internal curing in cementitious systems made using saturated lightweight aggregate
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Internal Curing November 17, 2008 Slide 1 of 46
School of Civil EngineeringPurdue University
Internal Curing in Cementitious Systems Made Using Saturated
Lightweight Aggregate
Master’s DefenseRyan Henkensiefken
November 17th, 2008
Internal Curing November 17, 2008 Slide 2 of 46
Introduction
• Lower w/c to reduce drying shrinkage
• Low w/c increased autogenous shrinkage
• RILEM report 41 on internal curing provides laboratory concepts
• Need to move to field applications
Neville (1995)
Internal Curing November 17, 2008 Slide 3 of 46
Objectives
• Define properties of LWA that make it an effective
internal curing agent
• Monitor water movement from LWA to cement
paste
• Examine the fluid absorption characteristics of
mortars
• Measure the unrestrained and restrained
shrinkage in sealed and unsealed conditions
Internal Curing November 17, 2008 Slide 4 of 46
Outline
• Chemical and autogenous shrinkage• Water demand
– Internal void creation and drying fronts• Water supply
– LWA properties, water movement and water distribution• Powers model
– Influence of ‘internal’ water on hydration• Fluid absorption• Role of the pore size on shrinkage• Shrinkage measurements
– Unrestrained and restrained shrinkage in sealed and unsealed conditions
• Conclusions
Internal Curing November 17, 2008 Slide 5 of 46
Chemical Shrinkage
• Chemical Shrinkage– Total volume reduction due to hydration– Hydration product volume is smaller than cement and
water volume
Cement
WaterHydration products
Chemical shrinkage
1 Vol
1 Vol
1.8 Vol
Internal Curing November 17, 2008 Slide 6 of 46
Autogenous Shrinkage
• Autogenous Shrinkage– External volume change in sealed conditions
0 7 14 21 28Age of Specimen (d)
-400
-350
-300
-250
-200
-150
-100
-50
0
Str
ain
(
)
0 7 14 21 28Age of Specimen (d)
-400
-350
-300
-250
-200
-150
-100
-50
0
Str
ain
(
)
ASTM C157
Sealedw/c = 0.30 Mortar
Internal Curing November 17, 2008 Slide 7 of 46
Chemical and Autogenous Shrinkage
Autogenous Shrinkage
Before Set
Chemical Shrinkage
= Autogenous Shrinkage
After Set
Chemical Shrinkage
>
Autogenous Shrinkage
=
Internal Voids
Vapor-Filled Voids
Autogenous Shrinkage
Internal Curing November 17, 2008 Slide 8 of 46
Outline
• Chemical and autogenous shrinkage• Water demand
– Internal void creation and drying fronts• Water supply
– LWA properties, water movement and water distribution• Powers model
– Influence of ‘internal’ water on hydration• Fluid absorption• Role of the pore size on shrinkage• Shrinkage measurements
– Unrestrained and restrained shrinkage in sealed and unsealed conditions
• Conclusions
Internal Curing November 17, 2008 Slide 9 of 46
0 1 2 3 4 5 6 7Age of Specimen (d)
0
0.01
0.02
0.03
0.04
0.05
Sh
rin
kag
e V
olu
me
(m
l/g c
eme
nt)
0 1 2 3 4 5 6 7Age of Specimen (d)
0
0.01
0.02
0.03
0.04
0.05
Sh
rin
kag
e V
olu
me
(m
l/g c
eme
nt)
Water Demand
0 1 2 3 4 5 6 7Age of Specimen (d)
0
0.01
0.02
0.03
0.04
0.05
Sh
rin
kag
e V
olu
me
(ml/g
cem
en
t)
0 1 2 3 4 5 6 7Age of Specimen (d)
0
0.01
0.02
0.03
0.04
0.05
Sh
rin
kag
e V
olu
me
(m
l/g c
eme
nt)
Cf × CS × αmax
Bentz, et. al, (1999)
Cf = Cement ContentCS = Chemical Shrinkageαmax = Degree of Hydration
Fin
al S
et
Fro
m V
icat
Chem ical ShrinkageAutogenous Shrinkage
Created Void
Space
