Short Course Concrete (Prof. Gondal)

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4/22/2012 1

Assessment of Concrete Using

Laser Induced BreakdownSpectroscopy (LIBS)

Dr. M. A. GondalPhysics Department



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Outline

• Introduction (corrosion and significance of its monitoring)

• Principle of LIBS

• Experimental Setup

• Results and Discussions

• Applications of LIBS

• Conclusions



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Motivation of Concrete Assessment



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Concrete Evaluation

• The chloride content is an important criterionfor evaluation of the durability of reinforcedconcrete (or corrosion occurrence)

• Normal techniques needs chemical laboratory,a lot of sample preparation, chemicals and aretime consuming so advanced techniques (freeof above mentioned logistics) are worth

investigating for concrete inspection.



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Advantages of LIBS No Sample or little preparation is needed which makes the system

cost effective and less time consuming

All states of mater can be analyzed, as well as both conductive andnonconductive samples.

Very small amount of sample is vaporized

Capability of remote analysis, in harsh environments.

Atomization and excitation are in one step.

Capable of simultaneous multi-element analysis.

LIBS has a preferably simple set-up, and it is most suitable forapplications in harsh environments, for process control and for on-

site measurements

Applications of LIBS for the investigation of building materials are

the detection of hydrophobic



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Laser induced plasma

Principle of LIBS

Fiber optic

Pulsed laser

Atomic emission lines

provide species identificationsample

Detector

Spectrometer

410 415 420 425 430 435 44

Wavelength (nm)

E m

i s s i o n I n t e n s i t y



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Plasma plume



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12

Focusing lens

Laser beam

Plasma plume

Regime 1: 1-10 ns Plasma

ignition Thermal and

multiphoton ionization

EI

E1

EK

Ei

E0

Unspecific

transitions

Some 100 nsrecombination

EI

E1

EK

Ei

E0

Atomic line

emissions

Some μs

relaxations



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Material

Heating of material

Evaporation of material

Dissociation of molecules

Absorption of laser

Plasma ignition

Heating of plasma

Plasma expansion

High power

laser pulse

Plasma plume

Focusing lens

Evolution of laser induced plasma material



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Ei

Ef

Atomic and molecular transitions at different times

depending on the breakdown thresholds for elements



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430 440 450 460 2000

6000

10000

14000

18000

22000

26000

i n t e n s i t y

( a . u

)

Wavelength (nm)

1.5μs

0.5μs0.0μs

2.5μs

Time evolution of the emission spectra of steel sample in the region of 415-445 nm



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415 420 425 430 435 440

25000

30000

35000

40000

45000

50000

55000

60000

i n t e n s i t y ( a . u

)

wavelength(nm)

415 420 425 430 435 440

25000

30000

35000

40000

45000

50000

55000

60000

i n t e n s i r t y ( a . u

)

wavelength(nm)

415 420 425 430 435 440

25000

30000

35000

40000

45000

50000

55000

60000

i n t e n s i t y ( a . u

)

wavelength (nm)

415 420 425 430 435 440

25000

30000

35000

40000

45000

50000

55000

60000

i n t e n s i t y

( a .

u )

wavelength (nm)

0.5μs

1.5 μs

2.5 μs

3.5 μs



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Experimental setup

Laser system (1064 nm, 10 Hz)

Optical detection system

Synchronization system

Samples (crude oil, soil, iron slag, ore, plastics,paint , cement, water etc)



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Optical fiber

ICCD

LIBS 2000

Spectrometer

POWER

METER

Nd:YAG LASER

Laser

power supply

Beam attenuator B.S Lens Sample on a

rotary stage

Fig. Schematic diagram of LIBS

Setup

Oscilloscope



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Line intensity

When the optical transition occurs between two energy

levels, the intensity of spectral line is given by

(1)

T K

E hcgAN I

B

exp4



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Quantitative Analysis

Parametric Dependence

Calibration Curves

Limits of Detections

Analysis



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LIBS Parametric Dependences

and System Calibration



0

50

100

150

200

250

300

350

400

450

500

550

600

400 450 500 550 600 650wave Length (nm)

S i g n a l I n t e n s i t y

( a r b . u

n i t )

Ca(442.5 nm)

Ca(443.9 nm)

Ca(445.4 nm)

Ca(422.8 nm)

Na(588.9 nm)

Ca(612.2 nm)Ca(610.2 nm)

K (404.41 nm)

Ca(527.02 nm)

Ca(558.6 nm)

Typical LIBS Spectra of Calcium in KBr matrix in the region of400 to 650 nm recorded at delay time of 4.5 µs and laser pulse energy of 25 mJ.



