Performance assessment of limestone-reinforced calcium aluminate cement in binder jetting 3D printing: Mechanical properties, microstructure, and hydration

초록

This study systematically elucidates the synergistic mechanisms whereby limestone (LS) regulates the hydration processes, microstructural evolution, and mechanical performances of calcium aluminate cement (CAC)-based binder jetting 3D printing (BJ3DP) materials. LS not only optimizes the powder-bed characteristics and enhances the uniformity of binder penetration and dimensional accuracy but also fundamentally alters the hydration pathway of CAC. LS effectively mitigates the strength degradation commonly associated with phase conversion in conventional CAC systems by suppressing the formation of metastable phases (CAH10 and C2AH8) and directly promoting the formation of monocarboaluminate (Mc). At the optimal LS content of 10 wt%, chemical regulation via Mc formation and the physical effects caused by filling and nucleation act synergistically, leading to enhanced interlayer bonding and a dense microstructure. As a result, the printed sample displays a compressive strength of 10 MPa after 24 h, exceeding the 28 d strength of the control group. The compressive strength increases further to 18 MPa at 28 d, representing an 88.5% improvement compared to that of the control. This study provides a viable material design strategy for use in overcoming the inherent strength limitations of CAC in BJ3DP, and it offers a promising pathway for application in developing complex, high-performance cement-based 3D-printed components.

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