Internal Curing November 17, 2008 Slide 10 of 46
Sealed vs. Unsealed Conditions
• Sealed conditions– Internal voids created due to chemical shrinkage
• Unsealed conditions– Internal voids plus moisture front created due to drying
Radlinska, et al., (2008)
Internal Curing November 17, 2008 Slide 11 of 46
Outline
• Chemical and autogenous shrinkage• Water demand
– Internal void creation and drying fronts• Water supply
– LWA properties, water movement and water distribution• Powers model
– Influence of ‘internal’ water on hydration• Fluid absorption• Role of the pore size on shrinkage• Shrinkage measurements
– Unrestrained and restrained shrinkage in sealed and unsealed conditions
• Conclusions
Internal Curing November 17, 2008 Slide 12 of 46
0 1 2 3 4 5 6 7Age of Specimen (Days)
0
0.01
0.02
0.03
0.04
0.05
Sh
rin
kag
e V
olu
me
(ml/
gce
m)
0 1 2 3 4 5 6 7Age of Specimen (Days)
0
0.01
0.02
0.03
0.04
0.05
Sh
rin
kag
e V
olu
me
(ml/
gce
m)
Water Supply
Chem ical ShrinkageAutogenous Shrinkage
MLWA × S × ϕLWA
Bentz, et. al, (1999)
MLWA = Mass of LWAS = Degree of SaturationϕLWA = Absorption Capacity
• Use LWA to supply additional water• Largest pores will empty first
1 10 100 1000 10000 100000Pore Diameter (nm )
0.00
0.05
0.10
0.15
0.20
0.25
0.30
0.35
0.40
Cu
mu
lati
ve V
olu
me
(mL
/g) LW A-K
LW A-H8 h Paste24 h Paste7 d Paste
0 24 48 72 96Age of Specimen (h)
-400
-300
-200
-100
0
100
200
300
Str
ain
(
)
25.3%k25.3%h19.4%CRCA
8 0 8 2 8 4 8 6 8 8 9 0 9 2 9 4 9 6 9 8 1 0 0Relative Humidity (% )
0
10
20
30
40
50
60
70
80
90
100
Per
cen
t o
f A
bso
rbed
Wat
er R
emai
ng
(%
)
LW A-HLW A-K
CRCA
Internal Curing November 17, 2008 Slide 13 of 46
Supply vs. Demand
Must Supply a sufficient volume of LWA (water) to satisfy demand in
sealed conditions
Bentz, et. al, (1999)
LWALWA
f
SM
CSC
Supply
DemandSupplyDemand
max1
LWA
fLWA S
CSCM
max
Internal Curing November 17, 2008 Slide 14 of 46
Monitoring Water Movement using X-ray
• Monitor density change– Volume of water changes,
density changes
• Composite theory model• Timing of water release• Water Travel Distance
– Proper sample orientation
tVVVVII VVWWPastePasteLWALWAMeasured exp0
X-Ray BeamSource
Detector
Sample
FOD
FDD
UsefulBeam
X-Ray BeamSource
Detector
Sample
FOD
FDD
UsefulBeam
ODD
X-Ray BeamSource
Detector
Sample
FOD
FDD
UsefulBeam
X-Ray BeamSource
Detector
Sample
X-Ray BeamSource
Detector
Sample
FOD
FDD
UsefulBeam
X-Ray BeamSource
Detector
Sample
FOD
FDD
UsefulBeam
ODD
Internal Curing November 17, 2008 Slide 15 of 46
Timing of water release
• LWA prism cast next to cement paste• Fixed position and macro-water movement
Mounting Screw Hole
LWA Paste
5 mm
Aluminum Tape
25 mm
25 mm
2.5 mm
Internal Curing November 17, 2008 Slide 16 of 46
Timing of water release
• Water remains in the pores of LWA until after set
Counts@i,LWA – Counts@3.5,LWA
0 4 8 12 16 20 24 28Age of Specimen (h)
-5000
-4000
-3000
-2000
-1000
0
Dif
fere
nce
in C
ou
nts
fr
om
In
itia
l Co
un
ts a
t 3.
5 h
-0.030
-0.025
-0.020
-0.015
-0.010
-0.005
0.000
Vo
id V
olu
me
(mL
/gce
m)
0 4 8 12 16 20 24 28Age of Specimen (h)
-5000
-4000
-3000
-2000
-1000
0
Dif
fere
nce
in C
ou
nts
fr
om
In
itia
l Co
un
ts a
t 3.
5 h
-0.030
-0.025
-0.020
-0.015
-0.010
-0.005
0.000
Vo
id V
olu
me
(mL
/gce
m)
0 4 8 12 16 20 24 28Age of Specimen (h)
-5000
-4000
-3000
-2000
-1000
0
Dif
fere
nce
in C
ou
nts
fr
om
In
itia
l Co
un
ts a
t 3.
