Project 5: Acceptance tests on the construction site / Acceptance tests on the structure

Project duration: May 2021 to April 2023

The durability of concrete structures is currently ensured descriptively in the relevant codes, among other things by limit values for the concrete composition (maximum permissible w/c ratio, minimum cement content) and the minimum concrete cover. According to the current state of the regulations, the corresponding verification for the concrete is carried out indirectly on the basis of its compressive strength, in addition to checking the limit values for the composition. In the future, the durability of concrete structures is to be ensured according to a performance-oriented concept. For this purpose, so-called "Exposure Resistance Classes" (ERC) will be introduced in the relevant European standards, which define clear evaluation criteria for certain durability-relevant properties (including resistance to carbonation, chloride penetration, and freeze-thaw/freeze-thaw salt). However, the direct performance testing procedures coupled with these are costly and time-consuming, so that as a stand-alone tool they do not provide the scope for adequate
monitoring of the durability-relevant properties in practice. In order to be able to evaluate the latter reliably and precisely on the construction site, indirect and more easily manageable test methods should therefore be included.

The aim of this research project is, based on correlation analyses between direct and indirect test methods (e.g. chloride migration coefficient electrolyte resistance), to define corresponding performance-oriented acceptance criteria on the construction site / acceptance criteria on the structure in order to verify the durability of the concrete over the intended service life of the structure. The investigations envisaged here are intended to support the changeover to a genuine performance principle in practice. This facilitates the transition to the new concept for the companies concerned (e.g. construction companies, testing laboratories), especially SMEs, which can also be reflected positively in economic terms.

Key publications