Post on 29-Mar-2020
El ensayo de doble punzonamiento con cuña para la caracterizaciòn del comportamiento a tracciòn del HRF Liberato Ferrara Politecnico di Milano, Italy
EXPERIENCIAS INTERNACIONALES DEL HORMIGON REFORZADO CO FIBRAS
Barcelona, 21 de marzo de 2013
FR(SC)C: an intelligent material
shear-flow induced fiber orientation
Netwonian fluid
free surface flowvelocity/drag force
profileresultant drag force
on flow-through fibers:
fiber orientation effect
MOULD
high yield stress fluid
free surface flow
(e.g. FRC casting)per
per
velocity/drag force
profile (extended plug flow)resultant drag force
on flow-through fibers:
fiber drag effect
MOULD
low yield stress/low viscosity
fluid free surface flow
(e.g. FRSCC casting)per
per
velocity/drag force profile
(limited plug flow - low gradient)resultant drag force
on flow-through fibers:
limited fiber orientation effect
MOULD
low yield stress-high viscosity
fluid free surface flow
(e.g. FRSCC casting)per
per
velocity/drag force profile
(limited plug flow - high gradient)resultant drag force
on flow-through fibers:
fiber orientation effect
MOULD
Fibers can be aligned along the direction of the casting flow
Identification of material properties as a function of flow induced fiber alignment: which test?
Direct tension tests?
Not easy to be properly performed
Bending tests?
Need for back analysis
Identification of material properties as a function of flow induced fiber alignment: which test?
3 Point Bending Test … … Wedge Splitting Test
Identification of material properties as a function of flow induced fiber alignment: which test?
Direct Tension Test
(rotating platens)
di Prisco et al., Materials and Structures, 2013
Identification of material properties as a function of flow induced fiber alignment: Double Edge Wedge Splitting test
Identification of material properties as a function of flow induced fiber alignment: Double Edge Wedge Splitting test
di Prisco et al., Materials and Structures, 2013
di Prisco et al., Materials and Structures, 2013
0 4 8 12 16 20
applied vertical load P (kN)
0
4
8
12
16
20
mea
sure
d t
rans
vers
e lo
ad F
SP (k
N)
y = 0.89 x
Identification of material properties as a function of flow induced fiber alignment: Double Edge Wedge Splitting test
friction effects
Ferrara et al., Materials and Structures, 2011
Identification of material properties as a function of flow induced fiber alignment: Double Edge Wedge Splitting test
calibration
Constituent Quantity (kg/m3)
Cement 600
Slag 500
Sand 0-2 mm 982
Water 200
Superplasticizer 33 (lt/m3)
Steel fibers (lf = 13 mm; df = 0.16 mm) 100
Ferrara et al., Materials and Structures, 2011
Identification of material properties as a function of flow induced fiber alignment: Double Edge Wedge Splitting test
calibration
Slump flow V-funnel L-box U-box J-ring
Ferrara et al., Materials and Structures, 2012
Identification of material properties as a function of flow induced fiber alignment: Double Edge Wedge Splitting test
calibration: achieving fiber orientation
slab casting
flow induced
fiber alignment
slab cutting
DEWS testing
?