5 h
-0.030
-0.025
-0.020
-0.015
-0.010
-0.005
0.000
Vo
id V
olu
me
(mL
/gce
m)
Water is lost from LWA
X-Ray Measurements
Initial Set
0 1 2 3 4 5 6 7Age of Specimen (d)
0
0.01
0.02
0.03
0.04
0.05
Sh
rin
kag
e V
olu
me
(ml/g
cem
en
t)
Internal Curing November 17, 2008 Slide 17 of 46
Water Distribution
• Need paste within close proximity to LWA
• Fine aggregate protects more paste than coarse aggregate
Internal Curing November 17, 2008 Slide 18 of 46
Monitoring Water Movement using X-ray
• Monitor density change– Volume of water changes,
density changes
• Composite theory model• Timing of water release• Water Travel Distance
– Proper sample orientation
tVVVVII VVWWPastePasteLWALWAMeasured exp0
X-Ray BeamSource
Detector
Sample
FOD
FDD
UsefulBeam
X-Ray BeamSource
Detector
Sample
FOD
FDD
UsefulBeam
ODD
X-Ray BeamSource
Detector
Sample
FOD
FDD
UsefulBeam
X-Ray BeamSource
Detector
Sample
X-Ray BeamSource
Detector
Sample
FOD
FDD
UsefulBeam
X-Ray BeamSource
Detector
Sample
FOD
FDD
UsefulBeam
ODD
Internal Curing November 17, 2008 Slide 19 of 46
Sample Orientation
• Sample was rotated to correct orientation
• Reduce the size of the ‘interface’
• Reduce Uncertainty
Paste Paste
LWA LWA
Interface Interface
0.0 mm 0.5 mm0.0 mm 0.5 mm 0.0 mm 0.5 mm0.0 mm 0.5 mm
Paste Paste
LWA LWA
Interface Interface
0.0 mm 0.5 mm0.0 mm 0.5 mm 0.0 mm 0.5 mm0.0 mm 0.5 mm
X-ray Source
Detector
Cement Paste
LWA
Detector
X-ray Source
Cement Paste
LWA
1 . 0 1 . 2 1 . 4 1 . 6 1 . 8 2 . 0 2 . 2 2 . 4 2 . 6 2 . 8 3 . 0P o s i t i o n ( m m )
0
5 0 0 0
1 0 0 0 0
1 5 0 0 0
2 0 0 0 0
2 5 0 0 0
3 0 0 0 0
3 5 0 0 0
4 0 0 0 0C
ou
nts
(\s
ec)
Paste LW AInterface
1 . 0 1 . 2 1 . 4 1 . 6 1 . 8 2 . 0 2 . 2 2 . 4 2 . 6 2 . 8 3 . 0P o s i t i o n ( m m )
0
5 0 0 0
1 0 0 0 0
1 5 0 0 0
2 0 0 0 0
2 5 0 0 0
3 0 0 0 0
3 5 0 0 0
4 0 0 0 0C
ou
nts
(\s
ec)
Paste LW AInterface
1 . 0 1 . 2 1 . 4 1 . 6 1 . 8 2 . 0 2 . 2 2 . 4 2 . 6 2 . 8 3 . 0P o s i t i o n ( m m )
0
5 0 0 0
1 0 0 0 0
1 5 0 0 0
2 0 0 0 0
2 5 0 0 0
3 0 0 0 0
3 5 0 0 0
4 0 0 0 0C
ou
nts
(\s
ec)
Paste LW AInterface
1 . 0 1 . 2 1 . 4 1 . 6 1 . 8 2 . 0 2 . 2 2 . 4 2 . 6 2 . 8 3 . 0P o s i t i o n ( m m )
0
5 0 0 0
1 0 0 0 0
1 5 0 0 0
2 0 0 0 0
2 5 0 0 0
3 0 0 0 0
3 5 0 0 0
4 0 0 0 0C
ou
nts
(\s
ec)
Paste LW AInterface
1 . 0 1 . 2 1 . 4 1 . 6 1 . 8 2 . 0 2 . 2 2 . 4 2 . 6 2 . 8 3 . 0P o s i t i o n ( m m )
0
5 0 0 0
1 0 0 0 0
1 5 0 0 0
2 0 0 0 0
2 5 0 0 0
3 0 0 0 0
3 5 0 0 0
4 0 0 0 0C
ou
nts
(\s
ec)
Paste LW AInterface
Angle of Orientation0.0 Degrees-2.5 Degrees-5.0 Degrees-10.0 Degrees
Internal Curing November 17, 2008 Slide 20 of 46
Water Travel Distance
• Water is able to move approximately 1.8 mm in first 75 hours
Counts@i.Paste – Counts@4.0,Paste
-2.0 -1.8 -1.6 -1.4 -1.2 -1.0 -0.8 -0.6 -0.4 -0.2 0.0Distance from Interface (mm)
-20
-10
0
10
20
30
40
50
60
70
80
Dif
fere
nc
e in
Co
un
ts f
rom
In
itia
l Co
un
ts (
4.0
h)
LW
A
-2.0 -1.8 -1.6 -1.4 -1.2 -1.0 -0.8 -0.6 -0.4 -0.2 0.0Distance from Interface (mm)
-20
-10
0
10
20
30
40
50
60
70
80
Dif
fere
nc
e in
Co
un
ts f
rom
In
itia
l Co
un
ts (
4.0
h)
LW
A
-2.0 -1.8 -1.6 -1.4 -1.2 -1.0 -0.8 -0.6 -0.4 -0.2 0.0Distance from Interface (mm)
-20
-10
0
10
20
30
40
50
60
70
80
Dif
fere
nc
e in
Co
un
ts f
rom
In
itia
l Co
un
ts (
4.0
h)
LW
A
-2.0 -1.8 -1.6 -1.4 -1.2 -1.0 -0.8 -0.6 -0.4 -0.2 0.0Distance from Interface (mm)
-20
-10
0
10
20
30
40
50
60
70
80
Dif
fere
nc
e in
Co
un
ts f
