Techniques de caracterisation Clinker / ciment - Cours de Génie Civil

Techniques de caracterisation
• Clinker / ciment
• Pâte de ciment / béton
– Solide
– pores
Clinker / ciment
• Composition chimique:
– XRF
• Fast
• All elements (B and above)
X-rays

20 µm
«alite»
C 3 S, impure
« belite »
C 2 S, impure
phases
«interstitielles»
«celite»
C 3 A, impure
+ solution
solide de ferrite
«C 4 AF »,
liquide pendant
la cuisson
X-ray diffraction -Braggs law
Limitations of conventional
quantitative XRD-analysis:
1200
Belite: Influence of the preferred orientation on the peak area
- Preferred orientation effects
- Overlapping of peaks
- Solid solutions
Intensities (counts)
1000
800
600
400
200
0
No orientation
Orientation 0.9
Orientation 0.7
Orientation 0.5
25 30 35 40
2-Theta (°)
Theoretical calculation of a mixture of 50 % Alite and 50 % Belite
Solid solutions
*
Example Alite :
(Ca 0,98 Mg 0,01 Al 0,067 Fe 0,00333 ) 3 (Si 0,97 Al 0,03 )O 5
Similar: Belite, Aluminate and Ferrite
Intensities
600
500
400
300
200
Alite
Belite
*
CEMENT CHEMISTRY, H.F.W. Taylor (2nd edition 1997)
100
0
10 20 30 40 50 60
2-Theta (°)

2500
2000
1500
1000
500
0
2500
2000
1500
1000
500
20 25 30 35 40 45 50 55 60
2-theta
0
SECAR 71
SECAR 71
400
300
200
100
20 25 30 35 40 45 50 55 60
2-theta
0
57.2 wt.-% Alite
18.2 wt.-% Belite
12.2 wt.-% Aluminate
7.1 wt.-% Ferrite
4.4 wt.-% Gypsum
0.9 wt.-% Lime
Observed Intensities
Calculated Intensities
Difference
10 20 30 40 50
2-Theta (°)
Quantitative XRD analysis
Intensité (Cps)
Différentes méthodes de quantification
C) Méthode Rietveld
A) Intensité absolue
500
B) Méthode surface pic
18 55
0
X
18.2°
Y
Bruit de fond
2-theta (°)
Rietveld working principles
Diffractometer BRAGG: n•λ = 2•d•sin Θ
X-RAY beam
cut out
d
x-ray beam
observed diagram
intensity
powder
sample
Portland Cement
Intensities (counts)
Atoms / Position X Y Z Occup.
calculated diagram
Mg 2+ 0.000 0.000 0.000 0.1667
C 0.000 0.000 0.000 0.1667
O 1- 0.2800 0.000 0.2500 0.5000
intensity
Lattice parameters 4.6330 6.6330 15.0160
Preliminaries: a) stable running Rietveld software
b) precise working control files
The Rietveld method
Clinker Port La Nouvelle
300
Observed Intensities
Calculated Intensities
Difference
Intensities (counts)
200
100
0
10 20 30 40 50 60
2-Theta(°)

