Effect of the printing method and mortar's workability on pull-out strength of 3D printed elements

Abstract

3D Printing of Concrete is gaining more attention with time as an alternative method for construction for its high degree of freedom. Until now, most of 3D printed elements are pre-printed then moved to their designated locations. The most practical method for moving printed elements is lifting them by means of implemented anchors. However, due to the nature of this construction method, it does not allow for any type of vibration, also due to the use of a special type of concrete mix, that do not flow by itself, there are still a lot of queries concerning the adherence of concrete with steel bars. The objective of this paper is to characterize the bond between steel and printed mortars as a function of mortars workability and printing method. Pull-out tests of an 8 mm steel bar embedded in either printed or non-printed mortars of varying workability have been performed after 3 days of casting. It is found that the workability of the ink does not affect the pull-out strength, neither the printing method nor layers direction affect the pull-out strength in respect to the steel bar.