0

500

1000

1500

2000

2500

3000

3500

4000

400 450 500 550 600 650

Wave Length (nm)


( a r b . u n i t )

K (404.41 nm)

Mg (518.36 nm)

Mg (517.27nm)

Mg (516.73 nm)

Br (470.4nm)

Mg ii (448.113 nm)

S (550.97 nm)

Na (588.99nm)

Typical LIBS Spectra of Mg in KBr matrix in the region of 400 to 650 nmrecorded at delay time of 5 µs and laser pulse energy of 25 mJ.



Ca ( 393.368 nm )

R2

= 0.9965

0

500

1000

1500

2000

2500

3000

3500

10 15 20 25 30 35

Laser pulse Energy (mJ)

S i

n a l I n t e n s i t

( a r b . u

Plot of dependence of the intensity of the Mg 518.36 nm emission

line on laser energy



0

60

120

0.00 1.00 2.00 3.00 4.00 5.00 6.00 7.00 8.00

Time Delay (µs)


( a r b . u n i t s )

Fig . Dependence of LIBS signal intensity on the delay timefor trace metal (Zn) present in the oil residue sample.



R2

= 0.9943

800

900

1000

1100

1200

1300

1400

1500

2000 4000 6000 8000 10000 12000 14000

Pressure Applied (Ib/Sq.In.) for Pellets Formation

S i g n a

l

I n t e n s i t y

( a r b . u

)

Dependence of the Emission line intensity of a Mg 518.36 nm lineon the amount of pressure used to make the pellets



0

500

1000

-4 -2 0 2 4 6

Distance from Focal Point for the Focusing Lens (mm)

I n t e n s i

t y

( a r b u

n i t s )



R2 = 0.9983

200

300

400

500

600

700

800

900

1000

1100

7 9 11 13 15 17 19 21 23 25

Coll ecting Lens Distance from Target Surface (mm)


( a r b . u )

Variation of the intensity of the Mg 518.36 nm emission line with the change in theposition of collecting lens from the sample. The maximum signal is recorded at

a distance = 10 mm equal to the focal length of the collecting lens.



R2

= 0.9975

450

500

550

600

650

700

750

800

850

2 4 6 8 10 12 14

Target Rotator Speed (rpm)


( a r b . u

)

Variation of the intensity of the Mg 518.36 nm emission linewith the target rotation speed.



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The intensity of a spectral line ‘I’ from an excited atomor ion in homogenous and optically thin plasma for atransition from state j --- i is given by:

I = h ji A ji N g j Q-1 exp (-E j /kT)

ji = frequency of the transition from state j --- i

A ji = Einstein coefficient for spontaneous emissionN = population density of ground stateh = Planks constant

Q = Partition function

E j =energy of upper level

By plotting the intensity versus concentration, one candetect the unknown concentration from a linear plot forsame element. such plot is called calibration curve



R2 = 0.9996

1

10

100

1000

10000

10 100 1000 10000 100000

Concentration (ppm)


( a r b . u

n i t s )

Calibration curve for LIBS measurements of trace metal (magnesium).The curve was plotted by recording the LIBS signal intensity of the Mg 518.36 nmemission line at various known concentration in standard samples of magnesium.



Concentration Vs Signal Intensity (Pb)

1

10

100

1000

10000

10 100 1000 10000 100000

Concentration (ppm)

S i g n

a l I n t e n s i t y

( a

r b . u n i t )

Calibration curve for LIBS measurements of trace metal (Pb). The curve wasplotted by recording the LIBS signal intensity of the Pb 405.78 nm emissionline at various known concentration in standard samples of lead.



