Hydroabrasionsbeanspruchung von Verkehrswasserbauwerken

Abstract

Im Bereich des Verkehrswasserbaus werden Betonoberflächen durch Hydroabrasion in unterschiedlicher Intensität beansprucht (z. B. Tosbecken, Wehrrücken). Eine Beschreibung der Einwirkung bei und des Betonwiderstandes gegenüber Hydroabrasion ist im derzeitigen Regelwerk der EN 206‐1 bzw. EN 206 nicht und im nationalen Anwendungsdokument zur EN 206‐1, der DIN 1045‐2, nur ansatzweise enthalten. Das wasserbauspezifische Regelwerk der ZTV‐W LB 215 für den Neubau bzw. LB 219 für die Instandsetzung greift derzeit im Wesentlichen auf die Regelungen der DIN 1045‐2 zu den XM‐Klassen zurück. Bei der Bundesanstalt für Wasserbau (BAW) in Karlsruhe wird im Rahmen eines Forschungsvorhabens in Zusammenarbeit mit Forschungseinrichtungen das Ziel verfolgt, diese Regelungen für Betonausgangsstoffe, Betonzusammensetzungen und Betoneigenschaften zur Sicherstellung eines hinreichenden Widerstandes gegenüber Hydroabrasion zu verifizieren. Bestandteil dessen ist die Erarbeitung einer Klassifizierung analog zur Expositionsklassensystematik der DIN 1045‐2 für die Hydroabrasionsbeanspruchung. Der vorliegende Beitrag stellt die aktuellen Aktivitäten zur Beschreibung der Einwirkung durch Hydroabrasion dar. Hydroabrasive exposure of hydraulic structures In the field of waterways engineering concrete surfaces are exposed to hydroabrasion in different intensity (e. g. stilling basin, weir body). A description of the exposure to and the concrete's resistance against hydroabrasion is not included in the current European standard EN 206‐1 respectively EN 206. In the German National Application Document (DIN 1045‐2) used with EN 206‐1 it is only considered rudimentarily. The specific regulations for hydraulic engineering regarding construction (ZTV‐W LB 215) and repair (ZTV‐W LB 219) refer to the regulations of DIN 1045‐2 for exposure of concrete to wear (XM). A research project of the Federal Waterways Engineering and Research Institute in Karlsruhe, in collaboration with different research institutes, pursuits to verify these regulations for concrete constituent materials, concrete mix design and concrete properties to assure a sufficient resistance of the concrete against hydroabrasion. The formulation of a classification in line with the system of exposure classes for concrete exposed to wear according to DIN 1045‐2 is an integral part of this project. The following contribution presents the current activities to characterise the exposure to hydroabrasion.

Field Investigation on Hydroabrasion in High-Speed Sediment-Laden Flows at Sediment Bypass Tunnels

“…The field study of [94] was conducted in a weir stilling basin, presumably retaining sediments in a recirculating flow field. As a result, the same sediments repeatedly impacted the invert [95], resulting in a bias of k v towards lower values. Omitting the k v -values of [36,94] due to different properties of invert materials and the non-representative test set-up, respectively, significantly reduces the data scatter.…”

Hydroabrasive Exposure and Concrete Resistance against Abrasion Erosion

“…The evaluation revealed erosion depths up to several dm [8 to 25 in.]. About 50 % of the weirs and 30 % of the locks reveal abrasion erosion damages of different degree [3]. During the structural inspection according to the BAW Code of Practice "Classifying Waterway Construction Damages" [4] the damage is rated on a scale from 1 -4 (1: good condition, 4: critical condition).…”

“…To gather information for these buildings investigations were conducted by the Technical University of Dresden by order of the Federal Waterways Engineering and Research Institute [15]. A Summary of the results was presented in [3]. The flow velocities of four weirs were determined by 3D-hydronumerical-suimulations with typical ranges of flow velocities on the weir sills up to 3.5 m/s (12 ft/s).…”