Detection of alkali-silica reaction by means of ultrasonic sounding - a pilot study

0444509 - GLÚ 2016 RIV CA eng C - Konferenční příspěvek (zahraniční konf.)
Lokajíček, Tomáš - Petružálek, Matěj - Svitek, Tomáš - Šťastná, A. - Šachlová, Š.
Detection of alkali-silica reaction by means of ultrasonic sounding - a pilot study.
Innovations in Applied and Theoretical Rock Mechanics. Montréal: Canadian Institute of Mining, Metallurgy and Petroleum, 2015. ISBN 978-1-926872-25-4.
[International Congress of Rock Mechanics /13./. Montréal (CA), 10.05.2015-13.05.2015]
Grant CEP: GA ČR(CZ) GAP104/12/0915
Institucionální podpora: RVO:67985831
Klíčová slova: Mortar bar test * ASR * aggregates * ultrasonic sounding * time domain analysis * longitudinal wave velocity * frequency domain analysis
Kód oboru RIV: DC - Seismologie, vulkanologie a struktura Země

During the past 20 years, alkali silicate reaction (ASR) as a cause of concrete deterioration has been studied by a wide range of experimental methods such as microstructural and macrostructural analysis, bulk chemical analysis, X-ray and neutron diffraction analysis, etc. All of these data are compared with expansion values of mortar bars (following ASTM standard C 1260). Ultrasonic testing methods (including ultrasonic pulse velocity UPV) are widely used to determine material mechanical properties and the changes induced by a variety of mechanical or chemical processes. However, only a few laboratory studies of ASR focused on ultrasonic testing of mortar bars. Due to this fact, a heating chamber was designed and constructed to enable ultrasonic sounding of mortar bar specimens while stored in accelerating solution. Regular ultrasonic sounding of mortar bars reveals significant dependence of ultrasonic data such as longitudinal P-wave velocity, signal energy, signal amplitude and signal frequency on mortar bar storage time. Ultrasonic data were subjected to time domain as well as frequency domain analysis. Different storage conditions were used to determine the effect of ASR on ultrasonic parameters. Mortar bars, prepared in the same manner with one type of aggregate, were stored in cold or warm water or in an accelerating warm medium. Ultrasonic data accurately reflects the differences in hardening and deterioration of tested mortar bars due to different storage conditions. Ultrasonic results showed very good correlation with the results of ASTM standard expansion tests and much higher sensitivity to ASR-induced concrete deterioration. Expansion tests showed 1% measured length differences in comparison with up to 80% resolution of ultrasonic data. The ultrasonic testing proved to be a suitable laboratory method for investigating ASR-related processes and could lead to an improvement of standard testing procedures.
Trvalý link: http://hdl.handle.net/11104/0247027