Nanyang Technological University: Processes & Materials in Large Scale Concrete Printing

Yi Wei Daniel Tay of the School of Mechanical and Aerospace Engineering at Nanyang Technological University recently submitted a thesis, ‘Large scale 3D concrete printing : process and materials properties,’ exploring the potential for more progressive techniques and materials in the construction industry.

This research examines the need for good flow in concrete ink, along with challenges in finding the correct printing parameters for performance and quality products. Ultimately, pumpability, layer adhesiveness, and buildability are critical elements as well, with all these features being explored during the fabrication of a large-scale sample—along with the option of refining the need for formwork via 3D printing.

Not only is pouring concrete in formworks for temporary support a labor intensive process, it is also more expensive; in fact, as Tay notes, formwork comprises 40 to 60 percent of the cost of a concrete frame, and ten percent of the overall building expenses.Tay realizes the benefits of 3D printing in construction:

Shorter building times
Cheaper construction
Less human labor
Reduced material waste
Greater latitude in design
Better potential for integration of functionality
“All these reductions are eventually translated to cost-saving, which compel the exploration of using 3D printing in construction for structural with customized complex geometries,” stated Tay.

Worldwide, 3D printing with concrete is garnering interest—leading to a variety of different projects and studies, from reinforcement of concrete walls to developing and using fiber additives, to experimenting with progressive new techniques. Methods for 3D printing with concrete continue to grow, to include:

Binder jetting
Material deposition method
Contour crafting
Curved-bed printing
Mesh mold
“3D concrete printing can be a complicated process, especially if the requirements are not clear. The printing parameters and material properties should be tailored to fulfil the project requirements such as cost and duration,” explained Tay. “With the printing path and speed established, the vertical loading stress can be determined. This vertical stress can be compared with the yield stress of the mixture to determine if it is suitable for printing.