Magnetic inductance associated to the flux
LV = LV0 + Lfibers
Matrix contribution LV0
Fiber contribution Lfibers
Assess local concentration and orientation of fibers
Identification of material properties as a function of flow induced fiber alignment: Double Edge Wedge Splitting test
calibration: monitoring (ND) fiber orientation
Magnetic method
Ferrara et al., Materials and Structures, 2012
Identification of material properties as a function of flow induced fiber alignment: Double Edge Wedge Splitting test
calibration: monitoring (ND) fiber orientation
Magnetic method
Ferrara et al., Materials and Structures, 2012
Faifer et al., Sensors, 2013
preferential fiber
alignment
perform M measurements
rotate by 2 /m at once
Directions of maximum inductance
Self compactability – flow induced fiber alignment
0 50 100
nominal fiber content (kg/m3)
0
5
10
15
20
25
Lav
era
ge (
H)
y = 0.18 x (R2 = 0.988)
average of Laverage
Calibration
Quantitative assessment of local unhomogeneities in fiber
dispersion
Ferrara et al., Materials and Structures, 2012
Identification of material properties as a function of flow induced fiber alignment: Double Edge Wedge Splitting test
calibration: monitoring (ND) fiber orientation
Magnetic method
preferential fiber
alignment
perform M measurements
rotate by 2 /m at once
Identification of material properties as a function of flow induced fiber alignment: Double Edge Wedge Splitting test
calibration: monitoring (ND) fiber orientation
Magnetic method
Ferrara et al., Materials and Structures, 2012
Faifer et al., Sensors, 2013
1
2
3
4
5
6
7
8
9
10
11
12
13
15
16
17
18
ND = 110.5
ND = 101.8D = 119.1
14
ND = 100.8 ND = 111.7
ND = 108.7D = 109.5
ND = 110.5
ND = 103.5D = 107.8
ND = 100D = 101.9
ND = 106.6D = 109.9
ND = 103.6D = 106.7
ND = 105.7D = 105.6
ND = 99.5D = 99.4
ND = 93.7D = 98.2
ND = 79.4D = 85
ND = 94.2
ND = 97.5 ND = 88.7
ND = 75.9
Ferrara et al., Materials and Structures, 2012
Identification of material properties as a function of flow induced fiber alignment: Double Edge Wedge Splitting test
calibration
slab casting
flow induced
fiber alignment
slab cutting
DEWS testing
Ferrara et al., Materials and Structures, 2012
Identification of material properties as a function of flow induced fiber alignment: Double Edge Wedge Splitting test
calibration
0 1 2 3 4 5
COD (mm)
0
2
4
6
8
10
N (
N/m
m2)
unfavorable flow-induced fiber alignment
favorable flow-induced fiber alignment
H2
H1
S
The same material exhibits either a
strain hardening
Or
strain softening
tensile behaviour
whether tested parallel or orthogonal to flow induced
fiber alignment
di Prisco et al., Materials and Structures, 2013
Identification of material properties as a function of flow induced fiber alignment: Double Edge Wedge Splitting test
calibration
0 1 2 3 4 5
COD (mm)
0
2
4
6
8
10
N (
N/m
m2)
unfavorable flow-induced fiber alignment
favorable flow-induced fiber alignment
H2
H1
S
Multiple cracking
Ferrara et al., Materials and Structures, 2012
Identification of material properties as a function of flow induced fiber alignment: Double Edge Wedge Splitting test
a proposal: strain softening material
st
ress
strain = COD/helement
plain matrix(as from MC2010)
0.5/hel 2.5/hel
fFT ,2 .5
fFt
0.9fFt
0.015%
fFT,0.5
Ferrara et al., Materials and Structures, 2012
Identification of material properties as a function of flow induced fiber alignment: Double Edge Wedge Splitting test
a proposal: strain hardening material
stre
ss
strain = peak +(COD-CODpeak)/helement
peak + 0.5/hel
0.9fFt
fFT ,peak
fFT , peak+0.5
CODpeak
LCOD
peak + 2.5/hel
strain = COD/LCOD
peak =
fFT, peak+2.5
Same opening of the localized crack as for
strain softening
di Prisco et al., Materials and Structures, 2013
Identification of material properties as a function of flow induced fiber alignment: Double Edge Wedge Splitting test
finite element validation
Crush-Crack damage model
di Prisco et al., Materials and Structures, 2013
Identification of material properties as a function of flow induced fiber alignment: Double Edge Wedge Splitting test
finite element validation and mesh independence
0 1 2 3 4
COD (mm)
0
2
4
6
8
10
(M
Pa)
exp.
num.