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Limit of Detection

The detection limit (LOD) can be estimated usingthe equation:

LOD = 2b / S

b = the standard deviation of the back ground

S = Sensitivity given by the ratio of the intensity

to the concentration

= Slope of the calibration curve

Limit of Detection of Our LIBS



Limit of Detection of Our LIBS

SetupElement Wavelength

(nm)

LOD(ppm) Delay (μs)

Mg 518.36 9 5

Pb 405.78 7 5.5

Cu 521.82 4 4.5

Ca 422.6 14 5

Fe 404.58 12 4.5

Zn 492.4 5 5

Na 589.5 10 4Ni 480.66 11 4.5

K 404.41 4 4

Mo 553.56 2 5.5

Cr 425.43 7 5.5

Mn 403.44 6 4.5

P 255.32 4 4.5S 547.92 7 4.5

Si 250.6 10 4

Sr 460.73 7 4.5

Ti 399.8 10 5

V 440.85 5 4.5

Al 460.98 12 4

Ba 553.54 14 5.5



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LIBS Applications



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ANALYSIS OF

CEMENT SAMPLES



LIBS Analysis of Cement Type I Sample

Cement Type I

0

50

100

150

200

250

300

350

400

200 250 300 350 400 450 500 550 600

Wave Length (nm)

S i g n a l I n t e n s i t y ( a r b . u

n i t

Cl Al Cr S Ba

Mg

P

Ca

Ca

Cl

NaCa

Ca

MnP

Fe

C S

ClCa



LIBS Analysis of Cement Type V Sample

Cement Type V

0

20

40

60

80

100

120

140

160

200 250 300 350 400 450 500 550 600

Wave Length (nm)

S i g n a l I n t e n s i t y ( a r b . u n i t

Fe Cl S

Ca

P

S Ba

M

Fe

P

F

CCa Ca

Cl

Cr

Ca

Si



Cement Type SF

0

100

200

300

400

500

600

200 250 300 350 400 450 500 550 600

Wavelength (nm)

S i g n a l I n t e n s i t y ( a r b . U n i t )

Ca

Na

Mg

ClAlAl

Si

Fe

Na

Mg

Si

Ba

Al

Ca

Cl

Cr

Cr Ba

Cl

PS

Si

LIBS Analysis of Cement Type SF Sample



Table 1: Elements detected in cement samples and comparison of LIBS Technique with ICP

Elemen

t

Wave

-

length

(nm)*

Cement

Type I Cement

Type V Cement

Type SF LOD

(ppm)

Delay

(μS)

LIBS

(ppm) ICP

(ppm) LIBS

(ppm) ICP

(ppm) LIBS

(ppm) ICP

(ppm)

Al 394.4 34500 34100 24350 24200 521.4 474 8.0 4.5

Ba 493.4 6280 6080 6731 6620 nd nd 5.0 5.0

Ca 396.1 433500 433000 443480 443000 2090 2043 6.0 5.0

Cr 427.3 96.58 87.8 Nd* Nd* Nd* Nd* 4.0 5.5Fe 526.9 20230 19300 21980 21200 396 366 7.0 3.5

Mg 518.2 8017 7470 13905 13400 2801 2700 2.0 4.5

Mn 403.4 226.6 206 306.9 279 510.1 475 4.0 4.5

Na 588.9 3211 3010 3977 3680 2852 2760 3.0 3.5

P 438.5

1

Nd* Nd* Nd* Nd* 825.3 783 7.0 4.5

S 373.8

1

11320 11000 8480 8080 304.7 277 10.0 4.0

Si 390.5 92020 88200 81600 81200 351590 349000 11.0 4.5

Cl 585.7 1825 1720 1590 1520 6690.7 6595 12 5.0

*Reference for wavelengths: A. Striganove, and N. Sventitski, Table of Spectral Lines of Neutraland Ionized Atoms (Plenum New York) 1968 and NIST data base [35]

Nd* : Not detected



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Depth Profiling Using LIBS



Depth Profiling with LIBS for Chloride Content (Wiggenhauser et al, 2005)



Comparison of the Results from standard chemical analysis and the results from

LIBS measurements on the cores (Wiggenhauser et al, 2005)



Comparison of Glow Discharge Optical Spctroscopy (GD-OES)with LIBS measurements (Laserna et al 1998))



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Plasma Plume

SampleHolder

Sample

(a) Plasma Plume at 25mJ (b) Plasma Plume at 30mJ

(c) Plasma Plume at 35mJ (d) Plasma Plume at 40mJ

Fig. Images of Laser induced plasma of ore sample at laser

pulse energy of 25,30,35.40 mJ



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LIBS R S i



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LIBS Remote Sensing

R



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Other LIBS Applications

• Pollution monitoring (contaminants in liquids,

solid and gaseous samples).

