Imagine concrete extruded from a computer-controlled nozzle, rather like an enormous pastry icer “building” a layer cake. This is how 3D concrete printing (3DCP) works. It’s real and it has the potential to lower construction labor costs, time and materials waste. As the technology continues to advance, it also offers the possibility of greater design flexibility via the creation of complex geometries that would be difficult or impossible with traditional formwork.
The process already is being used by a major retail player: Walmart recently leveraged Alquist 3D technology to construct a nearly 8,000-square-foot, 20-foot-high addition to its Athens, Tenn. store for the retailer’s online pickup and delivery program.
“This is the first such facility of its kind and it’s just incredible that it is a reality; this is going to play a major role in the advancement of 3DCP technology,” said Zachary Mannheimer, Founder and Chairman of Alquist 3D in a statement. “And for Walmart to see the value in the project demonstrates how forward-thinking the leadership of this organization is.”
Not Yet Ready for Prime Time
However, construction industry experts noted that 3DCP technology, while advancing rapidly, still has a number of limitations that have kept its use confined mostly to residential buildings. In addition to high initial investment costs for the technologies themselves, “there are limitations in terms of the maximum building size and height that can be achieved with current technology,” said Julie Hyson, Americas Portfolio Clients, Services and Industries Lead at commercial real estate firm JLL in an interview with Retail TouchPoints.
“The process can be sensitive to environmental conditions, affecting concrete curing and layer adhesion,” Hyson added. “There are also challenges related to integrating traditional building components (like windows, doors and utilities) into 3D-printed structures. The technology is still evolving, which means there’s a lack of standardization and established building codes specifically for 3D printed structures.”
New Design Possibilities on the Horizon
But 3DCP certainly seems to be on the growth fast track, moving from an R&D phase during the 2000s to initial practical applications by the mid-2010s in China, the Netherlands and now the U.S., according to Matt Abeles, VP, Construction Technology and Innovation at ABC (Associated Builders and Contractors), an industry trade group.
“The most interesting advancement in 3D concrete printing is going from printing under-350-square-foot homes to printing a multistory apartment complex in the span of three years,” said Abeles in an interview with Retail TouchPoints. “Also, thanks to the uptick in research and development funding, we are seeing advances in the use of sensors to monitor concrete properties in real time, new nozzle designs and even concrete mixes that utilize carbon fibers.”
Hyson agreed that technology advances are happening on multiple fronts. “There are improved material formulations for better strength and durability, multi-material printing capabilities, integration of reinforcement methods (such as embedded steel bars and fiber reinforcement) and large-scale printers capable of producing larger buildings,” she noted. “Additionally, advancements in software and control systems have enhanced precision and allowed for more complex geometries, and there’s a lot of concentration on refining the aesthetics, for example, the smoothness of the finishes.”
Speaking of aesthetics, 3DCP has the potential to give designers new and customizable construction elements. “3DCP allows for the creation of complex, organic shapes and intricate geometries that would be difficult or costly with traditional formwork,” said Hyson. “This enables architects to explore new aesthetic possibilities and functional designs.
“The technology also facilitates the integration of multiple functions into a single element, such as combining structural, insulative and aesthetic features,” Hyson added. “It allows for precise control over internal structures, enabling the creation of optimized, lightweight designs.”
Cost Savings, Green Impact Still TBD
Given 3DCP’s relative novelty, it’s too early to determine if this construction method will be less expensive in the long run. Additionally, its net impact on sustainability remains to be determined.
A reduction in wasted construction material could be key to both prospective benefits. “The benefits of 3DCP include reduced costs, less complex construction schedules (or less activities/definable feature of work if speaking in terms of project management) and less materials waste,” said Abeles.
“The process minimizes material waste, as it uses only the necessary amount of concrete,” said Hyson. “It also can potentially improve building performance through optimized designs for thermal insulation and structural efficiency. Additionally, the precision of 3D printing can lead to improved quality control and consistency in construction.”
As for 3DCP’s sustainability bona fides, they are, you guessed it, complicated. “Green challenges may include high cement content (cement production is still a major carbon dioxide contributor), 3D printers’ high energy consumption and the longevity and durability of alternative materials,” said Abeles.
Some mixes for 3D printing “incorporate recycled materials or alternative binders that can significantly reduce environmental impact,” said Hyson. “Overall, while 3D concrete printing has the potential to be more sustainable, its ‘green’ credentials depend on how it’s implemented and the specific materials used.”
Even if 3DCP is not quite ready for the big time, there are a number of other unconventional building materials that architects and retail designers can deploy, according to Abeles, such as “mass timber (overall structure or stand-alone stair towers or elevator shafts), modular off-site construction (more familiar and recognized, but with room to grow), pre-cast stair towers and elevator shafts.” Hyson also mentioned hempcrete, which features low mechanical properties and low thermal conductivity, making it good insulation material, although it’s not considered strong enough to be load-bearing.