3D printing is a rapidly growing technology that often captures significant hype and attention. Researchers study this technology to determine its sustainability and potential applications. By educating the public with facts and real-life examples, they make it easier to understand the positive and negative effects of this emerging field. In the construction industry, 3D printing has proven to be a sustainable technology, with high productivity rates driving its advancement.
Economic incentives for 3D printing in construction primarily stem from labor replacement. As labor shifts towards high-end construction projects, such as skyscrapers, developed countries like the US and Canada face labor shortages. This creates a target market for 3D printing in the construction of single-family homes, where cost benefits come from replacing labor and traditional masonry. A US Army Corps of Engineers analysis, based on their BEE HUT project, supports these findings.
3D printing also introduces digitalization to the construction industry, with researchers working to bridge the gap between their studies and practical applications. However, there are challenges related to sustainability when using printed concrete:
- High cement concentration in mix designs: Ongoing research aims to reduce cement content in 3D printed concrete, but changes at the material level are applicable to standard concrete as well, making shape efficiency the primary benefit of 3D printing.
- Sand: As a limited resource and key material for 3D printing, ideal sand types (river or beach sand) are not always readily available, and countries with only desert sand must import large quantities. This results in high consumption of sand and cement in 3D printing.
- Failure: Two major types of failures are strength-based failure and elastic bulking. Strength-based failure occurs when the material isn’t strong enough to support the weight of upper layers, while elastic bulking involves multiple factors such as geometry, elastic modulus, stiffness, and external forces like wind.
To improve sustainability, researchers are exploring CO2 reduction in cement production by substituting Portland cement with alternatives like fly ash, a residue from coal combustion that can enhance concrete durability and workability. However, fly ash is not sufficient on a global scale. Another potential material, called LC3 (Limestone, calcium, clay, cement), is currently under investigation for 3D printing use. LC3, created by combining clay burned at lower temperatures with limestone, functions like standard cement but produces 50% less CO2.
Research plays a crucial role in technology development, often leading to the creation of new programs and applications. Although it is difficult to predict the future of 3D printing, it is clear that there is still much untapped potential. As researchers continue to explore this technology, new opportunities and breakthroughs will likely be uncovered.