Concrete is one of the most important building materials of our time. However, the burning of the required cement causes 8 % of the global climate-damaging CO2 emissions. The use of natural microbiological processes to consolidate aggregate into so-called bioconcrete represents a promising and potentially CO2-neutral alternative to cement-bound concrete.
Certain bacteria possessing a urease enzyme are able to initiate the formation of calcium carbonate crystals when the necessary substances are provided. The process is known as microbiologically induced calcite precipitation (MICP). Bioconcrete is the name given to a building material in which aggregate is bound and consolidated by the calcium carbonate crystals formed.
Bioconcrete can already be used in some areas of construction, such as closing cracks in concrete, fixing sandy soils and making bricks. To date, however, there are no processes with which bioconcrete can be used to manufacture large-format load-bearing structural components. Yet reinforced concrete is by far the most widely used building material in Germany. The development of concepts for the production of reinforced load-bearing components from bioconcrete offers great potential for CO2 savings. At the ILEK, process principles are therefore being developed for the production of components made of bioconcrete, which are intended to expand its application in the construction industry.
In addition to suitable mix compositions and component geometries, the integration of basalt fibers for the production of purely mineral reinforced components made of bioconcrete is being investigated.
In cooperation with the Institute of Microbiology at the University of Stuttgart (IMB), a process for the additive manufacturing of porous components has already been developed that enables homogeneous cementation.
In the ongoing research project "Biobeton - Fundamentals and process principles for the production of CO2-neutral and resource-efficient components", the ILEK is investigating further approaches to component production together with the IMB and the Institute for Control Engineering of Machine Tools and Manufacturing Facilities at the University of Stuttgart.