rom
In
itia
l Co
un
ts (
4.0
h)
LW
A
-2.0 -1.8 -1.6 -1.4 -1.2 -1.0 -0.8 -0.6 -0.4 -0.2 0.0Distance from Interface (mm)
-20
-10
0
10
20
30
40
50
60
70
80
Dif
fere
nc
e in
Co
un
ts f
rom
In
itia
l Co
un
ts (
4.0
h)
LW
A
-2.0 -1.8 -1.6 -1.4 -1.2 -1.0 -0.8 -0.6 -0.4 -0.2 0.0Distance from Interface (mm)
-20
-10
0
10
20
30
40
50
60
70
80
Dif
fere
nc
e in
Co
un
ts f
rom
In
itia
l Co
un
ts (
4.0
h)
LW
A
-2.0 -1.8 -1.6 -1.4 -1.2 -1.0 -0.8 -0.6 -0.4 -0.2 0.0Distance from Interface (mm)
-20
-10
0
10
20
30
40
50
60
70
80
Dif
fere
nc
e in
Co
un
ts f
rom
In
itia
l Co
un
ts (
4.0
h)
LW
A
Water is gained in the paste
7.25 h8.00 h9.00 h12.00 h24.00 h75.00 h
Internal Curing November 17, 2008 Slide 21 of 46
Outline
• Chemical and autogenous shrinkage• Water demand
– Internal void creation and drying fronts• Water supply
– LWA properties, water movement and water distribution• Powers model
– Influence of ‘internal’ water on hydration• Fluid absorption• Role of the pore size on shrinkage• Shrinkage measurements
– Unrestrained and restrained shrinkage in sealed and unsealed conditions
• Conclusions
Internal Curing November 17, 2008 Slide 22 of 46
0
20
40
60
80
100
Vo
lum
e P
erce
nt
of
Mat
eria
l
0 10 20 30 40 50Percent Lightweight Aggregate of Total Mixture (%)
55%
23%
51% 48% 44% 41% 37% 30% 26% 22%
LW A
NW A
W ater
Cement
14.3% k11.0%k7.3%k3.8%k 18.3%k
25.3% k/h 29.3% k 33.0%k43.0% h
23% 23% 23% 23% 23% 23% 23% 23% 23%
12%
22% 22% 22% 22% 22% 22% 22% 22% 22% 22%
Mixture Proportions
• Constant w/c of 0.30• Constant volume fraction of fine aggregate
of 55%
Internal Curing November 17, 2008 Slide 23 of 46
Powers Model
0 0.2 0.4 0.6 0.8 1Degree of Hydration
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
Vo
lum
e R
atio
0 0.2 0.4 0.6 0.8 1Degree of Hydration
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
Vo
lum
e R
atio
Capillary W ater
Gel W ater
Gel Solid
Cement
Chemical Shrinkage
w/c of 0.30
0.730 0.2 0.4 0.6 0.8 1
Degree of Hydration
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
Vo
lum
e R
atio
0 0.2 0.4 0.6 0.8 1Degree of Hydration
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
Vo
lum
e R
atio
w/c of 0.30 with 11.0 % LWA
Capillary W ater
Gel W ater
Gel Solid
Cement
Chemical ShrinkageLW A W ater
0.770 0.2 0.4 0.6 0.8 1
Degree of Hydration
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
Vo
lum
e R
atio
w/c of 0.30 with 25.3 % LWA
0 0.2 0.4 0.6 0.8 1Degree of Hydration
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
Vo
lum
e R
atio
Capillary W aterGel W ater
Gel Solid
Cement
0.83
LW A W ater
0 5 10 15 20 25 30 35Percent LW A-K (%)
0.70
0.75
0.80
0.85
0.90
0.95
1.00
Deg
ree
of
Hyd
rati
on
(%
)
Maxim um theoretical degree of hydration (w/c = 0.30)
0.73
0.77
0.83 0 25 50 75 100 125 150 175 200 225Age of Specimen (d)
3 0
4 0
5 0
6 0
7 0
8 0
Deg
ree
of
Hyd
rati
on
(%
)
0 25 50 75 100 125 150 175 200 225Age of Specimen (d)
3 0
4 0
5 0
6 0
7 0
8 0
Deg
ree
of
Hyd
rati
on
(%
)
0 25 50 75 100 125 150 175 200 225Age of Specimen (d)
3 0
4 0
5 0
6 0
7 0
8 0
Deg
ree
of
Hyd
rati
on
(%
)
0 25 50 75 100 125 150 175 200 225Age of Specimen (d)
3 0
4 0
5 0
6 0
7 0
8 0
Deg
ree
of
Hyd
rati
on
(%
)
25.3% k11.0% k0.0%
Sealed
Jensen and Hansen, 2001
Internal Curing November 17, 2008 Slide 24 of 46
Outline
• Chemical and autogenous shrinkage• Water demand
– Internal void creation and drying fronts• Water supply
