Designing 3D printable cementitious materials with gel-forming polymers

Published

December 11, 2020

Author(s)

Edward Garboczi, Hajar Taheri Afarani, William carroll, Joseph J. Biernacki

Abstract

Cement based pastes for 3D printing applications were prepared using hydrogel-forming polymers. Preliminary results suggest that such gel-forming polymers can reduce the need for more complex admixture packages as printing aids. The influence of polymer content and gel/cement ratio on paste printability was investigated. Three printability metrics were developed to assess deviations from target objectives. Regression analysis were performed to obtain the most influential mix formulation effects. Printability windows were established for each gel that indicate clear differences in gel performance. An inverse relationship between gel and paste rheology and printability was found. While a mechanically stiff gel is preferred, for stability of the 3D printed object before curing, a more flowable (less stiff) gel was found to result in more printable cement pastes. Thermoporometry and diffusion-ordered nuclear magnetic resonance (DOSY-NMR) spectroscopy were used to explore why some gel-forming polymers provide broader domains of printability than others based on hydrogel pore structure and nature of the entrapped water. The obtained results, including the printability indexes (PI), the most influential mix formulation factors, and rheological measurements, form a framework for selection of gel-based printing aids and can be used as a basis for quality control of 3D printed objects and optimization of printability.

Citation

Construction and Building Materials

Volume

268

Pub Type

Journals

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DOI Link

Keywords

3D printing, cement-based materials, hydrogels, rheology, storage and loss moduli, printability index

Citation

Garboczi, E. , Afarani, H. , Carroll, W. and Biernacki, J. (2020), Designing 3D printable cementitious materials with gel-forming polymers, Construction and Building Materials, [online], https://doi.org/10.1016/j.conbuildmat.2020.121709 (Accessed October 31, 2024)