Abstract
This dissertation presents a comprehensive framework for the additive manufacturing (AM) of high-fraction wood-thermoset composites for construction by integrating system development, rheological characterization, and curing optimization into a singular predictive engineering model. Initially, a continuous-flow processing system was developed using a novel inline mixing method to produce a wood-sodium silicate composite (WSSC) at a 50:50 fiber-to-resin mass ratio. The homogeneity of the WSSC was validated through bulk density analysis, near-infrared (NIR) spectroscopy, and micro-CT scanning, while compressive strength and dimensional stability tests confirmed the materials structural viability. The feasibility of the framework was demonstrated through the successful extrusion of a large-scale, two-step structural staircase prototype. To move beyond empirical observation, the underlying physical mechanisms governing the extrusion process were characterized through targeted rheology. This study validated high processing speeds at room temperature and identified a significant disconnect between the materials static yield stress (0.13 MPa) and flowing yield stress (5.14x10-6 MPa). While continuous flow rules were insufficient, the Carreau-Yasuda model successfully described the material behavior, proving a foundational template for scaling. Time-dependent shear and creep-recovery tests further confirmed a processing window of at least 300 s with a 58 % thixotropic recovery efficiency, establishing a foundational template for scaling wood-fiber deposition beyond empirical trial and error. Finally, the impact of moisture-dependent curing on interlayer adhesion and secondary assembly was investigated. Mechanical fastener pull-out strength was evaluated across five curing levels, identifying a critical threshold at 60 % moisture loss for reliable structural stability. Conversely, interfacial shear, splitting tensile, and direct tensile testing revealed that the degree of curing between successive layers had no statistically significant effect on bond strength. These findings indicate that while moisture loss is a limiting factor for mechanical fastening, the inherent structural adhesion of the material remains robust across a broad temporal window. Together, these studies provide the technical and scientific foundation necessary for replacing traditional concrete with sustainable, bio-based composite in complex structural applications.