Spin Continuous Monitoring of Setting and Hardening Process of Cement Paste[1]
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Transcript of Spin Continuous Monitoring of Setting and Hardening Process of Cement Paste[1]
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Spearhead Network for Innovative, Clean and
Safe Cement and Concrete Technologies
Continuous Monitoring of Setting and
Hardening Process of Cement Paste
by Means of Elastic Waves
Nenad BijeliDepartment of Materials
Faculty of Civil EngineeringUniversity of Zagreb
Zagreb SPIN Meeting, 7-12 May, 2012
http://www.spin.bam.de/ -
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Outline
background acoustic emission /ultrasoud
fundamentals of AE maesurement measurement system
AE data analysis
application example early agemonitoring of cement paste
Zagreb SPIN Meeting, 7-12 May, 2012
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Background to acoustic emission
!!!crack
Ed>Rd
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Background to acoustic emission
Seismology
AndrijaMohorovii
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Background to acoustic emission
Acoustic Emission - the release of transient elastic waves produced by arapid redistribution of stress in a material
crack nucleation
detection of AE
wave
propagation of
generated AE wave
propagation
of sonic wave
[adapted from Grosse,C.U.; Ohtsu, M.: Acoustic Emission Testing]
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Fundamentals of AE measurement
Measurement system
AE sensor AmplifierFrequency
filtersPC
sample
usually PZT
resonance type broadband type
band-pass filter
threshold
Sourcegenerator
RILEM TC 185-ATC: Final Report (2005)
RILEM TC 212-ACD: Final Report (2010)
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Fundamentals of AE measurement
Data analysis
[adapted from Grosse,C.U.; Ohtsu, M.: Acoustic Emission Testing]
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Early age monitoring of cement paste
setting and hardening processes are the most criticalphases during construction significant influence on
properties of concrete structure
necessary to monitor setting and hydration maturitymethod can be augmented by other methods to obtain amore comprehensive picture of the hydration process
and setting times
e.g. ultrasonic measuring techniques
shear waves [Vali 2000 // Voigt, Shah 2004] longitudinal waves [Reinhardt, Grosse 2004 // Kraus,
Hariri 2006 // Mikuli et al. 2006 // Gabrijel et al. 2009]
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Early age monitoring of cement paste
continuous monitoring possible
[adapted from Kamada et al. 2005]
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Early age monitoring of cement paste
experiment scheme
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Early age monitoring of cement paste
experiment scheme
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Early age monitoring of cement paste
hydration of cement paste was monitored
transformation from liquid to solid state characterised with twopoints in hydration time: initial setting & final setting
development of strength and stiffness
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Early age monitoring of cement paste
goals of our research:
get measurement system to work
identify ultrasonic wave parameters that could, by virtue of theirtrend, be indicative of or used to represent period of setting and
period of hardening of cement paste
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Early age monitoring of cement paste
materials and mixture proportions
Properties of CEM I 42.5R cement
w/c ratios 0.4, 0.5 and 0.6 mixing procedure HRN EN 196-3 Vicat needle test HRN EN 196-3
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Early age monitoring of cement paste
Setting of cement paste: liquid solid
parameters that significantly change during the transformation:
duration time from the first threshold crossing to the end of thelast threshold crossing of the signal in one wave
risetime time between the first threshold crossing and thepeak amplitude of the signal in one wave
both parameters start to change before any change in
the Vicat penetration test can be observed w/c ratio has influence on both parameters the change
in parameter starts at a later time with the increase in w/c
ratio (linear correlation)
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Early age monitoring of cement paste
several maxima andminimaproblematic
contact between thetransducer and specimen
first maximum at the ageclose to the final setting
