impact of some parameters in cement production on ... o is mainly determined by dynamic ... setting...

1 / 03.03 Smart Minerals GmbHSchneider

Impact of some parameters in cement production on rheological properties of cement paste

Ameneh Schneider Stefan RatzingerAlexander Marcini


Contents

State of the art

Pilot tests and results

Main tests

Results

• Flow diagrams

• Evaluated plastic viscosity - yield stress (Bingham model)


Rheological Investigations

Definition:

• is the science of deformation and flow character of matter.

Rheology in cement based systems is determined by:

• Plastic viscosity

o A property of fluids in movement

o Is mainly determined by dynamic friction between moving elements

• Yield stress

o A property of the fluid at shear rate zero, mainly influenced by attractions and physical networking of two or more component

o Variations of the first hydration products of cement affect these forces

Bingham

0τγητ +×=


State of the art relating to cement paste and rheological investigations • Depending on the clinker and sulphate retarding the

composition of the pore solution changes change of rheological behavior (the dispersing force of super plastizier degrade by the sulfate ion)

• Structure of plasticizer change the rheological performance

• Cement types with blast furnace slag or limestone shows in general better workability need lower concentration of plasticizer

• The choice of the plasticizer for the best performance (fluidity and stability) is essential


Instrument for Investigations on cement paste Rheometer is an appropriate instrument (tool) for

• Characterization or description of the flowability,

• Determining the yield stress values

• Viscosity of the cement pastes

• Comparison of the effect of different plasticizers such as Polycarboxylate ether-based (PCE) superplasticizer with different structures

• Determination of the most effective concentration of superplasticizer

• Determination of the influence of various factors on the rheological characteristics such as temperature (winter/summer) or variation in cement production

useful for

Viskomat NT


Pilot tests

Objectives of the pilot tests:

• Which factors are critical for measurements with Viskomat NT?

• How is the repeatability of measurements?

• What is the appropriate measuring profile constant shear stress, step load

• Sample preparation

o Mixing tool

o Mixing time

o W/C ratio

• Storage of materials in a room with constant temperature and air humidity


20

40

60

80

100

120

140

160

180

200

220

0

0,6

4

1,2

7

1,9

2,5

4

3,2

2

3,9

2

4,5

9

5,2

5 6

6,7

4

7,4

8

8,1

6

8,8

9,4

3

10

,1

10

,7

11

,3 12

12

,6

13

,2

13

,9

14

,5

15

,1

15

,8

16

,4

Zeit [Min]

Dre

hm

om

ent

[Nm

m]

Time [min.]

To

rqu

e [

Nm

m]

Flow diagrams of pilot tests

Measuring profil 1

20

40

60

80

100

120

140

0,0

1

0,6

8

1,3

4

2,0

1

2,6

8

3,3

5

4,0

1

4,6

8

5,3

5

6,0

2

6,6

8

7,3

5

8,0

2

8,6

9

9,3

5

10

10

,7

11,4 12

12,7

13

,4 14

14,7

15,4 16

16,7

17,4

Zeit

Ges

chw

ind

igke

it

shear profil


20

40

60

80

100

120

140

160

180

200

220

240

260

280

300

320

340

360

380

0,0

0,7

1,3

2,0

2,7

3,3

4,0

4,7

5,4

6,0

6,7

7,4

8,0

8,7

9,4

10

,0

10

,7

11

,4

12

,0

12

,7

13

,4

14

,0

14

,7

15

,4

16

,0

16

,7

17

,4

Zeit [Min]

Dre

hm

om

ent

[Nm

m]

Time [min.]

To

rqu

e [

Nm

m]

Variation in W/C ratio

W/C = 0,35

W/C = 0,40

W/C = 0,45


Drehmoment

0

20

40

60

80

100

120

140

160

180

200

220

240

260

280

300

0,01

3,0

1

6,01

9,01 1

2

15

18 21 24

27

30

33

36

39

42

45

48

51

54

57

60

63

66

69

72

75

78

,1

81

,1

84

,1

87

,1

90

,1

93

,1

96

,1

99

,1

Zeit

Dre

hm

om

ent

M12/0253_0,4_FM1_V1_2006

M12/0253_0,4_FM3_V2_2006

M12/0253_0,4_FM2_V1_3007

Time [min.]

