Effect of different silica particles on flowability of gypsum powder for 3D powder printing

• Published in: Construction & building materials 2019-08, Vol.217, p.394-402
• Main Authors: Ma, Baoguo, Jiang, Qi, Huang, Jian, Wang, Xin, Leng, Jinyue
• Format: Article
• Language: English
• Subjects: 3D powder printing; Flowability; Gypsum powder; Silica
• ISSN: 0950-0618; 1879-0526
• DOI: 10.1016/j.conbuildmat.2019.05.097

•Silica of different types was used to treat the surface of gypsum particles.•Hydrophobic nanosilica effectively enhanced the flowability of gypsum powder.•The quality of gypsum-based products was improved in the field of 3DPP. 3D powder printing (3DPP) attracts much attention in the field of construction and decoration. However, the strong hygroscopicity and high tendency to agglomerate of gypsum powder give rise to a poor flowability, which is crucial during large-size 3DPP procedure. This study aims to compare gliding effect of silica particles with different sizes, shapes and surface properties on poor-flow gypsum powder. Angle of repose (AOR), flow rate of the modified powders and surface morphology of the modified particles were evaluated. The results showed that silica particles of different hydrophobicity presented various extent of glidant effect. For hydrophobic nanosilica, an optimum content (1.0 wt% in this study) could best minimize AOR of the modified powder, leading to more smooth and voidless powder bed of gypsum powder than unmodified gypsum powder. The research found an optimum glidant which could improve the flowability of gypsum powder, resulting in good quality during 3DPP procedure.