Publications / 2017 Proceedings of the 34rd ISARC, Taipei, Taiwan

Effect of Delay Time on the Mechanical Properties of Extrusion-Based 3D Printed Concrete

Taylor Marchment, Ming Xia, Elise Dodd, Jay Sanjayan and Behzad Nematollahi
Pages 240-245 (2017 Proceedings of the 34rd ISARC, Taipei, Taiwan, ISBN 978-80-263-1371-7, ISSN 2413-5844)

Extrusion-based 3D printing method is one of the main additive manufacturing techniques used in the construction industry which is capable of producing large-scale building components with complex geometries. The mechanical properties of the printed concrete component is very much unlike the conventionally cast concrete. Therefore, the properties of these are important for the design of structures built with these printing process. In this study, an apparatus was built to simulate extrusion-based 3D printing process. Layered structures with 10, 20 and 30-minute delay time have been printed using ordinary Portland cement (OPC). Mechanical properties including compressive, tensile and interlayer bonding strengths have been tested and the effect of delay time between each printing layers has been investigated. In both compressive and tensile strengths result, a bell curve pattern emerged. The 20-minute layered structures yield the highest result of 14.8 MPa (compressive) and 5.3 MPa (tensile), respectively. A significant inverse bell curve pattern emerged in the interlayer bonding strength. The 10 and 30-minute structures showed similar results, while the 20-minute structures had lower interlayer bonding strength noticeably. The paper presents an analysis of the results obtained. The major finding is that the bleeding of concrete plays a major role in the interlayer strength while the rate of setting is also important.

Keywords: Concrete, Additive Manufacturing, 3D Printing, Mechanical Properties