The Rheological Characteristics of SFRSCC with PFA and GGBS CONCRETE RHEOLOGY CONCRETE WORKABILITY CORRELATION
Aug 06, 2015
The Rheological Characteristics of SFRSCC with PFA and GGBS
CONCRETE RHEOLOGY
CONCRETE WORKABILITY
CORRELATION
Objectives
Mix Design and Modelling
Hershel-Bulkley model
Rheological and Empirical Parameters
Statistics
Workability retention
GGBS and PFA
Rheology and Workability
Influence of steel fibres
Influence of time
0 1 2 3 4 5 6 7 80
2
4
6
8
10
12
Speed (rev/s)
Tor
que
(N/m
)
Slope = h
T = To + ANb
g
Linear approximation of Hershel-Bulkley model
0 1 2 3 4 5 6 7 80
2
4
6
8
10
12
Shear strain rate, γ
Shea
r str
ess,
τ
Slope = µ
τ = τo + Kγn
τo
Linear approximation of Hershel-Bulkley model
Mix Design and Testing Sequence
REF REF REF
ComponentSeries 1 (kg/m3)
Series 2 (kg/m3)
Series 3 (kg/m3)
CEM II/A-L 580 406 290Limestone filler 20 20 20GGBS - - 290PFA - 174 -Fine aggregate 1020 1020 1020Coarse aggregate 630 630 630Superplasticiser (Glenium 27) 12.5 12.5 12.5Stabiliser (RheoMatrix 100) 78 78 78Water 215.5 215.5 215.5
Steel fibre type
Steel fibre content
SCC-Series 1 (R 65/35)
SCC-Series 2 (R 65/35)
SCC-Series 3 (R 65/35)
0 (kg/m3) (REF) o o o5 (kg/m3) o o o10 (kg/m3) o o o15 (kg/m3) o o o20 (kg/m3) o o o25 (kg/m3) o o o30 (kg/m3) o o o
SequenceRegime-1 (15 min after addition of
water)
Regime-2 (30 - 65 min after addition
of water)
Regime-3 (65 - 95 min after addition
of water)1 TWT TWT TWT2 Slump flow Slump flow Slump flow3 L-box L-box L-box4 J-ring J-ring J-ring
Hershel-Bulkley Curve Fitting
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 1.1 1.2 1.3
0
1
2
3
4
5
6R² = 0R² = 0R² = 0
SCC-1, 15 min
Polynomial (SCC-1, 15 min)
SCC-1, 45 min
Polynomial (SCC-1, 45 min)
SCC-1, 75 min
Polynomial (SCC-1, 75 min)
Hershel-Bulkley, 15 min
Hershel-Bulkley, 45 min
Hershel-Bulkley, 75 min
Speed (rev/s)
Tor
que
(N/m
)
Effect of PFA and GGBS on Rheology and workability
0 5 10 15 20 25 300
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
1.8
2
SFRSCC
SFRSCC with PFA
SFRSCC with GGBS
Steel fibre content (kg/m3)
Rheolo
gic
al para
mete
r, g
0 5 10 15 20 25 300
1
2
3
4
5
6
7
SFRSCC
SFRSCC with PFA
SFRSCC with GGBS
Steel fibre content (kg/m3)
Rheolo
gic
al para
mete
r, h
0 5 10 15 20 25 300
10
20
30
40
50
60
70
80
SFRSCCSFRSCC with 30% PFASFRSCC with 50% GGBS
Steel fibre content (kg/m3)
7-D
ay s
trength
(N
/mm
)
STD: 1.3
STD: 1.08STD: 1.5
Empirical and Rheological Parameters
0 10 20 30 40 50 60 700
0.2
0.4
0.6
0.8
1
1.2
f(x) = − 0.0290657251388758 x + 1.09101341644886R² = 0.829717455591301
SCC-1 to SCC-21, 15 min
SCC-1 to SCC-21, 30 - 65 min
J-ring, step of blocking (mm)
L-b
ox b
lock
ing
ratio
(H
2/H
1)
CV = -2.132
0 0.5 1 1.5 2 2.5 3 3.5500
550
600
650
700
750
800
f(x) = − 35.4682188203232 x + 734.669158742188R² = 0.21517400976868
SCC-1 to SCC-20, 15 min
Linear (SCC-1 to SCC-20, 15 min)
Rheological parameter, g
Slu
mp
flow
spr
ead
(mm
)
CV = -9.98
2 2.5 3 3.5 4 4.5 5 5.5 6 6.5 70
2
4
6
8
10
12
f(x) = 0.614155144502876 x + 0.836509601156264R² = 0.30281072967086
SCC-1 to SCC-20, 15 min
Linear (SCC-1 to SCC-20, 15 min)
Rheological parameter, h
Slu
mp
flow
, t50
0 tim
e (s
ec)
CV = 1.0
Empirical and Rheological parameters
0 5 10 15 20 25 30 350
0.2
0.4
0.6
0.8
1
1.2
f(x) = − 0.0272018128551079 x + 1.0984591157247R² = 0.899463415391305
J-ring, step of blocking (mm)
L-b
ox b
lock
ing
ratio
(H
2/H
1)
CV = -1.043
0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0600
620
640
660
680
700
720
740
SCC-14
SCC-21
f(x) = − 43.0242709698268 x + 730.885232433187R² = 0.796421966228956
Rheological parameter, g
Slu
mp-
flow
spr
ead
valu
e (m
m)
CV = -4.571
1.5 2 2.5 3 3.5 4 4.50
1
2
3
4
5
6
7
SCC-14
SCC-21f(x) = 1.62751162621118 x − 0.679462981188106R² = 0.834719873080687
Slump-flow, t500 time (sec)R
heol
ogic
al p
aram
eter
, h
CV = 0.7172
Conclusions and Recommendations
The rheological parameter g and h increase with an increase in SF content
Correlation between rheology and workability
Good correlation between L-box and J-ring (inversely related)
Good correlation between inverted slump flow and g (inversely related)
Good correlation between t500 time and h (positively related)
Poor correlation between rheology and workability, 15 to 95 min.
PFA and GGBS
Reduction in g and an increase in h
Retained workability
Recommendations
Record idle pressures immediately after each test
Weld steel ribs to inside of TWT bowl
Modified Bingham model
Fabricate a coaxial impeller arrangement for the TWT
Torque calibration
Expressing the parameters g and h into fundamental units
Better control of the aggregates to evaluate the feasible use of SF
Evaluate passing ability with J-ring