Whether it´s the Porta Nigra, castles from the medieval times or the ancient wall in the parallel street: the natural look adds a certain charm to buildings.
Especially old buildings from the time of the Romans, but also from more recent times are built of natural stone. Very popular are the sandstones from the Rotliegendes or the Buntsandstein, material that is already over 200 million years old. Compared to granite or basalt, sandstones have the advantage of being relatively easy to work with. However, this is also associated with a major disadvantage: They are not very resistant to weathering. In the context of monument preservation, but also in the renovation of buildings, parts or even entire sculptures have to be replaced frequently.
But where will the replacement come from if the quarry is no longer in operation or the rock deposit is completely exhausted? Waiting for a new deposit is unthinkable.
In the project “3D-Geo” funded by the German Federal Ministry for Economic Affairs and Energy as part of the Zentrales Innovtionsprogramm Mittelstand (short: ZIM, innovation programme for small to medium sized enterprises), we at WZR ceramic solutions worked on this problem together with Opus Denkmalpflege GmbH (Berlin) and the Chair of Construction Chemistry and Polymer Materials at Bauhaus University Weimar precisely – and now we held the final result in our hands!
A 3D-printed, synthetically produced sandstone that has the necessary properties for use as a natural stone substitute without thermal post-treatment. After processing, who would still suspect that it is initially a component produced by means of material extrusion?
The result of the ZIM project therefore answers the initial question quite well: No, ceramics can also be produced without sintering.
Moreover, solidification by geopolymers comes with a significantly lower environmental impact than the production of ceramics or cement. For this reason, we at WZR are already continuing to work on the topic of “cold solidifying” ceramics. At Ceramitec 2022, we were able to present a first cold-produced brick.
For more information about the project 3D-Geo visit our previous blog post: https://wzr.cc/3-d-druck-von-naturstein-fuer-die-denkmalpflege/