3D Printable Mortars With Green Materials: Sustainable Solutions With Nanocellulose

This study aims to improve the fresh and hardened properties of 3D-printable mortars. For this purpose, mortar mixtures containing cellulose nanofibers (CNF) obtained from the green algae of the Cladophora sp., which is abundant in lakes and causes environmental pollution if not recycled, as well as commercially available cellulose nanocrystals (CNC) and welan gum (WG) were prepared. The results showed that CNF was the most effective additive in improving fresh-state rheology, increasing yield stress by approximately 6 times and thixotropy by 48 times compared to the reference sample. Additionally, the CNF-modified mortar could carry a load of 50 N in the fresh state. The CNC additive showed the best mechanical performance, increasing compressive strength by 12%. Cellulosic additives were also observed to reduce shrinkage. Nanocellulose additives also increased the interlayer adhesion strength. All additives used have improved the properties of 3D-printable mortars. This study successfully produced a 3D-printable concrete/mortar additive from Cladophora sp., an environmentally detrimental waste material.

本研究旨在提升可3D打印砂浆的新拌与硬化性能。为此，本研究制备了掺加三种外加剂的砂浆拌合物：从湖泊中大量富集、若未回收便会造成环境污染的刚毛藻属（Cladophora sp.）绿藻中提取的纤维素纳米纤维（cellulose nanofibers, CNF），以及商用纤维素纳米晶体（cellulose nanocrystals, CNC）与威兰胶（welan gum, WG）。研究结果显示，相较于基准试样，纤维素纳米纤维（CNF）是改善新拌流变性能最有效的外加剂，可将屈服应力提升约6倍，触变性提升48倍；且掺加CNF的砂浆在新拌状态下可承受50 N的荷载。商用纤维素纳米晶体（CNC）则展现出最优的力学性能，可将抗压强度提升12%。此外，纤维素类外加剂可降低砂浆收缩变形，纳米纤维素类外加剂还能提升层间粘结强度。本次研究所使用的全部外加剂均改善了可3D打印砂浆的各项性能。本研究成功以对环境有害的废弃物料刚毛藻属（Cladophora sp.）为原料，制备出可应用于3D打印砂浆的外加剂。