Spin Continuous Monitoring of Setting and Hardening Process of Cement Paste[1]

7/28/2019 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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Seismology

AndrijaMohorovii


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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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continuous monitoring possible

[adapted from Kamada et al. 2005]


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experiment scheme


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experiment scheme


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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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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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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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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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several maxima andminimaproblematic

contact between thetransducer and specimen

first maximum at the ageclose to the final setting

time


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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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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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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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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!

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Spin Continuous Monitoring of Setting and Hardening Process of Cement Paste[1]