STRENGTH IN THE CURL: Leveraging Bending Instability for Structural Performance and Carbonation in 3D-Printed Calcium Silicate Cement

Abstract

This senior thesis explores how 3D printing-induced buckling can enhance both the mechanical Strength and carbonation potential of calcium silicate-based cement. I did so by using a wollastonite-based binder and a cement printing setup. I designed and printed six different architectural sample types: Cast, Laminar, Cellular, Coiling, Alternating Loop, and Meander.

The goal was to test how the formation of different samples using different instability ratios changed and affected the internal geometry and from this its impact on structural performance and CO2 absorption. After letting the samples cure in a controlled carbonation chamber, samples were evaluated through three-point bending and phenolphthalein tests to assess both flexural Strength and carbonation. Results showed that printed samples carbonated fully within 72 hours, while cast samples were still uncarbonated in the center. Mechanically, Cellular samples performed best in both Modulus of Rupture (MOR) and energy absorption, while the Coiling and Meander samples showed promising ductility and stress redistribution after failure.

These results highlight the potential of architected geometries to make cementitious structures both stronger and more sustainable. By changing printing patterns and leveraging instabilities like coiling, we can design structures that naturally sequester more CO2 while outperforming conventional forms in strength and toughness.