New Potentials of Biocement
Biocement - a sandstone which is produced with the aid of bacteria, urea and calcium. In comparison to other mineral materials, it is the microbial production that makes Biocement unique. Every local type of sand can be used for the process. In contrast to fired materials it saves a lot of energy, since hardening takes place at low temperature while applying light pressure. The additive way of manufacturing enables new possibilities in shaping natural stone.
On a creative, scientific and technical basis New Potentials Of Biocement shows sustainable and future-oriented approaches in designing with microbial produced sandstone.
Is it possible to use the determined material mix in 3D printing technologies?
Considering recent developments in materials research as well as the vision of realizing any appropriate shape, we intended to push the possibilities of additive manufactured Biocement. Therefore, we made a multitude of material experiments: We transformed the ingredients into a paste-like material (Liquid Deposition Modelling), we alternately layered the sand and the liquid substances (Binder Jetting) and finally came up with a special kind of 3D printed formwork.
How could a Biocement-producing machine look like?
After figuring out our way of producing Biocement, we set up the necessary equipment. First, bacteria Sporosarcina Pasteurii is cultivated in a small container of nutrient medium. Afterwards, the bacterial solution is mixed with sand and poured in a perforated mould. The filled formwork is placed in a large tank of cementation solution, containing urea and calcium. Additionally, this second solution gets pumped through the mould. Here it causes the production of calcium carbonate which finally binds the grains of sand together. After pumping fresh solution through the formwork for several days, the sand is transformed to Biocement and can be removed from the mould. The tiny holes all over the formwork ensure a homogeneous cementation process which allows us to realize complex geometric shapes.
What kind of objects are suitable for this mineral material?
We have taken a look at the characteristics of Biocement itself and got fascinated by its hygroscopic abilities. We applied the naturally cooling effect on three-dimensional tiles. Due to an integrated, refillable reservoir a wall of tiles is improving the indoor climate.
Julia Huhnholz, Friedrich Gerlach
Uli Budde, Jun.-Prof. Dr. Jan Willmann, M.A. Michael Braun