To

rqu

e [

Nm

m]

Estimation of saturating point of plasticizers

1. D

osag

e

2. D

osag

e

3. D

osag

e

4. D

osag

e

5. D

osag

e

6. D

osag

e


Summary of results of pilot tests

Variation of parameter

Type of blender Mortar blender Household blender

Mixing time 90 s 120 s 150 s 180 s

W/C ratio 0,35 0,4 0,45

Measuring time 20 min 45 min 60 min

Shear profile Ramp

Repeatability ± 3,2%

Setting the parameters of the experiments and estimating the repeatability before starting the comparative investigations on

Viskomat NT


Investigated parameters of cement paste – comperative experiments

All investigations run with cement type CEM I 42,5 R

• Influence of fineness in cement production

• Influence of sulfate retarding agent in cement production

• dihydrate / hemihydrates / anhydrite

• Influence of temperature (winter - summer) construction praxis

• Influence of chemical structure of the plasticizer in the market available PCE variations e.g. total chain length, side-chain length, charge density


Different PCE-Molecule structures

Following structures from one producer were chosen for these investigations:

- PCE-1: short side chain, high charge density

- PCE-2: short side chain, low charge density

- PCE-3: long side chain, low charge density

- PCE-4: long side chain, active functional group

Concentration of all sample solutions was 30 %


Saturating point of 4 PCEs for CEM I 42.5 R SÄTTIGUNGSKURVEN für EHZ (CEM I 42,5)

0

10

20

30

40

50

60

70

80

90

100

110

120

0

0,1

0,1

5

0,2

0,2

5

0,3

0,3

5

PCE Konz. [%]

Dre

hm

om

ent

[Nm

m]

EZ_0,4_PCE1

EZ_0,4_PCE2

EZ_0,4_PCE3

EZ 0,4 PCE4

SP

PCE4

PCE1

PCE3

PCE2

SP

PCE Conc. [%]

To

rqu

e [

Nm

m]


Changes of the viscosity and yield stress of CEM I 42,5 R for 4 PCEs Versuchsreihe mit EHZ mit 0,2% PCE

0

0,05

0,1

0,15

0,2

0,25

0,3

0,35

0,40 10

20

30 40 50 60 70 80 90

100

Fließgrenze [Nmm]

Vis

kosi

tät

[eta

]

EHZ 42,5 R

EHZ 42,5 R PCE1

EHZ 42,5 R PCE2

EHZ 42,5 R PCE3

EHZ 42,5 R PCE4

0,2% PCE

PCE 4PCE 3

PCE 1

PCE 2

Effect: PCE2 > PCE1 = PCE3 (slightly consistency) PCE4 (highly consistency)

yield stress [Nmm]

Pla

stic

vis

c osi

ty [

Pa

s]


Drehmoment

0

20

40

60

80

100

120

140

160

180

200

220

240

260

280

0,0

1

0,8

7

1,7

4

2,6

1

3,4

8

4,3

4

5,2

1

6,0

8

6,9

4

7,8

1

8,6

8

9,5

5

10

,4

11

,3

12

,1 13

13

,9

14

,8

15,

6

16,5

17

,4

18

,2

19,

1

20

20

,8

21

,7

Zeit [Min.]

Dre

hm

om

en

t [N

mm

]

M12/0254_0,4_V3_2305

M12/0254_0,4_V4_2305

M12/0256_0,4_V3_2405

M12/0256_0,4_V4_2405

Influence of the fineness of cement

CEM I 42,5 R – fine

Blaine = 5200

CEM I 42,5 R – rough

Blaine = 3380

Time [min.]

To

rqu

e [

Nm

m]


Versuchsreihe D

0,00

0,05

0,10

0,15

0,20

0,25

0,30

0,35

0,40

0

10

20

30

40

50

60

70

80

90

10

0

11

0

12

0

13

0

14

0

15

0

16

0

Fließgrenze [Nmm]

Vis

ko

sit

ät

[eta

]

CEM I 42,5 R_5200

CEM I 42,5 R_5200 PCE1

CEM I 42,5 R_5200 PCE2

CEM I 42,5 R_5200 PCE3

CEM I 42,5 R_3830

CEM I 42,5 R_3830 PCE1

CEM I 42,5 R_3830 PCE2

CEM I 42,5 R_3830 PCE3

CEM I 42,5 R_3830 PCE4

CEM I 42,5 R_5200 PCE4

yield stress [Nmm]

Pla

stic

vis

c osi

ty [

Pa

s]

Influence of the fineness of cement – Viscosity and yield stress in combination with 4 different PCE

Blaine = 5200

Blaine = 3830

PCEs change the yield stress and viscosity starting from different base level - the effect of PCEs on cement with lower Blaine is definitely stronger

0,2% PCE


20

40

60

80

100

120

140

160

180

200

220

240

260

280

300

0,0

1,0

2,0

3,0

4,0

5,0

6,0

7,0

8,0

9,0

10

,0

11

,0

12

,0

13

,0

14

,0

15

,0

16

,0

17

,0

18

,0

19

,0

20

,0

21

,0

Zeit [Min]

Dre

hm

om

ent

[Nm

m]

Time [min.]

