Identifikation und Beurteilung der Alkali-Kieselsäurereaktion unter Einbeziehung österreichischer Schadensfälle

Translated title of the contribution: Identification and assessment of alkali-silica reaction with involvement of Austrian damage cases

Eva Katharina Fischböck

Research output: ThesisDoctoral Thesis

Abstract

Alkali-silica reaction (ASR) is a damage reaction occurring in concrete resulting from reactive aggregates, which is a worldwide problem regarding the durability of concrete. Up to now Austrian aggregates were considered as minor reactive. Therefore, ASR research has been less extensive in Austria than elsewhere, e.g. in Germany. Out of this reason the aim of this thesis was to develop an investigation procedure, which enables the best possible assessment of ASR damage initiated by Austrian aggregates. Therefore, published methods were applied and adapted according to the local damage characteristics. To do so, samples from two Austrian motorways were investigated. These results showed that non-destructive tests provide valuable information for the assessment of the damage. Thus, continuative work was done to test an impulse-excitation technique for its applicability to detect ASR damage. The tests showed that the technique is applicable for ASR damage detection. Especially the damping of the resonant frequencies (mostly torsion resonant frequency) proved to be a very sensitive parameter in a very early stage of the reaction when crack initiation occurs. After just a few experiment days the damping parameters react with large increases. The further crack growth leads to a decrease of resonant frequencies, Youngs and shear modulus but leaves the damping unaffected because of the completed crack initiation process. Furthermore it could be shown that damping values of damaged samples permit statements regarding the damage even if the properties of the undamaged sample are unknown. Besides mechanical testing damage rating indexes were determined from microscopic investigations. Comparison with mechanical parameters showed that because of differing damage characteristics of various aggregates an inference from microscopic to mechanical parameters of the concrete is not possible.
Translated title of the contributionIdentification and assessment of alkali-silica reaction with involvement of Austrian damage cases
Original languageGerman
QualificationDr.mont.
Supervisors/Advisors
  • Harmuth, Harald, Assessor A (internal)
  • Stark, Jochen, Assessor B (external), External person
Publication statusPublished - 2009

Bibliographical note

embargoed until null

Keywords

  • alkali-silica reaction concrete durability damage assessment non-destructive test method damping attenuation damage rating index

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