– LWA properties, water movement and water distribution• Powers model
– Influence of ‘internal’ water on hydration• Fluid absorption• Role of the pore size on shrinkage• Shrinkage measurements
– Unrestrained and restrained shrinkage in sealed and unsealed conditions
• Conclusions
Internal Curing November 17, 2008 Slide 25 of 46
0 10 20 30 40 50 60 70 80 90 100 110 120
Time (min 1/2)
0
5
10
15
20
25
30
Ab
sorb
ed w
ater
(10-3
gra
m o
f w
ater
/ c
m3
of
pas
te)
Water Absorption
Average of 3 Samples
0 10 20 30 40 50 60 70 80 90 100 110 120
Time (min 1/2)
0
5
10
15
20
25
30
Ab
sorb
ed w
ater
(10-3
gra
m o
f w
ater
/ c
m3
of
pas
te)
0 10 20 30 40 50 60 70 80 90 100 110 120
Time (min 1/2)
0
5
10
15
20
25
30
Ab
sorb
ed w
ater
(10-3
gra
m o
f w
ater
/ c
m3
of
pas
te)
0 10 20 30 40 50 60 70 80 90 100 110 120
Time (min 1/2)
0
5
10
15
20
25
30
Ab
sorb
ed w
ater
(10-3
gra
m o
f w
ater
/ c
m3
of
pas
te)
0 10 20 30 40 50 60 70 80 90 100 110 120
Time (min 1/2)
0
5
10
15
20
25
30
Ab
sorb
ed w
ater
(10-3
gra
m o
f w
ater
/ c
m3
of
pas
te)
0 10 20 30 40 50 60 70 80 90 100 110 120
Time (min 1/2)
0
5
10
15
20
25
30
Ab
sorb
ed w
ater
(10-3
gra
m o
f w
ater
/ c
m3
of
pas
te)
55/0.35 - 28 d55/0.30 - 28 d55/0.25 - 28 d11.0% k - 28 d25.3% k - 28 d
Mortar
0.10 0.12 0.14 0.16 0.18 0.20
Total porosity excluding gel porosity
0
5
10
15
20
25
30
35
40
45
Ab
sorb
ed w
ate
r at
8 d
ays
(10-3
gra
m o
f w
ate
r / c
m3
of
pas
te)
0.10 0.12 0.14 0.16 0.18 0.20
Total porosity excluding gel porosity
0
5
10
15
20
25
30
35
40
45
Ab
sorb
ed w
ate
r at
8 d
ays
(10-3
gra
m o
f w
ate
r / c
m3
of
pas
te)
0.10 0.12 0.14 0.16 0.18 0.20
Total porosity excluding gel porosity
0
5
10
15
20
25
30
35
40
45
Ab
sorb
ed w
ate
r at
8 d
ays
(10-3
gra
m o
f w
ate
r / c
m3
of
pa
ste
)0.10 0.12 0.14 0.16 0.18 0.20
Total porosity excluding gel porosity
0
5
10
15
20
25
30
35
40
45
Ab
sorb
ed w
ate
r at
8 d
ays
(10-3
gra
m o
f w
ate
r / c
m3
of
pas
te)
0.10 0.12 0.14 0.16 0.18 0.20
Total porosity excluding gel porosity
0
5
10
15
20
25
30
35
40
45
Ab
sorb
ed w
ate
r at
8 d
ays
(10-3
gra
m o
f w
ate
r / c
m3
of
pas
te)
55/0.25 - 28 d55/0.30 - 28 d55/0.35 - 28 d11.0%k - 28 d25.3%k - 28 d
0.20 0.25 0.30 0.35 0.40
water - cement ratio
0
5
10
15
20
25
30
35
40
45
Ab
sorb
ed w
ate
r at
8 d
ays
(10-3
gra
m o
f w
ate
r /
cm3
of
pas
te)
0.20 0.25 0.30 0.35 0.40
water - cement ratio
0
5
10
15
20
25
30
35
40
45
Ab
sorb
ed w
ate
r at
8 d
ays
(10-3
gra
m o
f w
ate
r /
cm3
of
pas
te)
0.20 0.25 0.30 0.35 0.40
water - cement ratio
0
5
10
15
20
25
30
35
40
45
Ab
sorb
ed w
ate
r at
8 d
ays
(10-3
gra
m o
f w
ate
r /
cm3
of
pas
te)
0.20 0.25 0.30 0.35 0.40
water - cement ratio
0
5
10
15
20
25
30
35
40
45
Ab
sorb
ed w
ate
r at
8 d
ays
(10-3
gra
m o
f w
ate
r /
cm3
of
pas
te)
0.20 0.25 0.30 0.35 0.40
water - cement ratio
0
5
10
15
20
25
30
35
40
45
Ab
sorb
ed w
ate
r at
8 d
ays
(10-3
gra
m o
f w
ate
r /
cm3
of
pas
te)
Plain - 28 d11.0%k - 28 d25.3%k - 28 dPaste w/c = 0.30 - 28 d
Internal Curing November 17, 2008 Slide 26 of 46
ITZ Depercolation
Cement PasteNormal Weight AggregateLightweight AggregateITZ
0 5 10 15 20 25 30 35Volume Percent of
Lightweight Aggregate
0.00
0.01
0.02
0.03
0.04
0.05
0.06
0.07
0.08
0.09
0.10
Vo
lum
e F
ract
ion
(T
ota
l Vo
lum
e B
asis
)
0 5 10 15 20 25 30 35Volume Percent of
Lightweight Aggregate
0.00
0.01
0.02
0.03
0.04
0.05
0.06
0.07
0.08
0.09
0.10
Vo
lum
e F
ract
ion
(T
ota
l Vo
lum
e B
asis
)
