The Benefits of Rheology Enhancing Admixtures on High ...€¦ · 04/06/2016 · Concrete rheology...
Transcript of The Benefits of Rheology Enhancing Admixtures on High ...€¦ · 04/06/2016 · Concrete rheology...
The Benefits of Rheology Enhancing Admixtures on High Performance Concrete
Dr. Bruce J. Christensen
Vice President, Global Technology & Innovation Management
BASF Construction Chemicals Division
HKCI Annual Concrete Seminar
Hong Kong
6 December 2017 v1
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Global Megatrends Population Growth and Urbanization
-
1.00
2.00
3.00
4.00
5.00
6.00
7.00
8.00
9.00
10.00
1000 1100 1200 1300 1400 1500 1600 1700 1800 1900 2000 2100
Wo
rld
Po
pu
lati
on
(b
illio
ns
)
1 billion in 1804
2 billion in 1927
4 billion in 1973
6 billion in 1999
6.8 billion in 2010
9.2 billion in 2050
>60% by
2050
Source: United Nations Population Facts: Aug 2014
3
Consequences of Global Megatrends Demand for Resources
The future world
population
creates a higher
demand for:
for construction
and buildings
for food for energy for land for water
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Consequences on Construction Easy & Fast Construction, Green Buildings, …
Systems
Energy Efficiency
Fast & Easy Construction
Design & Style
Green Building
Comfort & Health
5
Drivers
CO2 reduction
Utilize available materials
Total cost reduction
Action
Replacement of OPC by Slag/Fly ash Nat. Pozzolans Fillers / Dust
Use of poorer quality aggregates
Challenges
1. Stickiness
2. Pumpability
3. Long mixing
4. Poor finish
Solution
Mix design optimization
Advanced concrete admixtures
Consequences on Concrete Achieve adequate Performance with “Poorer” Materials
Rheology Enhancing Admixtures
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Kg/m3 1,4% Standard PCE 1,5% REA type
CEM I 52,5N 350 350
Filler (limestone) 150 150
G/S 1 1
total water 195 195
Water/Binder ratio 0,55 0,55
C35 design, 700 mm initial slump flow
1. Stickiness Reduction Faster T500 Times
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1. Stickiness Reduction Shorter V Funnel Times
8
Identical mix designs
Identical initial slump flows
Standard PCE Concrete
6 seconds 22 seconds
1. Stickiness Reduction Shorter L Box Times
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2. Improved Pumpability Rheology characterized by Yield Stress and Viscosity
Intrinsic characteristics
t0 : yield point; minimum shear
stress to initiate the flow
η : plastic viscosity; slope of the
shear stress curve vs. shear rate
t : shear stress
𝛄 : shear rate
t0 h
t
Quantified by
measurements
using a concrete
rheometer
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2. Improved Pumpability Concrete Viscosity reduced vs Conventional Admixtures (1/2)
Slump: S4
W/C 0,45
111
77
129
80
0
20
40
60
80
100
120
140
Standard plasiciser MasterGlenium SKY 3500
Pla
sti
c v
isco
sit
y
[P
a *
s]
T90
T0 T90
T0
Standard plasticizer Rheology Enhancing
Lower viscosity maintained even after 90 minutes
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2. Improved Pumpability Concrete Viscosity reduced vs Conventional Admixtures (2/2)
0
20
40
60
80
100
120
140
160
180
200
0 2
Vis
co
sit
y (
cp
s)
Time since Mixing (hours)
Water Reducer 1(1.75%)
Conventional(1.25%)
Rheology Enhancing(1.25%)
0
10
20
30
40
50
60
70
80
1 7
Co
mp
res
siv
e S
tre
ng
th (
Mp
a)
Time since Mixing (days)
Water Reducer 1(1.75%)
Conventional(1.25%)
Rheology Enhancing(1.25%)
Viscosity increased only slightly after 120 minutes and without
impact on setting and early strength development
20 oC
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2. Improved Pumpability Field Example with high Additions
Grade Cement
(OPC 53) Fly Ash GGBS M. Silica w/b Free water 20 mm 10 mm
Crushed
sand
M80 480 130 45 50 0.21 148 550 430 745
Pumping Pressure 60 Bar
Nos of Strokes 5 Strokes/Min
Cylinder Filling 12%
Pump Output 3.5 m3/hr
Plant Output 5.0 m3/hr REA Tu[e-
160 Bar Standard PCE
- 220 Bar
Standard PCE
REA type
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3. Faster Mixing Times Rheology Enhancing Admixture wets out faster
Rheology Enhancing Admixture – 92 Sec
Standard PCE - 145 Sec
Benefits
Potential to increase
productivity of batching plant
Less wear & tear on mixers
Lower energy consumption
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4. Better Finishes Benefits in both Plastic and Hardened State
Easier smoothening of surface
Better response to vibration
Helpful for large elements
Easier filling of complex formwork
Less defects in concrete appearance
Very good dispersing effects on SCM
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4. Better Finishes Particularly with high Carbon Content Flyash
Standard PCE Rheology Enhancing
Very good dispersing effects
Uniform finishes
Example of fluctuations in surface
finish with fly ash containing high
contamination with free carbon
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Project Reference 1 Signature Tower, Tun Razak Exchange, Kuala Lumpur, MY (opens in 2018)
Challenges:
Single continuous pour for raft
Concrete rheology & pumpability
at low w/c ratio
>2hrs workability retention
Achievements:
19,400m3 of concrete poured in 60hrs
Largest continuous pour in Malaysia
Enhanced concrete rheology
Improved batching plant productivity
Made possible with MasterEase
Raft & superstructure for 1,438ft skyscraper
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Project Reference 2 Commercial Building, New Delhi, India
Challenges:
C45 concrete
Target flow of 650 mm
Pipe diameter: 125 mm
Pipe length: 60 m (Horizontal) + two 90°
bends + 90 m (Vertical)
Achievements:
Reduced pump pressure by >15%
Friction factor reduced from 4.7 to 3.9
Faster discharge and placement
Conventional PCE – 130 bar
MasterEase – 110 bar
Contractor: Shapoorji Pallonji
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Project Reference 3 Four Seasons Hotel, Bangkok, Thailand (opens in 2018)
Challenges:
C60 and C80 concrete
Pump height: 305 m
Achievements:
Reduced pump pressure by >25%
Conventional PCE mix: 200 bar
MasterEase mix: 140 bar
Location: Water front
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Project Reference 4 Pumping Trial, Vienna, Austria
Typical PCE
Plastic Viscosity (Pa-s) Pump Pressure (bar)
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Reduces the initial and later stage viscosity of
concrete mixtures, as compared to conventional
admixture solutions
Resulting pump pressures and mixing times are
reduced vs conventional solutions
Benefits
Faster placement
Higher usage of poorer materials
Less wear and energy use
Easier finishing of surfaces
Good distribution of SCM’s (FA)
Better surface aesthetics
Summary Rheology Enhancing Admixtures have many benefits
electrostatic repulsion
spatial repulsion
150 years
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