DAfStb directive: “Durability of concrete structures based on the exposure resistance class system” (ERC guideline)
The draft for enquiry of the DAfStb directive “Durability of concrete structures based on the exposure resistance class system (ERC guideline)” was recently completed by the DAfStb subcommittee “Durability of concrete structures,” and the draft for enquiry process is underway. The new ERC guideline can be used in the future as an alternative to the descriptive requirements of DIN 1045 for ensuring the durability of concrete structures.
The new EC2 contains so-called exposure resistance classes (ERC) for the damage mechanisms of carbonation and chloride-induced reinforcement corrosion. The concrete cover is then determined based on the ERC, the exposure class, and the service life (50 years and 100 years). In a first step, the DAfStb’s ERC guideline takes up the performance-based ERC concept of EC2 for exposure classes XC1 to XC4, XD1/XS1, and XF1 (approx. 80% of today’s concrete market) and expands this in line with national regulations (the complete new DIN 1045 series of standards, the BAW code of practice MDCC, etc.). In contrast to the regulations of the future EC2, the ERC guideline reduces the ERC resistance classes to a manageable, practice-relevant number and determines the thickness of the concrete cover not only on the basis of the ERC, exposure class, and service life, but also in accordance with the curing class according to DIN 1045-3:2023-08. In addition, the ERC guideline for classifying concrete into corresponding ERC classes defines limit values for performance tests in accordance with BAW code of practice MDCC, Annexes A and B. The durability to frost exposure (XF1) can be ensured by using the descriptive concept or a performance test in accordance with DIN CEN/TS 12390-9. By applying the ERC concept, sustainability requirements can also be implemented more easily by eliminating limit values (minimum cement content, maximum permissible w/c ratio) – for example, by designing concretes with very low clinker content.
