Wood-Waste-Based Artificial Aggregates for Extrusion 3D-Printed Cementitious Composites: Hydration, Printability, and...

Area of Science:

• Materials Science
• Construction Engineering
• Sustainable Materials

Background:

• Wood-based waste presents a challenge due to its potential to retard cement hydration.
• Developing sustainable construction materials is crucial for reducing environmental impact.
• Three-dimensional (3D) printing offers novel possibilities for creating complex structures with cementitious composites.

Purpose of the Study:

• To investigate the feasibility of using chemically modified wood-based waste as artificial aggregates in 3D printable cementitious composites.
• To evaluate the impact of these aggregates on cement hydration, microstructure, and mechanical performance.
• To assess the potential for creating more sustainable 3D printed construction materials.

Main Methods:

• Wood dust was chemically modified with a calcium nitrate-based accelerator and granulated into artificial aggregates.
• Aggregate mechanical robustness was characterized.
• Cement hydration and microstructural development were analyzed using X-ray diffraction (XRD) and thermogravimetric/differential scanning calorimetry (TG/DSC).
• Modified aggregates were incorporated into 3D printable cementitious mixtures to evaluate fresh-state properties, printability, and mechanical performance.

Main Results:

• The chemical modification and granulation produced aggregates with sufficient crushing resistance.
• The modified aggregates influenced cement hydration by increasing bound water content and altering hydration products.
• Incorporation of aggregates led to reduced compressive and flexural strengths compared to the reference mixture.
• A significant reduction in the difference between mechanical properties in different loading directions was observed, indicating more uniform structural response.

Conclusions:

• Chemically treated wood-based aggregates can be successfully integrated into 3D printable cementitious systems.
• This approach offers a viable pathway toward developing sustainable construction materials using waste products.
• While mechanical strength may be reduced, the improved uniformity of printed elements presents a notable advantage.