TY - JOUR A1 - Breit, W. A1 - Dauberschmidt, C. A1 - Gehlen, C. A1 - Sodeikat, C. A1 - Taffe, Alexander A1 - Wiens, U. T1 - Zum Ansatz eines kritischen Chloridgehaltes bei Stahlbetonbauwerken N2 - Der Chloridgehalt, ab dem bei der Bewehrung im Beton mit Korrosion gerechnet werden muss, wird als kritischer Chloridgehalt bezeichnet. Die Höhe dieses kritischen Chloridgehaltes bestimmt in hohem Maße den Instandsetzungsumfang und damit die Instandsetzungskosten. Zahlreiche Labor- und Bauwerksuntersuchungen belegen, dass dieser kritische Chloridgehalt von einer Vielzahl von Parametern abhängt und deswegen kein fester Wert sein kann. Aus diesem Grund ist es sinnvoll, über Betrachtung von Korrosions- bzw. Depassivierungswahrscheinlichkeiten einen unteren kritischen Chloridgehalt zu bestimmen, bei dem bei gegebenen Randbedingungen nur mit einer geringen Wahrscheinlichkeit (z. B. 5%-Fraktilwert) Korrosion von Stahl in Beton zu erwarten ist. Die Auswertung von zahlreichen Untersuchungen zeigt, dass der Ansatz eines kritischen Chloridgehaltes von 0, 5 M.-% bezogen auf den Zementgehalt bei Einhaltung bestimmter Randbedingungen mit einer hinreichend geringen Korrosionswahrscheinlichkeit korreliert und somit auch in Übereinstimmung mit der Richtlinie 'Schutz und Instandsetzung von Betonbauteilen' des DAfStb als unterer kritischer Chloridgehalt unter Praxisbedingungen anzusetzen ist. KW - Dauerhaftigkeit KW - Instandsetzung KW - Korrosion KW - Lebensdauer KW - Parkhäuser KW - Tiefgaragen KW - Betontechnologie KW - LIBS KW - Alkalität KW - Bewehrungsoberfläche KW - Bohrkernproben KW - Bohrmehl KW - Chloridgehalt KW - Chloridinduzierte Korrosion KW - Chloridprofile KW - Dauerhaftigkeitsbemessungen KW - Depassivierung KW - Depassivierungswahrscheinlichkeiten KW - Lochfraßkorrosion KW - Monitoring KW - Passivität KW - Potentialfeldmessungen KW - Probenentnahme KW - Richtlinie für Schutz und Instandsetzung KW - RL-SIB;Schädigungen KW - Baustoffe KW - Bauwerkserhaltung/Sanierung KW - Bauwerksüberwachung KW - Bewehrung PY - 2011 U6 - https://doi.org/10.1002/best.201100007 SN - 0005-9900 SN - 1437-1006 VL - 106 IS - 5 SP - 290 EP - 298 PB - Ernst CY - Berlin AN - OPUS4-23758 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Gebauer, D. A1 - Gutiérrez, R, A1 - Marx, S. A1 - Butler, M. A1 - Grahl, K. A1 - Thiel, T. A1 - Maack, Stefan A1 - Küttenbaum, Stefan A1 - Pirskawetz, Stephan A1 - Breit, W. A1 - Schickert, M. A1 - Krüger, M. T1 - Interrelated dataset of rebound numbers, ultrasonic pulse velocities and compressive strengths of drilled concrete cores from an existing structure and new fabricated concrete cubes N2 - Two test series were examined using nondestructive measuring methods by six independent laboratories before determining their compressive strength. The nondestructive test methods used were the rebound hammer and ultrasonic pulse velocity measurement. Two types of geometries were investigated: drilled cores and cubes. The measurement procedure for each of these datasets is conditioned to the geometry and is therefore different. The first series consists of 20 drilled cores (approximately diameter/height = 10 cm/20 cm) from the 55-year-old Lahntal Viaduct near Limburg, Germany. After preparation in the first laboratory, the lateral surface of the drilled cores was tested with the rebound hammer using a given pattern. Every laboratory tested every drilled core at different locations. Ultrasonic measurements in transmission were performed repeatedly at predefined points on the flat surfaces of the specimen. The second series consisted of 25 newly manufactured concrete cubes of a mix with a target concrete strength class of C30/37. The edge length was 15 cm. Each laboratory received five specimens of this test series. Thus, contrary to the first series, each specimen was tested by only one laboratory. Two side faces of each cube were tested with the rebound hammer. In addition, ultrasonic measurements were performed by one laboratory. The time of flight was measured between the tested side faces of the rebound hammer at different positions. For both series, rebound hammers were used to determine the R-value as well as the Q-value. The rebound hammer models within the laboratories were always the same, while they differed between the laboratories. The ultrasonic measurements took place with different measurement systems and couplants. Finally, both specimen series were tested destructively for compressive strength. The dataset contains the raw data summarized in tabular form. In addition, relevant calculated data are included in some cases. For the ultrasonic measurements, the time of flight has already been converted into the ultrasonic velocity. Besides, in addition to the raw data of the compressive strength test (force, weight, and geometry values), the calculated compressive strengths and densities are also provided. KW - Nondestructive testing KW - Ultra sound KW - Rebound hammer KW - Existing structure KW - Civil engineering PY - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:b43-574655 SN - 2352-3409 VL - 48 IS - 109201 SP - 1 EP - 13 PB - Elsevier Inc. AN - OPUS4-57465 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -