ABOUT THE INTERNATIONAL CONCRETE ABSTRACTS PORTAL

  • The International Concrete Abstracts Portal is an ACI led collaboration with leading technical organizations from within the international concrete industry and offers the most comprehensive collection of published concrete abstracts.

International Concrete Abstracts Portal

  


Title: Microstructural Packing, Rheology, and Ram Extrusion Characteristics of 3-D-Printable Cementitious Binders

Author(s): Sooraj Nair, Aashay Arora, Hussam Alghamdi, Narayanan Neithalath

Publication: Web Session

Volume:

Issue:

Appears on pages(s):

Keywords:

DOI:

Date: 10/15/2018

Abstract:
Cementitious binders amenable to extrusion and layered 3D printing are formulated by ensuring appropriate particle size distributions using fine limestone powder or a combination of limestone powder and microsilica or metakaolin. Mixtures were proportioned with and without a superplasticizer to enable different particle packings at similar printability levels. A microstructural packing coefficient, based on simulated fresh paste microstructure is defined, which is well-related to rotational and extensional rheological parameters of the pastes. This parameter is shown to be useful in selecting preliminary material combinations for layer-wise printable pastes. Extrusion rheology experiments, where the ram extruder is moved at different velocities and the corresponding extrusion force recorded, are used in conjunction with a phenomenological model to better understand extrusion printing of cementitious materials. The extensional yield stress and die wall slip shear stress extracted from the model, critical in extrusion-based 3D printing, show good correlation with microstructural packing.