimal chances of human error. This is due to the precise deposition of material with state of the art equipment.
New mixes of concrete integrated with foam display similar thermal mass capabilities to that found in traditional concrete. Further advancements in concrete mix formula similar to this can make the application of 3DCP possible for mass scale production in the future.
The construction industry is the 9th most dangerous professional space in the U.S., accounting for 21% of total deaths annually. 3DCP technology replaces the need for manual labor on worksites with automated construction. Hence, dangerous jobs which impact on-site safety of construction workers can be entirely eliminated from the construction process, such as working on heights.
Cost Effective Projects
Unlike traditional techniques, 3DCP does not require workers to manually fill molds, essentially eliminating the need for castings and frameworks. By reducing the amount of concrete required, constructors can also ensure that they stay on budget by operating on a constant rate, saving on time, material, and labor costs. Combined, these factors make 3DCP cost-effective.
The ability to construct on tight schedules also makes 3DCP a suitable solution for building accommodations during crises such as natural disasters. The development of hardened cement paste, resistant to cracking, can also increase resilience to 3D printed concrete structures, making them ideal for mass scale rehabilitation projects.
3D concrete eliminates the need for a framework, thus mitigating excessive wastage of raw materials. The printer required for 3DCP deposits a precise and specific amount of cement at a time – thus lowering CO2 emissions and ultimately our carbon footprint. This can help the industry shift towards environment-friendly sustainable practices.
Limitations and Drawbacks of 3DCP
The legal framework related to 3DCP constructions is currently limited which has created uncertainty regarding the rights and responsibilities of owners, constructors, and manufacturers.
The rules need further development on topics such as safety, social implications, the outcome on labor industry, and environmental impact. Currently, it is an unchartered territory when seen from a legal point of view.
Not Suitable For All Environments
Concrete reacts in unstable ways to higher temperatures because of its hydration process. This poses a problem when pumping concrete in smooth layers in uncontrolled weather or extreme temperature conditions. For example, 3DCP samples tested in deserts have resulted in poorer outcomes.
However, since Dubai plans to construct 25% of all its buildings through 3DCP by 2030, it is conducting extensive research on better formulas.
Limitations Due To Equipment Size
For 3DCP, printers need to be of substantial size; ideally, larger than the project being built. This may require the need for custom made printing equipment that is specific to the project.
Currently, 3DCP technology is still in the testing phase where various prototypes of formulas, equipment, and techniques are being tested. Given that equipment is the most expensive component of any 3DCP project, manufacturing automated machinery is a costly investment. Hence, for now, larger constructions with this technology are not a viable option, making 3DCP more suitable for smaller projects.
Uses of 3D Printed Concrete
According to Fox News, American Marines have completed two projects using specialized 3D concrete printers. The first project, in 2018, revolved around erecting a reinforced concrete footbridge on site. This was achieved within 14 hours, while the second project printed a 500-square-foot barracks room in less than 40 hours.
3D printed concrete is successfully being employed for military projects in the U.S and shows enormous potential for providing support to the military in active and non-active war zones.
Infrastructure & Housing
Building small sized American homes between 200 to 400 square feet can cost around $40,000 on average, while a similar sized 3D printed house may cost only $10,000. With costs expected to decrease as the technology improves, 3D printing has a lot of potential in the residential housing industry.
Single-family units can be built in less than 24 hours, whereas conventional building methods require up to 6 months. The Netherlands is now planning to build its first habitable 3D-Printed Concrete Homes with 3DCP technology. The structures will entail a mound design, much like that found on Fred Flintstone’s house. Titled Project Milestone, the first building in this project will reach completion in 2019 and will provide affordable housing to thousands of citizens.
3D concrete also has potential for constructing secure and affordable housing for poverty-stricken individuals. The Netherlands is not alone - China has successfully built a five-story apartment complex of 11,840 square foot in Suzhou. It has also created the world’s longest 3D-printed concrete bridge in Shanghai, within 450 hours.
Similarly, Dubai plans to construct 255 of its upcoming construction projects with 3DCP technology by 2030, and aims to become the hub of 3D construction.
3DCP provides many benefits in comparison to conventional methods, especially considering costs, environmental footprint and speed. Additionally, it is a better alternative for creating affordable housing after natural disasters.
In the era of technology, construction companies must remain on top of trends and innovations to be able to offer the best solutions. Want to learn more about different types of concrete? Contact us today!