Percolated NW A ITZ Paste
0 1 2 3 4 5 6 7 8
Time (d)
0
5
10
15
20
25
Ab
sorb
ed w
ater
(10-3
gra
m o
f w
ater
/ c
m3
of
pas
te)
0 1 2 3 4 5 6 7 8
Time (d)
0
5
10
15
20
25
Ab
sorb
ed w
ater
(10-3
gra
m o
f w
ater
/ c
m3
of
pas
te)
0 1 2 3 4 5 6 7 8
Time (d)
0
5
10
15
20
25
Ab
sorb
ed w
ater
(10-3
gra
m o
f w
ater
/ c
m3
of
pas
te)
0 1 2 3 4 5 6 7 8
Time (d)
0
5
10
15
20
25
Ab
sorb
ed w
ater
(10-3
gra
m o
f w
ater
/ c
m3
of
pas
te)
0 1 2 3 4 5 6 7 8
Time (d)
0
5
10
15
20
25
Ab
sorb
ed w
ater
(10-3
gra
m o
f w
ater
/ c
m3
of
pas
te)
Internal Curing November 17, 2008 Slide 27 of 46
Outline
• Chemical and autogenous shrinkage• Water demand
– Internal void creation and drying fronts• Water supply
– LWA properties, water movement and water distribution• Powers model
– Influence of ‘internal’ water on hydration• Fluid absorption• Role of the pore size on shrinkage• Shrinkage measurements
– Unrestrained and restrained shrinkage in sealed and unsealed conditions
• Conclusions
Internal Curing November 17, 2008 Slide 28 of 46
Measuring Pore Size
0 1 2 3 4 5 6 7Age of Specim en (d)
8 0
8 2
8 4
8 6
8 8
9 0
9 2
9 4
9 6
9 8
1 0 0
Rel
ativ
e H
um
idit
y (%
)
0 1 2 3 4 5 6 7Age of Specim en (d)
8 0
8 2
8 4
8 6
8 8
9 0
9 2
9 4
9 6
9 8
1 0 0
Rel
ativ
e H
um
idit
y (%
)
RT
V
RHr m
ln
2
25.3% k14.3% k7.3%k0.0%
LWA
MAXfLWA S
CSC
Supply
DemandM
Internal Curing November 17, 2008 Slide 29 of 46
Role of Pore Size on Shrinkage
1 10 100Pore Radius (nm)
0.00
0.05
0.10
0.15
0.20
0.25
0.30
Po
re V
olu
me
(ml/
gce
m)
1 10 100Pore Radius (nm)
0.00
0.05
0.10
0.15
0.20
0.25
0.30
Po
re V
olu
me
(ml/
gce
m)
1 10 100Pore Radius (nm)
0.00
0.05
0.10
0.15
0.20
0.25
0.30
Po
re V
olu
me
(ml/
gce
m)
1 10 100Pore Radius (nm)
0.00
0.05
0.10
0.15
0.20
0.25
0.30
Po
re V
olu
me
(ml/
gce
m)
Pore Solution
Empty Pores
Water from 7.3%k
(.016 ml/gcem)Water from 14.3%k
(.032 ml/gcem)Water from 25.3%k
(.053 ml/gcem)
spp KKr
S 112
3
spp KKr
S 112
3
1 10 100 1000 10000 100000 1000000Pore Radius (nm)
0.00
0.05
0.10
0.15
0.20
0.25
0.30
Po
re V
olu
me
(ml/
gce
m)
Affected Pore Region Unaffected PoresMixture
From Pore Size Distribution
From RH Measurements
From RH Measurements (corrected)
% Reduction of Shrinkage Predicted
0.0% 7.0 5.3 7.0 0%7.3%k 9.6 6.5 8.4 27%
14.3%k 11.0 7.4 9.7 36%25.3%k 19.0 10.8 16.5 63%
RT
V
RHr m
ln
2
spp KKr
S 112
3
Bentz, 1998
Kelvin Radius
Internal Curing November 17, 2008 Slide 30 of 46
Outline
• Chemical and autogenous shrinkage• Water demand
– Internal void creation and drying fronts• Water supply
– LWA properties, water movement and water distribution• Powers model
– Influence of ‘internal’ water on hydration• Fluid absorption• Role of the pore size on shrinkage• Shrinkage measurements
– Unrestrained and restrained shrinkage in sealed and unsealed conditions
• Conclusions
Internal Curing November 17, 2008 Slide 31 of 46
Unrestrained Shrinkage Procedure
• Measured using corrugated tube protocol for first 24 hrs
• Measured using ASTM C157 after 24 hrsData Conditioning
and AcquisitionCorrugated
TubeThreaded Adjustment Screw
Sample Holder
LVDT
Sant, et al., (2006)
Internal Curing November 17, 2008 Slide 32 of 46
Unrestrained Shrinkage in Sealed Conditions
0 7 14 21 28Age of Specim en (d)
-400
-300
-200
-100
0
100
200
300
400
Str
ain
(
)
0 7 14 21 28Age of Specim en (d)
-400
-300
-200
-100
0
100
200
300
400
Str
ain
(
)
0 7 14 21 28Age of Specim en (d)
-400
-300
-200
-100
0
