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 nanofibres (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.