On 16 July 2026, our SFB 1313 team offered for the second time a porous media school workshop on biomineralization to a group of nine curious 11th grade pupils from the Karls Gymnasium Stuttgart.
Producing concrete using conventional methods emits massive amounts of CO2. At the University of Stuttgart, and especially within SFB 1313 (research project C04), researchers work on an alternative way. The microbial processes of biomineralization can be used to produce environmentally friendly bio-concrete. The living organisms produce inorganic material through chemical reactions.
A powder containing bacteria is mixed with sand. The mixture is placed into a mold and flushed with a solution containing calcium and urea over the course of four days in an automated process. The breakdown of urea by the bacteria and the presence of calcium ions, causes crystals of calcium carbonate to grow. This solidifies the sand mixture into bio-concrete. At the end of the process, a solid is produced that is chemically similar to natural calcareous sandstone. This product can be produced from waste materials – such as urine – and has a significantly lower ecological footprint.
SFB 1313 spokesperson Holger Steeb welcomed the class and our doctoral researchers Lara Reichart and Christoph Nething gave an introduction into the topic.
Experimenting with porous media
After gaining background knowledge on biomineralization, the pupils could experiment themselves at the Porous Media Lab (PML). Christoph Nething and his team prepared solid sand samples, with which the group could conduct the following mechanical experiments, set-up by Hamid Reza Madadi Varzaneh, that are important to characterize the materials.
- Micro XRCT scan: this experiment serves to watch inside a sample.
- Fatigue test: to evaluate the behavior of material and components under recurring, cyclic loading
- Ultrasonic experiment: ultrasonic techniques (high-frequency sound waves) are utilized for non-destructive testing (NDT) and material characterization
Following the experiments, the group had the chance to breathe campus air. They enjoyed lunch together with our SFB 1313 team in the mensa of the University of Stuttgart, giving them time to discuss their results and experiences.
The event sparked enthusiasm and curiosity among the pupils, showing how porous media research at the University of Stuttgart can be both fun and impactful.
After lunch, the group got a tour to the Institute for Lightweight Structures and Conceptual Design (ILEK) and got to see the building, designed by the architect and former chair of the institute Frei Otto. They also had the chance to see the laboratory where the biomineralized samples are produced. At the end of the workshop, they also had the chance to see the "demonstrator building (D1244)".
Many thanks go to Lara Reichart, Christoph Nething and Hamid Reza Madadi Varzaneh for preparing and realising this great and fun workshop and to Samaneh Vahid Dastjerdi for the whole organisation.
