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

2

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

4

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

6

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

7

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

9

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

10

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

11

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

12

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

13

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

14

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

15

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

16

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

17

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

18

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

19

Project Reference 4 Pumping Trial, Vienna, Austria

Typical PCE

Plastic Viscosity (Pa-s) Pump Pressure (bar)

20

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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