Optimizing the Utilization Rate and Performance of 3D-Printed Mortar with Dual-Size Recycled Sand

Area of Science:

• Materials Science
• Additive Manufacturing
• Sustainable Construction

Background:

• Recycled sand (RS) presents challenges in 3D printing due to variable properties.
• Optimizing RS particle size distribution is crucial for enhancing its use in construction materials.

Purpose of the Study:

• To investigate the impact of different recycled sand (RS) particle size fractions on 3D printability and mechanical performance.
• To determine the optimal RS incorporation ratio for maximizing utilization and material properties in extrusion-based 3D printing.

Main Methods:

• Material balance method for RS utilization rate calculation.
• Scanning electron microscopy (SEM) and Vickers microhardness testing for microstructural analysis.
• Bidirectional buildability tests to assess printability.

Main Results:

• Maximum RS utilization rate of 84.3% achieved with a 75% RS01 (0.075-1.18 mm) and 25% RS12 (1.18-2.36 mm) mixture.
• Optimized mixture showed improved buildability (tilt angles 7.6°/7.2°) and enhanced mechanical properties: 36.5% compressive strength, 40.7% flexural strength.
• Reduced interfacial transition zone width (46 µm) observed in the optimized mixture.

Conclusions:

• Blending specific particle size fractions of RS significantly improves its utilization and mechanical properties in 3D printing.
• The optimized mixture (75% RS01, 25% RS12) offers a viable solution for sustainable construction materials using 3D printing.
• Particle size engineering of RS is key to achieving high performance in additive manufacturing applications.