Influence of CaCO[sub.3] on Density and Compressive Strength of Calcium Aluminate Cement-Based Cementitious Materials in Binder Jetting

• Published in: Materials 2024-07, Vol.17 (14)
• Main Authors: Kim, Tae-Hyung, Ye, Bora, Jeong, Bora, Lee, Myeung-Jin, Song, Aran, Cho, Inkyung, Lee, Heesoo, Kim, Hong-Dae
• Format: Article
• Language: English
• Subjects: 3D printing; Cement; Powders
• ISSN: 1996-1944; 1996-1944
• DOI: 10.3390/ma17143463

We investigated the impact of CaCO[sub.3] addition on the density and compressive strength of calcium aluminate cement (CAC)-based cementitious materials in binder jetting additive manufacturing (BJAM). To confirm the formation of a uniform powder bed, we examined the powder flowability and powder bed density for CaCO[sub.3] contents ranging from 0 to 20 wt.%. Specifically, powders with avalanche angles between 40.1–45.6° formed a uniform powder bed density with a standard deviation within 1%. Thus, a 3D printing specimen (green body) fabricated via BJAM exhibited dimensional accuracy of less than 1% across the entire plane. Additionally, we measured the hydration characteristics of CAC and the changes in compressive strength over 30 days with the addition of CaCO[sub.3]. The results indicate that the addition of CaCO[sub.3] to CAC-based cementitious materials forms multimodal powders that enhance the density of both the powder bed and the green body. Furthermore, CaCO[sub.3] promotes the formation of highly crystalline monocarbonate (C[sub.4]AcH[sub.11]) and stable hydrate (C[sub.3]AH[sub.6]), effectively inhibiting the conversion of CAC and showing compressive strengths of up to 5.2 MPa. These findings suggest a strong potential for expanding the use of BJAM across various applications, including complex casting molds, cores, catalyst supports, and functional architectural interiors.