H2
H1
S
0 1 2 3 4
COD (mm)
0
2
4
6
8
10
(M
Pa)
experimental
num - hel = 2.67 mm
num - hel = 2.0 mm
num - hel = 1.33 mm
di Prisco et al., Materials and Structures, 2013
Identification of material properties as a function of flow induced fiber alignment: Double Edge Wedge Splitting test
finite element validation: uncoupling of principal stresses
CODcracking COD = 0.5 mm CODpeak = 0.75 mm
CODpeak + 0.25 mm
CODpeak + 1.25 mm
COD = 4 mm
Principal compressive stresses follow same “softening trend as tensile (unlikely in
Brazilian test)
di Prisco et al., Materials and Structures, 2013
Identification of material properties as a function of flow induced fiber alignment: Double Edge Wedge Splitting test
finite element validation: uncoupling of principal stresses
-2 0 20
20
40
60
80
100
liga
men
t(c
oord
inat
e in
mm
)
0 2 4 6 8 10
principal stresses (MPa)
CODcracking = 0.05 mm
COD = 0.5 mm
CODpeak = 0.75 mm
CODpeak + 0.25 mm = 1 mm
CODpeak +1.25 mm = 2.0 mm
COD = 4mm (e.o.c.)
compressive tensile
Strain hardening material
di Prisco et al., Materials and Structures, 2013
Identification of material properties as a function of flow induced fiber alignment: Double Edge Wedge Splitting test
finite element validation: uncoupling of principal stresses
-1 0 10
20
40
60
80
100
liga
men
t(c
oord
inat
e in
mm
)
0 1 2 3 4
principal stresses (MPa)
CODcracking = 0.03 mm
COD = 0.05 mm
COD = 0.25 mm
COD = 1.25 mm
COD = 2.0 mm
COD = 3.1 mm (e.o.c.)
compressive tensile
Strain softening material
di Prisco et al., Materials and Structures, 2013
Identification of material properties as a function of flow induced fiber alignment: Double Edge Wedge Splitting test
finite element validation: principal strain evolution
Strain hardening material
0 10 20
x (mm)
1
2
CODcracking = 0.05 mm
COD = 0.5 mm
CODpeak = 0.75 mm
CODpeak + 0.5 mm
CODpeak + 2.5 mm
COD = 4.0 mm (e.o.c.)
0 10 20
x (mm)
0
1
2
-20 -10 00
0.1
0.2
0.3
-20 -10 00
0.01
0.02
0.03
pre-peak zoom
pre-peak zoom
di Prisco et al., Materials and Structures, 2013
Identification of material properties as a function of flow induced fiber alignment: Double Edge Wedge Splitting test
finite element validation: principal strain evolution
Strain hardening material
0
20
40
60
80
100
liga
men
t(c
oord
inat
e in
mm
)
0 0.4 0.8 1.2 1.6 2
CODcracking = 0.05 mm
COD = 0.5 mm
CODpeak = 0.75 mm
CODpeak + 0.5 mm = 1.25 mm
CODpeak +2.5 mm = 3.25 mm
COD = 4 mm (e.o.c.)
di Prisco et al., Materials and Structures, 2013
Identification of material properties as a function of flow induced fiber alignment: Double Edge Wedge Splitting test
finite element validation: principal strain evolution
Strain softening material
0 10 20
x (mm)
0.5
1
CODcracking = peak = 0.03 mm
COD = 0.05 mm
COD = 0.5 mm
COD = 1.5 mm
COD = 2.5 mm
COD = 3.1 mm (e.o.c.)
