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Analysis of Moisture Flow in Porous Building Materials Using X-ray Radiography
Tine van Besien
Staf Roels
Jan Carmeliet
Laboratory for Building Physics, Department of Civil Engineering
Analysis Moisture Phenomena
- weighing of samples
- moisture profiles --> destructive way
- -ray attenuation technique
- NMR-technique
...
Non-destructive methods:
--> measure point wise, interpolation time domain necessary
X-ray Radiography
)exp(0 oodry dII
)exp(0 wwoowet ddII
)exp( wwdry dI
)exp(w
owdrywet
dwII
)exp( wwdrywet dII
o
ww
o
ww
d
d
V
Vw
dry
wet
ow
w
I
I
dw ln
Resolution
dryw
ww IdR
11ln
Function of:
- material
- energy of the source
- sample thickness
calibration measurements
0
1
2
3
4
0 0.05 0.1
sample thickness d (m)
-ln(I/
Io)
waterceramic brickcalcium silicate plate
eq
Attenuation coefficients
0)(
d
ERw
w
w
w
woptd
1ln
0
2
4
6
8
10
12
14
0 0.005 0.01 0.015 0.02 0.025 0.03
sample thickness d (m)
reso
lutio
n R
w (
kg/m
³)
increasing energy
CERAMIC BRICK
50 keV
60 keV
85 keV
d opt
0
1
2
3
4
5
0 0.05 0.1 0.15 0.2 0.25
sample thickness d (m)
reso
lutio
n R
w (
kg/m
³)
increasing energy
CALCIUM SILICATE
70 keV
100 keV
85 keV
d opt
Experiments
- determination of moisture profiles
- redistribution of hydrophobic agent in material
- cracks
- heterogeneous materials
1D
2D
-100
0
100
200
300
400
500
600
700
800
900
0 0.01 0.02 0.03 0.04 0.05 0.06 0.07
distance (m)
mo
istu
re c
on
ten
t (k
g/m
³)
Redistribution water-repellent
-5.00E-03
0.00E+00
5.00E-03
1.00E-02
1.50E-02
2.00E-02
2.50E-02
15 25 35 45 55 65 75 85
Aerated concrete
Crack in Brick Sample
Crack in Calcium Silicate sample
ProblemsUnstable source
-6.00E-01
-5.00E-01
-4.00E-01
-3.00E-01
-2.00E-01
-1.00E-01
0.00E+00
1.00E-01
2.00E-01
1 21 41 61 81 101
121
141
161
181
201
221
241
261
281
301
321
341
361
381
401
421
441
461
481
501
521
541
561
581
601
621
641
-0.6
-0.5
-0.4
-0.3
-0.2
-0.1
0
0.1
0.2
0 100 200 300 400 500 600 700
-0.01
0
0.01
0.02
0.03
0.04
0.05
150 200 250 300 350 400 450 500
Reflections?
-2.00E-02
0.00E+00
2.00E-02
4.00E-02
6.00E-02
8.00E-02
1.00E-011 14 27 40 53 66 79 92 105
118
131
144
157
170
183
196
209
222
235
248
261
274
287
300
313
326
339
352
365
378
391
404
417
430
443
456
469
482
495
Combination
-0.05
0
0.05
0.1
0.15
0.2
0 100 200 300 400 500 600
Future experiments- water penetration through hydrophobic treated crack
- drying of crack