Analyse der Durchflussraten in gerissenem Stahlbeton.

Translation abstract <bold>Analysis of Flow Rates in Cracked Reinforced Concrete</bold>Cracks in reinforced concrete structures are part of the construction principle and acceptable as long as they do not exceed certain limits. According to Eurocode 2, part 3, (as well as the guideline of the German Committee for Structural Concrete (DAfStb)) the autogenous healing of separation cracks with a width ≤ 0.20 mm can be considered under certain hydraulic conditions. However, practical experience shows that self‐healing does not always reliably occur even when this crack width is maintained. This study examines the flow rates of centrally cracked and water‐permeated concrete using Edvardsen's method. Based on the experimental results, an analytical approach following Hagen‐Poiseuille is developed to estimate the flow rate immediately after the start of the water flow, which is particularly relevant for tightness class TC0. This flow rate also serves as an indicator for evaluating the efficiency of autogenous self‐healing in structures of tightness class TC1. The initial flow rate <italic>Q</italic>0 through cracked concrete is mainly influenced by the crack width distribution across the cross‐section, the water pressure, the roughness of the crack flanks, and the tortuosity of the crack path. Therefore, a reliable estimation of the flow rate necessitates the introduction of a correction factor ξ, which is proposed with 0.52 due to the high variability of the experimental data. [ABSTRACT FROM AUTHOR]