0 10 20
x (mm)
0
0.1
0.2
-20 -10 00
0.2
0.4
-20 -10 00
0.001
0.002
pre-peak zoom
pre-peak zoom
di Prisco et al., Materials and Structures, 2013
Identification of material properties as a function of flow induced fiber alignment: Double Edge Wedge Splitting test
finite element validation: principal strain evolution
Strain softening material
0
20
40
60
80
100
ligam
ent
(coo
rdin
ate
in m
m)
0 1 2 3 4 5
CODcracking=peak = 0.03 mm
COD = 0.05 mm
COD = 0.5 mm
COD = 1.5 mm
COD = 2.5 mm
COD = 3.1 mm (e.o.c.)
di Prisco et al., Materials and Structures, 2013
Identification of material properties as a function of flow induced fiber alignment: Double Edge Wedge Splitting test
finite element validation: damage evolution
CODcracking = 0.05 mm
Strain hardening materials
COD = 0.5 mm
CODpeak = 0.75 mm
CODpeak + 0.5 mm
CODpeak + 1.25 mm
CODpeak + 3.25 mm
di Prisco et al., Materials and Structures, 2013
Identification of material properties as a function of flow induced fiber alignment: Double Edge Wedge Splitting test
finite element validation: uncoupling of principal stresses
CODcracking = 0.03 mm
Strain softening materials
CODcracking = 0.05 mm
CODcracking = 0.5 mm
CODcracking = 1.5 mm
CODcracking = 2.5 mm
CODcracking = 3.1 mm
0 2 4 6 8 10
COD (mm)
0
10
20
30
N (
N/m
m2)
beam L1
beam L2
beam T2
beam T1
Ferrara et al., Materials and Structures, 2011
500 mm - 20 in.
150 mm - 6 in.
450 mm - 18 in.
200 mm - 8 in.
A
A sect. A-A
150 mm
6 in.
30 mm - 1.2 in7 mm
Identification of material properties as a function of flow induced fiber alignment: 4-point bending tests
b
eam
T2
beam
T1
50 150150150 500
beam L2
beam L1
150
150
150
50
casting
direction
supposed flow lines
T1-BT2-B
T1-AT2-A L1-A
L2-AL2-B
L1-B
Slab A
COD
Str
ess
wI
0.1 mm
fIf
N,peak
wpeak
w1
w2
wi
localized crackmultiple cracking
w1 = (3-5 wI – wpeak h/lCOD) + wpeak
w2 = (0.02h 20% – wpeak h/lCOD) + wpeak
wi = ( h 20% – wpeak h/lCOD) + wpeak
h specimen depth (30 mm)
lCOD COD measurement length
(200 mm)
Ferrara et al., Materials and Structures, 2011
Identification of material properties as a function of flow induced fiber alignment: 4-point bending tests
0.9 fIf/
N,peak/ 1
peak = CMODpeak
lCOD
arctg Ec
25+2h0.7
2h0.7
Ec = 22000 (fc/10)0.3 = 43600 N/mm2
for fc = 96 N/mm2
= 2.16 (for h = 30 mm)
M = N,peak bh2/6
peakpeak
0.9fIf/
xx
crack opening w
N, peak
0.02 h
1 feq,2
2 feq, wu
wu = 0.10 h
0.10
M = feq (0.1h) bh2/6(0.02)
peak
Compression
force0.02
(0.10)
1
M = feq2 bh2/6
(0.02)0.02
peak
x x
Ferrara et al., Materials and Structures, 2011
Identification of material properties as a function of flow induced fiber alignment: 4-point bending tests
0 2 4 6
COD (mm)
0
2
4
6
8
10
(N
/mm
2)
DEWS L1/2-B
DEWS T1/T2-B
DEWS T1/T2-A
DEWS L1/L2-A
Slab A
beam
T2
beam
T1
50 150150150 500
beam L2
beam L1
150
150
150
50
casting
direction
supposed flow lines
T1-BT2-B
T1-AT2-A L1-A
L2-AL2-B
L1-B
Slab A
Identification of material properties as a function of flow induced fiber alignment: DEWS tests
di Prisco et al., Materials and Structures, 2013
di Prisco et al., Materials and Structures, 2013