100
200
300
400
Str
ain
(
)
0 7 14 21 28Age of Specim en (d)
-400
-300
-200
-100
0
100
200
300
400
Str
ain
(
)
Sealed33.0%k29.3%k25.3%k18.3%k14.3%k11.0%k7.3%k0.0%
Average of 3 Samples
LWA
MAXfLWA S
CSC
Supply
DemandM
Demand > Supply
Supply > Demand
0 5 10 15 20 25 30 35Percent LW A-K (%)
0
1
2
3
4
5
6
7
Ag
e o
f S
pec
imen
(d
)
Tim e to onset of shrinkage
Mixtures do notshrink
Internal Curing November 17, 2008 Slide 33 of 46
Water Demand
0 1 2 3 4 5 6 7Age of Specimen (d)
0
0.01
0.02
0.03
0.04
0.05
Sh
rin
kag
e V
olu
me
(m
l/g c
eme
nt)
0 1 2 3 4 5 6 7Age of Specimen (d)
0
0.01
0.02
0.03
0.04
0.05
Sh
rin
kag
e V
olu
me
(m
l/g c
eme
nt)
0 1 2 3 4 5 6 7Age of Specimen (d)
0
0.01
0.02
0.03
0.04
0.05
Sh
rin
kag
e V
olu
me
(ml/g
cem
en
t)
0 1 2 3 4 5 6 7Age of Specimen (d)
0
0.01
0.02
0.03
0.04
0.05
Sh
rin
kag
e V
olu
me
(m
l/g c
eme
nt)
Fin
al S
et
Fro
m V
icat
Chem ical ShrinkageAutogenous Shrinkage
Created Void
Space
0 1 2 3 4 5 6 7Age of Specim en (d)
0
0.01
0.02
0.03
0.04
0.05
Vo
id V
olu
me
(ml/g
cem
ent)
0
2
4
6
8
10
12
14
16
18
20
22
Pe
rcen
t L
WA
-K (
%)
Voids Created
7.3%k
11.0%k
14.3% k
3.8%k
0 5 10 15 20 25 30 35Percent LW A-K (%)
0
1
2
3
4
5
6
7
Ag
e o
f S
pec
imen
(d
)
Mixtures do notshrink
Tim e to water depletionTim e to onset of shrinkage
0 5 10 15 20 25 30 35Percent LW A-K (%)
0
1
2
3
4
5
6
7
Ag
e o
f S
pec
imen
(d
)
Mixtures do notshrink
Internal Curing November 17, 2008 Slide 34 of 46
Unrestrained Shrinkage in Unsealed Conditions
Average of 3 Samples
0 7 14 21 28Age of Specim en (d)
-800
-600
-400
-200
0
200
400
Str
ain
(
)
0 7 14 21 28Age of Specim en (d)
-800
-600
-400
-200
0
200
400
Str
ain
(
)
0 7 14 21 28Age of Specim en (d)
-800
-600
-400
-200
0
200
400
Str
ain
(
)
0 7 14 21 28Age of Specim en (d)
-800
-600
-400
-200
0
200
400
Str
ain
(
)
U nsealed33.0%k29.3%k25.3%k18.3%k14.3%k11.0%k7.3%k0.0%
U nsealed33.0%k29.3%k25.3%k11.0%k7.3%k0.0%
U nsealed25.3% k11.0% k7.3% k0.0%
U nsealed25.3%k0.0%
LWA
MAXfLWA S
CSC
Supply
DemandM
Demand > Supply
0 7 14 21 28Age of Specimen (d)
-800
-700
-600
-500
-400
-300
-200
-100
0
Str
ain
(
)
0.0% Unsealed0.0% Sealed
Internal Curing November 17, 2008 Slide 35 of 46
Effects of Drying
0 5 10 15 20 25 30 35Percent Lightweight Aggregate (%)
-500
-400
-300
-200
-100
0
100
200
300
400
500
Str
ain
(
)
7 day free shrinkage (sealed)7 day free shrinkage (unsealed)
Internal Curing November 17, 2008 Slide 36 of 46
Restrained Shrinkage Procedure
• Measure the cracking potential
Internal Curing November 17, 2008 Slide 37 of 46
0 2 4 6 8 10 12 14 16 18 20Age of Specim en (d)
-60
-50
-40
-30
-20
-10
0
10
Str
ain
(
)
Restrained Shrinkage in Sealed Conditions
Typical Response of 3 Samples
0 2 4 6 8 10 12 14 16 18 20Age of Specim en (d)
-60
-50
-40
-30
-20
-10
0
10
Str
ain
(
)
0 2 4 6 8 10 12 14 16 18 20Age of Specim en (d)
-60
-50
-40
-30
-20
-10
0
10
Str
ain
(
)
0 2 4 6 8 10 12 14 16 18 20Age of Specim en (d)
-60
-50
-40
-30
-20
-10
0
10
Str
ain
(
)
LWA
MAXfLWA S
CSC
Supply
DemandM
Sealed25.3% k14.3% k11.0% k7.3% k3.8% k0.0%
Sealed25.3% k11.0% k7.3% k3.8% k0.0%
Sealed25.3% k3.8% k0.0%
Sealed25.3% k0.0%
0 5 10 15 20 25 30 35Percent LW A-K (%)
0
5
10
15
20
25
30
Ag
e o
f S
pec
imen
(d
)
Tim e of cracking (sealed) Mixtures did not crack
Internal Curing November 17, 2008 Slide 38 of 46
Restrained Shrinkage in Unsealed Conditions
0 2 4 6 8 10 12 14Age of Specimen (d)
-60
-50
-40
-30
-20
-10
0
10
Str
