Title: Print Geometry Alterations and Layer Staggering to Enhance Mechanical Properties of Plain and Fiber- Reinforced Three-Dimensional-Printed Concrete

Author(s): Avinaya Tripathi, Sooraj A. O. Nair, Harshitsinh Chauhan, and Narayanan Neithalath

Publication: Materials Journal

Volume: 121

Issue: 2

Appears on pages(s): 17-30

Keywords: anisotropy; compressive strength; flexural strength; layer geometry; three-dimensional (3-D) concrete printing

DOI: 10.14359/51740262

Date: 4/1/2024

Abstract:
Conventional approaches to concrete three-dimensional (3-D) printing relies on printing concrete in a straight (linear) print path, with layers overlaid on top of each other. This results in interlayer and interfilament joints being potential weak spots that compromise the mechanical performance. This paper evaluates simple alterations to the print geometry to mitigate some of these effects. A printable mixture with 30% of limestone powder replacing cement (by mass), with a 28-day compressive strength of approximately 70 MPa in the strongest direction is used. S- and 3-shaped print paths are evaluated as alternatives to the linear print path. Staggering of the layers ensures that the interfilament joints do not lie on the same plane along the depth. Flexural strength enhancement is observed when print geometries are changed and/or layers are staggered. The study shows that print geometry modifications mitigate mechanical property reductions attributed to interfilament defects in 3-D concrete printing.