Identification of material properties as a function of flow induced fiber alignment: Double Edge Wedge Splitting test
in plane rotations
0 5 10 15 20
in plane rotation - front (°)
0
0.5
1
P/P m
ax
Slab ADEWS L1-B
DEWS T1-B
DEWS L1-A
DEWS T1-A
top-center
top-bottom
0 5 10 15 20
in plane rotation - rear (°)
0
0.5
1
P/P m
ax
Slab ADEWS L1-B
DEWS T1-B
DEWS L1-A
DEWS T1-A
top-center
top-bottom
di Prisco et al., Materials and Structures, 2013
Identification of material properties as a function of flow induced fiber alignment: Double Edge Wedge Splitting test
Out of plane rotations
0 1 2 3 4
out of plane rotation - bottom (°)
0
0.5
1
P/P m
ax
Slab ADEWS L1-B
DEWS T1-B
DEWS L1-A
DEWS T1-A
0 1 2 3 4
out of plane rotation - mid (°)
0
0.5
1
P/P m
ax
Slab ADEWS L1-B
DEWS T1-B
DEWS L1-A
DEWS T1-A
0 1 2 3 4
out of plane rotation - top (°)
0
0.5
1
P/P m
ax
Slab ADEWS L1-B
DEWS T1-B
DEWS L1-A
DEWS T1-A
0 0.002 0.004 0.006 0.008 0.01
strain
0
4
8
12
16
(N/m
m2)
beams L1/2
slab A
arctg Ec
DEWS L1/2-B
DEWS T1/2-B
0.6 3
crack opening w (mm)
0
4
8
12
16
(N/m
m2)
0 3 6 9
beams L1/2
slab A
DEWS L1/2-B
DEWS T1/2-B
Identification of material properties as a function of flow induced fiber alignment: 4pb vs. DEWS tests
di Prisco et al., Materials and Structures, 2013
0.2 0.4 0.6 0.8orientation density
(vertical to the fracture surface)
0
5
10
15
4pb (
N/m
m2)
peak = 0.25 + 21.6x (R2 = 0.937)
0.02h = 1.94 + 6.4x (R2 = 0.785)
0.10h = 1.37 + 3.0x (R2 = 0.940)
0.2 0.4 0.6 0.8orientation density
(vertical to the fracture surface)
0
5
10
15
DE
WS (
N/m
m2)
peak = 0.6 + 11.7x (R2 = 0.745)
0.01h = 0.4 + 10.4x (R2 = 0.805)
0.05h = 0.8 + 3.0x (R2 = 0.745)
Identification of material properties as a function of flow induced fiber alignment: 4pb vs. DEWS tests
di Prisco et al., Materials and Structures, 2013
Concluding remarks
Double Edge Wedge Splitting test suitable to identify, with no need for back analysis, the tensile cosntitutive
behaviour of FRCs performing and indirect test
Compact specimen geometry and dimensions: suitable for identifying fiber orientation dependant behaviour
Test methodology has been demonstrated capable to discriminate between strain softening and hardening
materials
size effect …?
Thank you for your attention!
Fiber dispersion and orientation
Hardened state behaviour Fresh state behaviour
Understanding the performance: from material to
structure
Fiber dispersion and orientation
Hardened state behaviour Fresh state behaviour
Modelling the performance: from material to
structure
fibres
velocity profile drag forces orientating effect
fibres
velocity profile drag forces orientating effect
fibres
velocity profile drag forces orientating effect
Tailoring the performance: from material to
structure
B
A
Lc
vLL
lwsR
iw
0 10 20 30
curvature (1/mm*105)
0
1
2
3
4
Mom
ent
(kN
m)
0 200 400 600
curvature (1/in) *105
0
2
4
Mom
ent (ft kips)
Mu,exp = 2.2 kNm = 3 ft kips
Mcr,exp = 1.7 kNm = 2.3 ft kips
= 0.23
orientation density
= 0.35
= 0.55
= 0.63
dashed line - CNR-DT204
solid line - proposed approach
experiments
rheology
fiber monitoring
casting and processing
1 kN m moment at mid span
1 kN/m distributed load