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1 / 03.03 Smart Minerals GmbHSchneider
Impact of some parameters in cement production on rheological properties of cement paste
Ameneh Schneider Stefan RatzingerAlexander Marcini
2 / 03.03 Smart Minerals GmbHSchneider
Contents
State of the art
Pilot tests and results
Main tests
Results
• Flow diagrams
• Evaluated plastic viscosity - yield stress (Bingham model)
3 / 03.03 Smart Minerals GmbHSchneider
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 +×=
4 / 03.03 Smart Minerals GmbHSchneider
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
6 / 03.03 Smart Minerals GmbHSchneider
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
7 / 03.03 Smart Minerals GmbHSchneider
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
8 / 03.03 Smart Minerals GmbHSchneider
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
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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
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,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
9 / 03.03 Smart Minerals GmbHSchneider
20
40
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320
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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
10 / 03.03 Smart Minerals GmbHSchneider
Drehmoment
0
20
40
60
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100
120
140
160
180
200
220
240
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280
300
0,01
3,0
1
6,01
9,01 1
2
15
18 21 24
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60
63
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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
11 / 03.03 Smart Minerals GmbHSchneider
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
12 / 03.03 Smart Minerals GmbHSchneider
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
13 / 03.03 Smart Minerals GmbHSchneider
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 %
14 / 03.03 Smart Minerals GmbHSchneider
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]
15 / 03.03 Smart Minerals GmbHSchneider
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]
16 / 03.03 Smart Minerals GmbHSchneider
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]
17 / 03.03 Smart Minerals GmbHSchneider
Versuchsreihe D
0,00
0,05
0,10
0,15
0,20
0,25
0,30
0,35
0,40
0
10
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90
10
0
11
0
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0
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0
14
0
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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
18 / 03.03 Smart Minerals GmbHSchneider
20
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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
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,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
19 / 03.03 Smart Minerals GmbHSchneider
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
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10
0
11
0
12
0
13
0
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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
20 / 03.03 Smart Minerals GmbHSchneider
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]
21 / 03.03 Smart Minerals GmbHSchneider
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
22 / 03.03 Smart Minerals GmbHSchneider
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
23 / 03.03 Smart Minerals GmbHSchneider
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
24 / 03.03 Smart Minerals GmbHSchneider
Thank you for your kind attention!
[email protected]@smartminerals.at
www.smartminerals.atwww.smartminerals.at