To

rqu

e [

Nm

m]

DH 0,25%, HH 4.36%, AH 0%

DH 1.64%, HH 2.55 %, AH 1.22 %

Effect of sulphate retarding agent

A-Blaine = 5.200

B-Blaine = 5.370


Effect of sulphate retarding agent - viscosity and yield stress in combination with PCEs

Versuchsreihe B

0,00

0,05

0,10

0,15

0,20

0,25

0,30

0,35

0,40

0

10

20

30

40

50

60

70

80

90

10

0

11

0

12

0

13

0

14

0

15

0

16

0

Fließgrenze [Nmm]

Vis

ko

sit

ät

[eta

]

CEM I 42,5 R_ACEM I 42,5 R_A PCE1CEM I 42,5 R_A PCE2CEM I 42,5 R_A PCE3CEM I 42,5 R_BCEM I 42,5 R_B PCE1CEM I 42,5 R_B PCE2CEM I 42,5 R_B PCE3CEM I 42,5 R_A PCE4CEM I 42,5 R_B PCE4

A = DH 0,25%, HH 4.36%, AH 0%

B = DH 1.64%, HH 2.55 %, AH 1.22 %

Adding AH changes obviously the initial values.By adding PCE the values change as expected. The different effect of PCE4 is unique.

yield stress [Nmm]

Pla

stic

vis

c osi

ty [

Pa

s]

0,2% PCE


Effect of summer – winter temperature on PCE1SÄTTIGUNGSKURVEN

0

20

40

60

80

100

120

140

0 0,1 0,15 0,2 0,25 0,3 0,35PCE1 Konz. [%]

Dre

hm

om

ent

[Nm

m]

EZ_0,4_PCE1_SOM

EZ_0,4_PCE1_WIN

EZ_0,4_PCE1

Winter (10 °C)

20 °C

Summer (35 °C)

PCE1 con. [%]

higher temperature in summer lower conc. of PCE 1

To

rqu

e [

Nm

m]


SÄTTIGUNGSKURVEN

0

20

40

60

80

100

120

140

160

0,00 0,10 0,15 0,20 0,25 0,30 0,35

EZ_0,4_PCE2_SOM

EZ_0,4_PCE2_WIN

EZ_0,4_PCE2

Fließmittelgehalt

Dre

hm

om

ent

[Nm

m]

Winter (10 °C)

20 °C

Sommer (35 °C)

No effect of temperature for PCE2

Effect of summer – winter temperature on PCE2


ConclusionsManufacturer's expectations to current test results:

- PCE-1: short side chain, high charge density. In the mortar/concrete: moderate (good) fluidizer, good consistency, slightly retardant could be confirmed

- PCE-2: short side chain, low charge density. In the mortar/concrete: good (very good) fluidizer, moderate (lightly) consistency, slightly retardant could be confirmed to some extent

- PCE-3: long side chain, low charge density. In the mortar/concrete: very good fluidizer (good) , slightly consistency, no retardant could be confirmed to some extent (similar to PCE1)

- PCE-4: long side chain, active functional group. In the mortar/concrete: slight fluidizer, very good consistency could be confirmed


In addition to the well known factors such as limestone and blastfurnance slags content, fineness, sulphate retarding agent and temperature affect the efficiencies of the PCE-Superplasticizers.

Rheological investigations are necessary for selection of plasticizer for the best performance (fluidity and stability)

In principle the effect of two or more factors of cement paste can be estimated by these investigations the combined effect

Prospects: transfer of the results on cement paste to mortar and concrete

Summary of Rheological investigations on cement paste


Thank you for your kind attention!

[email protected]@smartminerals.at

www.smartminerals.atwww.smartminerals.at

impact of some parameters in cement production on ... o is mainly determined by dynamic ... setting...

Documents