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The rheology of control flow concreteG.T. Harris, E. Burns, K.-A. Rieder,J. Curto, N. Tregger
22018 Fall ACI Convention – Sustainable and Low-Cementitious-Materials-Content SCC
ACI 237R-07: Self-consolidating concrete
“…highly flowable, nonsegregating concrete that can spread into place, fill the formwork, and encapsulate the reinforcement without any mechanical consolidation.
In general, SCC is concrete made with conventional concrete materials and, in some cases, with a viscosity-modifying admixture.”
32018 Fall ACI Convention – Sustainable and Low-Cementitious-Materials-Content SCC
Mix proportioning
Conventional concrete
Self-consolidating concrete
• Mix proportioning is complicated
• High cementitious factor
• Significant cost increase
• Difficult to finish
• Increased shrinkage
• Difficult to produce
• Limited applications
To mitigate risk, you need an increase in both expertise/experience as well as material costs
4
Challenges in producing ready-mix SCC
2018 Fall ACI Convention – Sustainable and Low-Cementitious-Materials-Content SCC
• Typical mix proportioning
• Strength: 3500-6500 psi [25-45 MPa]
• Lower cementitious content
• Superior moisture tolerance
• Higher segregation resistance
• Easier finishability
5
What if we could have best of both worlds?
• Slump flows 16-25” [400 to 635 mm]
• Minimal vibration
• Excellent flowability retention for more than 1 hour
• Fast pumping, rapid placement
2018 Fall ACI Convention – Sustainable and Low-Cementitious-Materials-Content SCC
62018 Fall ACI Convention – Sustainable and Low-Cementitious-Materials-Content SCC
Novel admixture formulationC
on
cre
te v
alu
e [
$/y
d3]
Water reduction
MRWR
HRWR
Control flow admix
SCC admix
Conventional
Concrete
Self Consolidating
Concrete
Control Flow
Concrete
Materials Saving
Labor Intensive Labor Saving
Fast Placement
High Materials Cost
QC Intensive• Value
• Robustness
• Materials
• Labor
• Project time
Control flow concrete
▪ Is Conventional Concrete with enhanced flow using novel blend of admixtures
▪ Is not Self Consolidating Concrete with reduced flow
72018 Fall ACI Convention – Sustainable and Low-Cementitious-Materials-Content SCC
Control flow concrete
Conventional concrete
Self-consolidating concrete
Control flow concrete
Slump: 6-8”
Slump flow: 18-22”
Slump flow: 25-30”
82018 Fall ACI Convention – Sustainable and Low-Cementitious-Materials-Content SCC
Control flow concrete
92018 Fall ACI Convention – Sustainable and Low-Cementitious-Materials-Content SCC
Static and dynamic yield stresses
CI June 2007, ACI 238
dynamic yield stress
Static yield stress:
• stress required to initiate flow
• (rest to flow)
Dynamic yield stress:
• stress at which flow stops
• (flow to rest)
102018 Fall ACI Convention – Sustainable and Low-Cementitious-Materials-Content SCC
Static yield stress
2018 Fall ACI Convention – Sustainable and Low-Cementitious-Materials-Content SCC
0
1
2
3
4
5
6
7
8
9
0 5 10 15 20 25
To
rqu
e [N
m]
Time [sec]
Stress growth test
Conventional Concrete
Control Flow Concrete
Self-Consolidating Concrete
112018 Fall ACI Convention – Sustainable and Low-Cementitious-Materials-Content SCC
Flow curve data example
2018 Fall ACI Convention – Sustainable and Low-Cementitious-Materials-Content SCC
0
0.2
0.4
0.6
0.8
1
1.2
1.4
0
0.5
1
1.5
2
2.5
0 200 400 600 800
Spin
dle
speed [R
PS
]
Torq
ue [
Nm
]
Data point [20/sec]
Torque Actual Speed
122018 Fall ACI Convention – Sustainable and Low-Cementitious-Materials-Content SCC
Flow curve results
2018 Fall ACI Convention – Sustainable and Low-Cementitious-Materials-Content SCC
0
1
2
3
4
5
6
7
0 10 20 30
Torq
ue [N
m]
Spindle speed [RPM]
conventional concrete control flow concrete SCC
132018 Fall ACI Convention – Sustainable and Low-Cementitious-Materials-Content SCC
Balancing rheology
0
500
1000
1500
2000
2500
3000
0 20 40 60 80 100
Sta
tic
yie
ld s
tre
ss
[P
a]
Plastic viscosity [Pa.s]
142018 Fall ACI Convention – Sustainable and Low-Cementitious-Materials-Content SCC
Balancing rheology
0
500
1000
1500
2000
2500
3000
0 20 40 60 80 100
Sta
tic
yie
ld s
tre
ss
[P
a]
Plastic viscosity [Pa.s]
152018 Fall ACI Convention – Sustainable and Low-Cementitious-Materials-Content SCC
Balancing rheology
0
500
1000
1500
2000
2500
3000
0 20 40 60 80 100
Sta
tic
yie
ld s
tre
ss
[P
a]
Plastic viscosity [Pa.s]
162018 Fall ACI Convention – Sustainable and Low-Cementitious-Materials-Content SCC
Balancing rheology
0
500
1000
1500
2000
2500
3000
0 20 40 60 80 100
Sta
tic
yie
ld s
tre
ss
[P
a]
Plastic viscosity [Pa.s]
+ Control flow admix
172018 Fall ACI Convention – Sustainable and Low-Cementitious-Materials-Content SCC
Performance comparison example
3500 PSI ready mix
with
HRWR (Conventional)
3500 PSI ready mix
with Control Flow
Admixture
Self Consolidating
Concrete (SCC)
Self-consolidating No Semi-consolidating Yes
Placement Difficult Easy Easy
Labor demand High Low Low
Segregation risk Low Low High
Powder content 500-600 lbs/yd³ 500-600 lbs/yd³ >700 lbs/yd³
Mix design adjustments None None or Minimal (robust to manufactured Sand)
Yes (high quality fine aggregates and
Needs more powder)
Moisture tolerance Tolerant Tolerant Needs very close QC
QC need Routine Routine Extra effort
Drying shrinkage OK OK Higher
Conventional Mix Design with Unconventional Performance
182018 Fall ACI Convention – Sustainable and Low-Cementitious-Materials-Content SCC
Project highlights with control flow concrete
Tanjong Pagar Centre
SingaporeLandmark 81
Ho Chi Minh City, Vietnam
My Home Vihanga Apartments
Hyderabad, India
Mayo Clinic & MD
Anderson Cancer Center
Jacksonville, FL
192018 Fall ACI Convention – Sustainable and Low-Cementitious-Materials-Content SCC
Landmark 81: Ho Chi Minh City
Tallest building in Vietnam
11th Tallest building in the world
GCP’s Dr. Jiang Jiabiao
Final pour, at 400m
202018 Fall ACI Convention – Sustainable and Low-Cementitious-Materials-Content SCC
212018 Fall ACI Convention – Sustainable and Low-Cementitious-Materials-Content SCC
