Rheological Properties and Mechanical Response of Bio-Based Graphene Enhanced Additively Manufactured Cementitious Composites (2025-12)¶

This research characterizes the influence of graphene nanoplatelets (GNPs) on the rheological properties and mechanical response of additively manufactured cementitious composites using a screw-type printing mechanism. Cementitious composites were reinforced with bio-based GNPs at 0.025 %, 0.05 %, 0.10 %, 0.15 %, and 0.20 % of the weight of the binder. The rheological properties of the bio-based GNP-reinforced cementitious composites were evaluated using a rheometer in terms of the static and dynamic yield stresses, plastic viscosity, and storage modulus. Additionally, compressive, tensile, and flexural specimens were additively manufactured and tested in two main configurations, parallel and perpendicular to the printing direction, alongside cast-in-place control samples to evaluate the anisotropic response of the 3D printed specimens. Rheological test results indicated that incorporating bio-based GNPs had minimal influence on storage modulus, while 0.20 wt% GNPs increased the static yield stress by 55 % compared to the control mixture. In terms of mechanical response, the average compressive strength of 3D printed specimens containing 0.10 wt% GNPs increased by 106 % and 90 % for specimens with filaments oriented perpendicular and parallel to the printing direction, respectively, compared to 3D printed control specimens. Besides, the addition of bio-based GNPs enhanced the tensile and interlayer bond strengths of the additively manufactured cementitious composites by up to 55 %. Also, the average flexural strength of 3D printed GNP-reinforced cementitious composites consistently exceeded that of the printed controls in both loading directions, with perpendicular loading showed up to a 46 % improvement, demonstrating enhanced interlayer bonding and reduced anisotropy. An optimal GNP content of 0.10 wt%–0.15 wt% provided a balanced rheological profile, enabling smooth extrusion, improved buildability, and superior mechanical performance. SEM analysis also confirmed that optimal GNP contents refined pore structure and promoted C–S–H nucleation, forming a denser matrix, whereas higher contents led to agglomeration and reduced strength. Finally, cradle-to-gate life cycle assessment demonstrated that incorporating bio-based GNPs reduced the global warming potential, confirming their contribution to enhanced structural performance and overall sustainability.