Chloride Diffusion by Build Orientation of Cementitious Material-Based Binder Jetting 3D Printing Mortar

Area of Science:

• Materials Science
• Civil Engineering
• Additive Manufacturing

Background:

• Binder jetting 3D printing (BJ3DP) offers high geometric freedom for architectural designs.
• Structural applications of 3D printed concrete necessitate evaluation of mechanical properties and durability.
• Chloride penetration is a critical factor affecting the long-term performance of concrete structures.

Purpose of the Study:

• To evaluate the compressive strength and chloride diffusion durability of cement-based 3D printed materials.
• To investigate the influence of build orientation on the mechanical performance and durability of BJ3DP concrete.
• To provide insights for optimizing the design and manufacturing of durable 3D printed structures.

Main Methods:

• Cement-based materials were 3D printed using binder jetting technology.
• Compressive strength tests were conducted along the build and transverse directions.
• Chloride ion penetration tests were performed to determine diffusion coefficients in different orientations.

Main Results:

• Compressive strength was 22.1–26.5% lower in the transverse direction compared to the build direction.
• Chloride diffusion coefficient was 186.1–407.1% higher in the transverse direction than in the build direction.
• Build orientation significantly impacts both mechanical strength and durability against chloride ingress.

Conclusions:

• BJ3DP concrete exhibits anisotropic properties, with reduced strength and durability in the transverse direction.
• Careful consideration of build orientation is crucial for designing and manufacturing durable 3D printed concrete structures.
• Further research into optimizing printing strategies is needed to mitigate directional performance differences.