1 Clinker / ciment Techniques de caracterisation

Techniques de caracterisation

• Clinker / ciment

• Pâte de ciment / béton – Solide

– pores

Clinker / ciment

• Composition chimique:

– XRF

• Fast

• All elements (B and above)

X-ra ys

20 µm

« alite » C

S, impure

« belite » C

S, impure

phases

«interstitielles»

« celite » C

A, impure + solution solide de ferrite

« C

AF », liquide pendant la cuisson

X-ray diffraction -Braggs law

10 20 30 40 50 60

0 100 200 300 400 500 600

Theoretical calculation of a mixture of 50 % Alite and 50 % Belite

Alite Belite

Intensities

25 30 35 40

0 200 400 600 800 1000 1200

Belite: Influence of the preferred orientation on the peak area

No orientation Orientation 0.9 Orientation 0.7 Orientation 0.5

Intensities (counts)

2-Theta (°)

Solid solutions

*

*

Example Alite :

(Ca

Mg

Al

Fe

)

(Si

Al

)O

Similar: Belite, Aluminate and Ferrite

- Preferred orientation effects - Overlapping of peaks - Solid solutions

Limitations of conventional

quantitative XRD-analysis:

Bruit de fond

Différentes méthodes de quantification

B) Méthode surface pic

2-theta (°) Intensité (Cps)

0 500

18.2°

A) Intensité absolue

C) Méthode Rietveld

18 55

X Y

Quantitative XRD analysis

Diffractometer

powder sample

X-RAY beam cut out

BRAGG: n•λ = 2•d•sin Θ x-ray beam d

observed diagram

202530354045505560

0 500 1000 1500 2000 2500

SECAR 71

intensity

2-theta

Atoms / PositionX Y Z Occup.

Mg²⁺ 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 Lattice parameters 4.6330 6.6330 15.0160

calculated diagram

202530354045505560

0 500 1000 1500 2000 2500

SECAR 71

intensity

2-theta

Preliminaries: a) stable running Rietveld software b) precise working control files

10 20 30 40 50

0 100 200 300 400

57.2 wt.-% Alite 18.2 wt.-% Belite 12.2 wt.-% Aluminate 7.1 wt.-% Ferrite 4.4 wt.-% Gypsum 0.9 wt.-% Lime

Portland Cement Observed Intensities Calculated Intensities Difference

Intensities (counts)

2-Theta (°)

Rietveld working principles

The Rietveld method

10 20 30 40 50 60

0 100 200 300

Clinker Port La Nouvelle

Observed Intensities Calculated Intensities Difference

Intens iti es ( counts )

2-Theta(°)

1 2 3 4 5 6 7 50

55 60 65 70 75

80 Samples 1-5:

Clinker Type A Samples 6-7:

Clinker Type B Content of Alite

Rietveld calculation Sample X-rayed in Halle Rietveld calculation Sample X-rayed at LCR Microscopy CTS

Weight-%

Sample No.

1 2 3 4 5 6 7

0 2 4 6 8 10 12

Samples 1-5:

Clinker Type A Samples 6-7:

Clinker Type B Content of Aluminate

Rietveld calculation Sample X-rayed in Halle Rietveld calculation Sample X-rayed at LCR Microscopy CTS

Weight-%

Sample No.

0 2 4 6 8 10

1 2 3 4 5 6 7 8 9

Samples 1 to 9

wt.-%

% gypse dsc

% standard

% gypse rietveld

0 2 4 6 8 10

1 2 3 4 5 6 7 8 9

Samples 1 to 9

wt.-%

% gypse dsc

% standard

% gypse rietveld

0 2 4 6 8 10 12

1 2 3 4 5 6 7 8

Samples 1 to 9

wt.-%

% sh dsc

% standard

% sh rietveld

0 2 4 6 8 10 12

1 2 3 4 5 6 7 8

Samples 1 to 9

wt.-%

% sh dsc

% standard

% sh rietveld

Écarts typiques

6 9

« C 4 AF »

5 9 C 3 A

15 13 C ₂ S

67 59 C 3 S

BOGUE QXDA

À cause des solutions solides Le calcul « Bogue » n’est qu’une estimation

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

Nuclear Magnetic Resonance : : application to application to silicates

silicates

Q

Cement Q

Q

Calcium Silicate Hydrates

Q

Quartz, silica fume

-60 -70 -80 -90 -100 -110 -120 ppm Q

Q

Q

One chemical environement

→ one chemical shift (in ppm) on the

29

Si MR spectrum

29

Si chemical shift table (Engelhardt and Michel)

Q

Q

Q

Characterisation

Characterisation of of ciment ciment : : ^{29 29} Si Si spectrum spectrum

cement Q 0

-140 -130 -120 -110 -100 -90 -80 -70 -60 -50 -40

(ppm)

Q _2p Q ₂ Q ₁

C-S-H

sand and quartz Q ₄

silica fume Q 4

NMR Q2(1Al) indicates Al in C-S-H chains

120

100

80

60

40

20

0

x103

-120 -110 -100 -90 -80 -70 -60 -50

ppm

Q

(1Al) Q

Q

Q

(0Al)

Al subsituting for Si in bridging sites 9/17

cement *

-60 -40 -20 20 40 60 80 100

120 0

140 (ppm)

* = rotating side bands

Al

Aluminium

Aluminium in concretes in concretes : : charactérisation charactérisation by using

by using ^{27 27} Al NMR Al NMR

*

* paste : water + * cement

Si

C-S-H

Ca

Al

Al

AFm ettringite

-60 -40 -20 20 40 60 80 100

120 0

140 (ppm)

Aluminium

Aluminium in concretes in concretes : : charactérisation charactérisation by using

by using ^{27 27} Al NMR Al NMR

partially reacted cement grain

“inner” C-S-H

“outer” or

“undifferentiated”

C-S-H sand (aggregate)

calcium hydroxide (CH)

pores

Sections polie, electron retrodiffusé

Inner C-S-H : C-S-H formed within the boundaries of the former cement grains.

Outer C-S-H : C-S-H formed outside the largest cement grains.

Many microanalyses in precise locations

S/Ca

0 0.05 0.1 0.15 0.2

0 0.05 0.1 0.15 0.2

Al/Ca After heating After 200 days Non-expanding mortar

After 200 days

0 0.05 0.1 0.15 0.2

0 0.05 0.1 0.15 0.2

Al/Ca After heating

S/Ca

Expanding mortar

EXAMPLE

mechanism of expansion

of mortars cured at elevated

temperatures

Overall reaction

• Heat output – calorimetry

SO

=2.6; C

A=10

SO

/C

A=0.88 SO

=3.1; C

A=12.1 SO

/C

A=0.87

SO

=2.2; C

A=10.1 SO

/C

A=0.73

Overall reaction

• Heat output – calorimetry

• Bound water

weight loss 110°C – 800 °C