3D printing of concrete : the influence on chloride penetration

3D concrete printing is one type of additive manufacturing (AM) which comprises all modern techniques of fabricating building elements layer by layer. It shows great perspectives with respect to freedom of form, time management and eco-friendly use of the material as the material is only applied where it is necessary. However, due to the lack of formwork and the layered end result, this construction technique induces more shrinkage, internal voids and crack formation, increasing the amount of preferential ingress paths for chemical substances. The additional amount of voids caused by this layered fabrication technique will not only induce anisotropic properties on a structural level, but will also affect the microstructure and durability of the printed specimens. For the aim of this research, 3 different time gaps are selected to investigate the influence of the layered construction process on chloride penetration and a comparison with traditional cast concrete was made. First results showed that the print process affects the chloride penetration in a significant way. Although the ingress front is uniform in both cases, the chloride ingress is approximately three times higher in case of specimens fabricated with a zero minute time gap compared with traditional cast elements and this only after one week of chloride exposure. An increased time gap increases the porosity at the interface and consequently also the chloride ingress rate of the printed elements.

ISBN:9783030499167

Publication year:2020

Accessibility:Closed