• Trace element analysis of air, soil and water.

•

Immediate determination of ore grades duringmining and prospecting and industrial chemical

process control.

• Chemical analysis of planetary boundary layers

such as Mars etc.

• Chemical analysis of terror agent such as

explosives, strains of anthrax-surrogate bacteria.



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Conclusions

• The results achieved in this study show that LIBStechnique is applicable for the detection of chlorineand other trace elements present in different cementand concrete samples

• The technique holds promise of wider utility becauseof its applicability under diverse conditions such asfor the remote analysis or in situ analysis, ofconcrete and other metallic structures, depth

profiling and multi-elemental analysis.

Our Publications on LIBS



Our Publications on LIBS

1. Gondal, M. A. T. Hussain (2007), Determination of Poisonous Metals in Waste Water collected fromPaint Manufacturing Plant Using Laser- Induced Breakdown Spectroscopy TALANTA Vol 71, 73-80.

2. Gondal, M. A, T. Hussain, Z. H. Yamani and A.H. Bakry (2007), Determination of Elemental Compositionin Iron Slag Waste Using Laser Induced Breakdown Spectroscopy, J. Environment Science and HealthVol. 42, No. 6,767-775 (2007).

3. Gondal, M. A. M. N. Siddiqui (2007), Identification of Different Kinds of Plastics Using Laser InducedBreakdown Spectroscopy for Waste Management, J. Environment Science and Health Part A ,Vol 42,No13 (2007).

4. Gondal, M. A, T. Hussain, Z. H. Yamani, M. A. Baig (2007), The Role of Various Binding Materials forTrace Elemental Analysis of Powder Samples Using Laser Induced Breakdown Spectroscopy, Talanta,Vol 72, 642-649.

5. Gondal, M. A T. Hussain, Z. Ahmad, A. Bakry, (2007), Detection of Contaminants in Ore Samples UsingLaser Induced Break Down Spectroscopy, J. Environment Science and Health Part A Vol. 42, No. 7 ,879-887 (2007)

6. T. Hussain, M. A. Gondal (2007), Detection of toxic metals in Waste water from Dairy Product Plantusing Laser Induced Breakdown Spectroscopy, Bulletin Of Environmental Contamination & Toxicology(accepted and in press ).

7. T. Hussain, M. A. Gondal (2007), Monitoring and Assessment of Toxic Metals in gulf war oil spillcontaminated soil using Laser- induced Breakdown Spectroscopy, Environmental Monitoring andAssessment (on line available on April 6, 2007, 10.1007/s10661-007-9694-2).

8. Gondal, M. A. T. Hussain, and Z. H.Yamani (2007), Parametric investigation of Pellets for Trace Metals

Detection using Laser-Induced Breakdown Spectroscopy, Energy Sources Part A- Environment(accepted and in press).

9. Gondal, M. A. T. Hussain, Z. H.Yamani and Z. Ahmad (2007), Analysis of Oil, Soil and Ore Samplesusing Laser Induced Breakdown Spectroscopy, Bulletin Of Environmental Contamination &Toxicology, Vol 78, 270-274.

10. T. Hussain, Gondal, M. A. and Z. H.Yamani (2007), Measurement of Nutrients in Green House Soil withLaser Induced Breakdown Spectroscopy, Environmental Monitoring and Assessment Vol 124, 131-139.

11. Gondal, M. A. T. Hussain, Z. H.Yamani, M.A. Baig (2006), Detection of Heavy Metals in Arabian CrudeOil Residue using Laser Induced Breakdown Spectroscopy, TALANTA, Vol 69, 1072 .

Two papers listed in Top 25 Hottest papers

Th k Y !



4/22/2012

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Short Course Concrete (Prof. Gondal)

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