Additive Manufacturing of Carbonatable Ternary Cementitious Systems with Cellulose Nanocrystals (2025-09)¶

Production of carbonatable cementitious materials (CCMs) using mineral carbonation is a sustainable approach for alleviating CO2 emissions from the production of cement. With the rapid advancement of concrete 3D printing, developing 3D-printable CCMs is crucial for sustainable construction. However, previous studies on millimeter-scale single-binder 3D-printed CCMs face limitations due to size constraints, material shortages, and inconsistent performance across different geographic regions. This study addresses these challenges by developing ternary binder CCMs incorporating wollastonite, hydrated lime, ordinary portland cement, and ground granulated blast furnace slag, along with cellulose nanocrystals (CNCs) to enhance fresh and hardened properties. The obtained results demonstrate that CCMs achieve 60 %-70 % carbonation within 14 days, with flexural strength comparable to control OPC samples (≈8.5 MPa), while CNCs further improve strength by 25 %. CNCs also improve extrudability and buildability, reducing the need for chemical admixtures. The results from life cycle assessment indicate that the developed 3D printed CCM systems achieve a 30–65 % reduction in global warming potential compared to 3D printed OPC mixtures.