Additive materials

Additive materials are those which are used in additive fabrication methods, also known as 3D printing. Depending on the specific sub-process used, these may be ductile to allow extrusion, or have a powder configuration to allow for selective solidification. The below list features materials found to have been already experimented in stereotomic design, which explains missing possibilities like concrete.

• Clay – While traditionally modelled by hand, clay has been one of the most used materials in material extrusion for its ease of handling. When it is mixed with water, the clay powder becomes a paste which, after being extruded, dries over time. A myriad of explorations have researched on 3D printing clay bricks for walls or columns, while few researchers such as Peters (2012), Langenberg (2018) or Carvalho et al. (2018) have applied this technology in the pursuit of transversing spans through stereotomic techniques.
• Plastic – The rapid expansion of small scale 3D printers is based in Material Extrusion technology which largely uses plastic filament as printing material. Using a small 3D printer to produce small construction blocks that, after assembly, produce a large scale architectonic work has been explored by maker enthusiasts. The stereotomic idea of using specially geometrized blocks to overcome gravity is used to a successful extent in the Solar Bytes Pavillion arch (Peters, 2016) and more recently in a much larger scale four legged vault called VULCAN (Xu, 2016).
• Sand – The fine grained, powder like sand, is a very efficient material in the binder jetting additive process. Simultaneously, compacted sand is a highly performative material in compression. These properties are combined in the discrete 3D sand-printed floor prototypes (M. Rippmann et al., 2018) where stereotomic principles of parts within the whole allow for a large slab to be produced in a limited size printer.