immobilisation science laboratory, department of engineering materials, university of sheffield...
TRANSCRIPT
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Immobilisation Science Laboratory, Department of Engineering Materials, University of SheffieldAcoustic Emission Testing and Analysis Applied for Materials Used for Immobilisation of Nuclear WastesL.M. Spasova, M.I. Ojovan and F.G.F. Gibb
IAEA CRP on Cementitious Materials. Bucharest 24-28.11.2008
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OutlineAE project at the ISLExperimental SetupAE signature of corrosion of Al encapsulated in cementitious structuresPlans to complete the studyAE signature of partial melting and solidification/recrystallisation of natural granite
IAEA CRP on Cementitious Materials. Bucharest 24-28.11.2008
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At the BeginningObjective of the Project
FEASIBILITY of AE method to be applied to materials used for immobilisation of nuclear wastesV. Belov and A. Aloy, Using AE in quality control of glass and ceramics for radioactive waste immobilization, Mat. Res. Soc. Symp. Proc., 807, (2004), 163-168Courtesy of Prof Fergus Gibb180 days, 20 C and 95% RH AE project at the ISL
IAEA CRP on Cementitious Materials. Bucharest 24-28.11.2008
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Non-destructive Testing and Evaluation
IAEA CRP on Cementitious Materials. Bucharest 24-28.11.2008
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CountsAcoustic Emission
IAEA CRP on Cementitious Materials. Bucharest 24-28.11.2008
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Experimental Setup
IAEA CRP on Cementitious Materials. Bucharest 24-28.11.2008
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Corrosion of Al in CementsObservationHydrogen Gas Release7:3 BFS/OPC + Al7 daysRadial Cracks Formation and ExtensionSources of AE signals
IAEA CRP on Cementitious Materials. Bucharest 24-28.11.2008
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AE MonitoringNumber of AE SignalsBFS/OPC +Al (After mixing)BFS/OPC + Al (180 days)OPC + Al (90 days)OPC + Al (After mixing)
IAEA CRP on Cementitious Materials. Bucharest 24-28.11.2008
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AE Signal CharacteristicsAmplitudeOPC + Al (After mixing)BFS/OPC +Al (After mixing)OPC + Al (90 days)BFS/OPC + Al (180 days)
IAEA CRP on Cementitious Materials. Bucharest 24-28.11.2008
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AE Signal CharacteristicsPrimary FrequencyOPC + Al (After mixing)BFS/OPC +Al (After mixing)OPC + Al (90 days)BFS/OPC + Al (180 days)
IAEA CRP on Cementitious Materials. Bucharest 24-28.11.2008
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Signal ProcessingCross-correlation
Wavelet Transformation
where m= 1,2...2N-1 and N is the number of samples where is the centre frequency is a constant calculated as Suzuki, H., Kinjo, T., Hayashi, Y., Takemoto, M. & Ono, K., Appendix by Hayashi, Y., Wavelet Transform of Acoustic Emission Signals, J. Acoustic Emission, 1996, 14(2), 6984.
IAEA CRP on Cementitious Materials. Bucharest 24-28.11.2008
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BFS/OPC + Al (180 days)
IAEA CRP on Cementitious Materials. Bucharest 24-28.11.2008
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BFS/OPC + Al (180 days)Wavelet Transformation
IAEA CRP on Cementitious Materials. Bucharest 24-28.11.2008
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OPC + Al (90 days)
IAEA CRP on Cementitious Materials. Bucharest 24-28.11.2008
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Crack Initiation and PropagationC. Grosse, H. Reinhardt and F. Finck, J. Mater. Civil Engineering, 2003, 15 (3), 274-279 F. A. K. M. Uddin, M. Shigeishi and M. Ohtsu, Meccanica, 2006, 41, 425-442 Avnon and D. Yankelevsky, Engineering Fracture Mechanics, 1992, 42(6), 1041-1045 Crack propagation velocity 60 -200 m/sCrack propagation velocity : Plastic deformation stress wave velocity = 1:2 to 1:3Plastic deformation stress wave velocity = 20% of elastic wave velocityShear elastic wave velocity in concrete 2600 2800 m/sPlastic deformation wave velocity 520 560 m/sCrack propagation velocity ~173 186.6 m/sF. A. K. M. Uddin, K. Numata, J. Shimasaki, M. Shigeishi and M. Ohtsu, Constr. Build. Mater., 2004, 18, 181-188
IAEA CRP on Cementitious Materials. Bucharest 24-28.11.2008
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Cracks in Cementitious SamplesWavelengthOPC + Al (90 days)OPC + Al (4 years)
IAEA CRP on Cementitious Materials. Bucharest 24-28.11.2008
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Additional Experiments
Compression and tensile test of the cementitious samples Background Noise Cementitious samples (OPC and 7:3 BFS/OPC) with encapsulated Mg
IAEA CRP on Cementitious Materials. Bucharest 24-28.11.2008
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Melting and Solidification/Recrystallisation of GraniteCrystalCrystalGlassBeforeAfterGranite PowderSolid Granite
IAEA CRP on Cementitious Materials. Bucharest 24-28.11.2008
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Experimental SetupFurnacePressure Vessel
IAEA CRP on Cementitious Materials. Bucharest 24-28.11.2008
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AE MonitoringMelting of Granite SamplesConstant temperature (at 780 C) heating of granite powder sampleHeating of the solid granite sample
IAEA CRP on Cementitious Materials. Bucharest 24-28.11.2008
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AE signal CharacteristicsGranite PowderSolid GraniteExperiment with a solid quartz sample to be completed
IAEA CRP on Cementitious Materials. Bucharest 24-28.11.2008
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ConclusionsAcknowledgementsNational Nuclear Laboratory (BNFL, Nexia Solutions) and EPSRC for fundingAE technique is feasible to continuously monitor the performance of cement-based materials encapsulating metallic wastes such as aluminium.
IAEA CRP on Cementitious Materials. Bucharest 24-28.11.2008
100 1000 kHz is the operation range of the WD (wideband) type PAC (Physical Acoustics Corp.) AE transducer with 15 mm diameter. The resonance for the wideband sensor is at 125 KHz and for the R15D PAC type sensor is at 150 KHz. The R15D is used for detection of AE signals only from the pure OPC sample. The transducers were mounted on the outer surface of the bottom of the plastic container as shown in the picture. A tin layer of grease was used in order to provide good acoustic coupling. Threshold level is the level of the output signal from the sensor above which it will be processed further by the system.