time
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Early age monitoring of cement paste
relatively low values forall cement pastes at the
beginning of ultrasonicsignal appearance
the end of a suddenincrease/decrease close
to the final setting time
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Early age monitoring of cement paste
Hardening of cement paste
from the analysis of the ultrasonic signal, two parameters werefound to show different trends during hydration which seem to be
related to changes other than the transformation from liquid to solidstate:
ultrasonic pulse velocity (UPV) specimen length / time of flight
signal strength integral of the rectified voltage signal over theduration of the waveform
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Early age monitoring of cement paste
impulses transfered onlyafter a certain age high
absorption of the material
in the liquidmash state
UPV reciprocal to w/c ratio
final setting time appears atthe speed around 1300 m/s;
the influence of w/c ratio
on UPV becomes evident
afterwards
UPV primarily influencedby cement paste stiffness
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Early age monitoring of cement paste
signal strength reciprocal tow/c ratio
larger scattering observedthan in the case of UPV
possible that signal strengthis governed by different
processes than UPV
signal strength more closelyrelated to microstructure,
morphology, porosity andmicrocracs of material [Vary,
1988]; influence of shrinkage
on the amount of transfered
energy
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Concluding remarks
active ultrasonic technique enables continuousmonitoring of cement paste at early age thus providing a
more comprehensive picture of cement paste hydration
parameters extracted from the waveform (e.g. duration,risetime, signal strength) are indicative of the processes,
i.e. setting and hardening, in the cement paste during
hydration
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References
[1] Vali, M.I. Hydration of cementations materials by pulse echo USWR: Method, apparatus and application examples. // Cement andConcrete Research. 30, 10(2000), str. 1633-1640.
[2] Voigt, T.; Shah, S. P. Properties of early age Portland cement mortar monitored with shear wave reflection method. // ACI Materials
Journal. 101, 6(2004), str.473-482.
[3] Reinhardt, H. W.; Grosse, C. U. Continuous monitoring of setting and hardening of mortar and concrete // Construction and building
materials, 18 (2004), str. 145-154.
[4] Krauss, M.; Hariri, K. Determination of initial degree of hydration for improvement of early-age properties of concrete using ultrasonic
wave propagation. // Cement and Concrete Composites. 28, 4(2006), str. 299306.
[5] Mikuli, D.; Sekuli, D.; tirmer, N.; Bjegovi, D. Application of ultrasonic methods for early age concrete characterisation. //
International Journal of Microstructure And Materials Properties. 1, 3/4(2006), str. 297-309.[6] Gabrijel, I.; Mikuli, D.; Milovanovi, B. Application of Ultrasonic Measurements for Determination of Setting and Hardening in
Cement Paste. // Construction in the 21st Century CITC-V / edited by Birgonul, M.T. et al. Istanbul : Florida International University,
Miami, Florida, U.S.A. and Middle East Technical University, Ankara, Turkey, 2009. str. 1420-1426.
[7] Van Breugel, K. Simulation of Hydration and Formation of Structure in Hardening Cement-Based Materials. Delft Univ.Press, Delft,
1991.
[8] Mikuli, D.; Milovanovi, B.; Gabrijel, I. Testing of Compressive and Bending Strength of Concrete and Monitoring Acoustic EmissionParameters. // 7th International Symposium on Non-destructive Testing in Civil Engineering / Abraham, O and Derobert, X. (ur.).
Nantes : Laboratoire Central des Ponts et Chaussees, 2009. str. 903-908
[9] Philippidis, T. P.; Aggelis, D. G. An Acousto-Ultrasonic Approach for the Determination ofWater-to-Cement Ratio in Concrete,Cement and Concrete Research, 33 4(2003), 525-538.
[10] Vary,A. The acousto-ultrasonic approach. // Duke J. C. (Ed.) / Acousto-Ultrasonics: Theory and Application. Plenum Press,
NewYork, 1988., str 1-21
[11] Voigt, T. The Application of an Ultrasonic Shear Wave Reflection Method for Non-destructive Testing of Cementbased Materials at
Early Ages: An Experimental and NumericalAnalysis, PhD thesis, University of Leipzig, 2004.
[12] Mehta, P. K.; Monteiro, P. J. M. Concrete - microstructure, properties and materials, third edition, The McGraw-Hill Companies
Inc.,NewYork, 2006.
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The End
Thank you!