Production and Drying of Poured Earth Elements

There are two major challenges for Think Earth Subproject 3 "Production and Drying of Poured Earth Elements." On the one hand, the lack of knowledge about reliable material parameters and model concepts for the dimensioning of load-bearing, poured and prefabricated earth building walls in building structures. On the other hand, the efficient drying of these prefabricated poured earth building walls remains an outstanding issue. Pouring the earth into conventional formwork using admixtures has already been successfully tested. This approach reduces the amount of water required to make the earth mixture workable and increases the early strength of the material so that the formwork can be removed within 4-5 days. Thanks to this achievement, the entire existing infrastructure for concrete construction (mixers, truck mixers, formwork, equipment for compaction and surface treatment, etc.) can also be fully reused for prefabricated poured earth construction.

The key factor for the prefabrication of earth building walls is drying and the associated increase in the strength of the earth building wall elements. Time-consuming air drying is not economical, especially on a construction site. Initial tests with a vacuum drying process have been carried out successfully, although the process must be further optimized. The drying process is therefore being investigated in a work package in this subproject. The various drying methods are to be accompanied by a life cycle assessment. The economic target value of poured earth prefabrication is based on the values already established for concrete prefabrication, considering the likely increase in costs due to CO2 certificates. Further work packages include tests on force input and output as well as force transmission via the joints of the previously noted poured earth building walls.