Title: Characterization of Extrudability Using Rheology and Desorptivity

Author(s): Kavya Vallurupalli, Nicolas Ali Libre, and Kamal H. Khayat

Publication: Materials Journal

Volume: 121

Issue: 2

Appears on pages(s): 5-16

Keywords: extrudability; fluid filtration; printability window; rheology; three-dimensional (3-D) printing

DOI: 10.14359/51740301

Date: 4/1/2024

Abstract:
Successful implementation of extrusion-based three-dimensional (3-D) printing requires the development of print materials with adapted rheology. In this study, filtration characteristics coupled with rheological properties of mortar mixtures are investigated to characterize the extrudability of print materials and establish a “printability window” (that is, the acceptable range of material properties for successful extrusion and shape stability). The extrudability was measured as the maximum force needed for the ram extrusion of the material. The fluid filtration rate was assessed in terms of desorptivity of the fresh mixture under pressure. The yield stress, plastic viscosity, and desorptivity were varied by changing the water-cement ratio (w/c), high-range water-reducing admixture (HRWRA) dosage, and welan gum (WG) content. Regression analysis indicated that during extrusion-based printing, the yield stress and desorptivity values can exhibit a more significant effect on extrudability than plastic viscosity.