1 2 3 4 5 6 7
Weight-%
Content of Alite
80
Samples 1-5:
Clinker Type A
75
Samples 6-7:
Clinker Type B
70
65
Rietveld calculation
60
Sample X-rayed in Halle
Rietveld calculation
Sample X-rayed at LCR
55
Microscopy CTS
50
Sample No.
Weight-%
Content of Aluminate
12
Rietveld calculation
10
Sample X-rayed in Halle
Rietveld calculation
Sample X-rayed at LCR
8
Microscopy CTS
6
4 Samples 1-5:
Clinker Type A
2 Samples 6-7:
Clinker Type B
0
1 2 3 4 5 6 7
Sample No.
wt.-%
wt.-%
10
10
8
8
6
6
4
4
2
2
0
0
% gypse dsc
% gypse dsc
% standard
% standard
% gypse rietveld
% gypse rietveld
2 3 4 1 5 6 7 8 9
1 2 3 4 5 6 7 8 9
Samples 1 to 9
Samples 1 to 9
wt.-%
wt.-%
12
12
10
10
8
8
6
6
4
4
2
2
0
0
% sh dsc
% sh dsc
% standard
% standard
% sh rietveld
% sh rietveld
1
1
2
2
3
3
4
4
5
5
6
6
7
7
8
Samples
8
Samples
1
1
to
to
9
9
À cause des solutions solides
Le calcul « Bogue » n’est qu’une
estimation
C 3 S
BOGUE
59
QXDA
67
C 2 S
C 3 A
«C 4 AF »
13
9
9
15
5
6
Écarts typiques
Pâte de ciment / béton - solids
Hydrates
• Hydroxides de calcium, Ca(OH) 2
• C-S-H ?

NMR – RMN – resonance magnetic nucleaire
• Nucleus with non-zero magnetic moment
• Strong magnetic field,
strong radio frequency pulse aligns nagnetic
moments
• Magnetic moments relax back to equilibrium
positions
• Fourier transform of time dependency >
frequency spectrum
Nuclear Magnetic Resonance : application to
silicates
One chemical environement
→ one chemical shift (in ppm) on the
29 Si MR spectrum
Q 0
Q 1
Q 2
29 Si chemical shift table
(Engelhardt and Michel)
Q 3
Q 0
Cement
Q 4
-60 -70 -80 -90 -100 -110 -120
ppm
Q 3
Q 2
Q 1
Calcium Silicate
Hydrates
Quartz, silica
fume
Q 4
Characterisation of ciment : 29 Si spectrum
Q 1
C-S-H
Q 2
Q 2p
cement
sand and quartz Q 4
Q 0
-140
silica fume Q 4
-40
-50
-60
-70
-80
-90
-100
-110
-120
-130
(ppm)

NMR
Q2(1Al) indicates Al in
C-S-H chains
120
100
80
Q 2 (1Al)
Q 0
Q 1
Q 2 (0Al)
x10 3
60
40
20
0
-50
-60
-70
-80
-90
ppm
-100
-110
Al subsituting for Si
in bridging sites
-120
9/17
Aluminium in concretes : charactérisation
by using 27 Al NMR
Al IV
cement *
140
120 100 80 60 40 20 0
(ppm)
-20
-40
-60
* = rotating side bands
C-S-H
Aluminium in concretes : charactérisation
by using 27 Al NMR
Si
ettringite
Ca
AFm
Al V
Al IV
paste : water +
cement
140
*
120 100 80 60 40 20 0
(ppm)
*
*
-20
-40
-60
* = rotating side bands

Sections polie, electron retrodiffusé
pores
sand (aggregate)
“outer” or
“undifferentiated”
C-S-H
“inner” C-S-H
partially reacted
cement grain
calcium hydroxide
(CH)
Many microanalyses in precise locations
Outer C-S-H :
C-S-H formed
outside the largest
cement grains.
Inner C-S-H :
C-S-H formed within
the boundaries of the
former cement grains.
EXAMPLE
mechanism of expansion
of mortars cured at elevated
temperatures
0.2
Non-expanding mortar
S/Ca
0.15
0.1
0.05
0
After heating
After 200 days
0 0.05 0.1 0.15 0.2
Al/Ca
S/Ca
0.2
0.15
0.1
0.05
0
Expanding mortar
After heating
After 200 days
0 0.05 0.1 0.15 0.2
Al/Ca

Overall reaction
• Heat output – calorimetry
SO 3 =2.6; C 3 A=10
SO 3 /C 3 A=0.88
SO 3 =3.1; C 3 A=12.1
SO 3 /C 3 A=0.87
SO 3 =2.2; C 3 A=10.1
SO 3 /C 3 A=0.73
Overall reaction
• Heat output – calorimetry
• Bound water
weight loss 110°C – 800 °C