Determination of the characteristic concrete compressive strength of existing structures according to DIN EN 13791:2020 for small sample sizes - Evaluation and comparison with valid existing approaches

The assessment of existing structures is becoming increasingly important, because in the sense of resource-efficient handling of existing buildings, conversion should be given priority over demolition and new construction. Until now, the characteristic concrete compressive strength of existing structures in Germany has been calculated according to DIN EN 13791/A20:2017. DIN EN 13791:2020, which was introduced in February 2020, will replace DIN EN 13791:2008, which was previously valid in Europe, and DIN EN 13791/A20:2017, which was valid in Germany. Especially for small sample sizes of drill cores (3 <= n <= 7), the introduction of DIN EN 13791:2020 results in significant changes in the determination of the characteristic in-situ concrete compressive strength. However, there is currently no background information available on the statistical robustness of the new methods, which is why this is to be checked within the framework of the research project DBV 317.