ain
(
)
0 2 4 6 8 10 12 14Age of Specimen (d)
-60
-50
-40
-30
-20
-10
0
10
Str
ain
(
)
0 2 4 6 8 10 12 14Age of Specimen (d)
-60
-50
-40
-30
-20
-10
0
10
Str
ain
(
)
Unsealed33.0% k29.3% k25.3% k14.3% k11.0% k7.3% k0.0%
Unsealed25.3% k14.3% k11.0% k7.3% k0.0%
Unsealed25.3% k0.0%
Typical Response of 3 Samples
LWA
MAXfLWA S
CSC
Supply
DemandM
0 5 10 15 20 25 30 35Percent LW A-K (%)
0
5
10
15
20
25
30A
ge
of
Sp
ecim
en (
d)
Tim e of cracking (unsealed) Mixtures did not crack
0 5 10 15 20 25 30 35Percent LW A-K (%)
0
5
10
15
20
25
30A
ge
of
Sp
ecim
en (
d)
Tim e of cracking (sealed)Tim e of cracking (unsealed)
Mixtures did not crack
Internal Curing November 17, 2008 Slide 39 of 46
0 7 14 21 28Age of Specimen (d)
-400
-200
0
200
400
600
800
Str
ain
(
)
Sealed43%h25.3%k0.0%
0 2 4 6 8 10Age of Specimen (d)
-60
-50
-40
-30
-20
-10
0
10
Str
ain
(
)
Unsealed43% h25.3% k0.0%
Spatial Considerations
Same Volume of Water, Different Spacing
Average of 3 Samples
Same Volume of Water, Different Spacing
Typical Response of 3 Samples
LWA-H LWA-K
Internal Curing November 17, 2008 Slide 40 of 46
0 7 14 21 28Age of Specimen (d)
-400
-200
0
200
400
600
800
Str
ain
(
)
Sealed25.3%k25.3%h0.0%
Volume of Water Considerations
Average of 3 SamplesTypical Response of 3 Samples
Same Volume of Aggregate, Different Volume of Water
0 2 4 6 8 10Age of Specimen (d)
-60
-50
-40
-30
-20
-10
0
10
Str
ain
(
)
Unsealed25.3% k25.3% h0.0%
Same Volume of Aggregate, Different Volume of Water
LWA-H LWA-K
Internal Curing November 17, 2008 Slide 41 of 46
Conclusions
• Define properties of LWA that make it an effective
internal curing agent– High absorption and needs to desorb (give up) water– Pores larger than pores of cement paste
Internal Curing November 17, 2008 Slide 42 of 46
Conclusions
• Monitor water movement from LWA to
cement paste– Water does not leave until after set– Water can travel up to 1.8 mm in first 75 hours
0 4 8 12 16 20 24 28Age of Specimen (h)
-5000
-4000
-3000
-2000
-1000
0
Dif
fere
nc
e i
n C
ou
nts
fr
om
In
itia
l C
ou
nts
at
3.5
h
-0.030
-0.025
-0.020
-0.015
-0.010
-0.005
0.000
Vo
id V
olu
me
(mL
/gce
m)
-2.0 -1.8 -1.6 -1.4 -1.2 -1.0 -0.8 -0.6 -0.4 -0.2 0.0Distance from Interface (mm)
-20
-10
0
10
20
30
40
50
60
70
80
Dif
fere
nce
in C
ou
nts
fro
m
Init
ial C
ou
nts
(4.
0 h
)
LW
A
Internal Curing November 17, 2008 Slide 43 of 46
Conclusions
• Examine the fluid absorption characteristics– Reduce water absorption due to continued
hydration or depercolate of NWA ITZ– Mixtures with LWA perform like mixtures with
lower w/c
0.20 0.25 0.30 0.35 0.40
water - cement ratio
0
5
10
15
20
25
30
35
40
45
Ab
sorb
ed w
ate
r at
8 d
ays
(10-3
gra
m o
f w
ate
r / c
m3
of
pas
te)
0.10 0.12 0.14 0.16 0.18 0.20
Total porosity excluding gel porosity
0
5
10
15
20
25
30
35
40
45
Ab
sorb
ed w
ate
r at
8 d
ays
(10-3
gra
m o
f w
ate
r / c
m3
of
pas
te)
Internal Curing November 17, 2008 Slide 44 of 46
Conclusions
• Measure the unrestrained and restrained shrinkage in sealed and unsealed conditions– Supply sufficient water to satisfy demand from
chemical shrinkage and drying– Reduce shrinkage cracking with sufficient supply of
water
0 5 10 15 20 25 30 35Percent LW A-K (%)
0
5
10
15
20
25
30
Ag
e o
f S
pec
imen
(d
)
Tim e of cracking (sealed)Tim e of cracking (unsealed)
Mixtures did not crack
0 5 10 15 20 25 30 35Percent Lightweight Aggregate (%)
-500
-400
-300
-200
-100
0
100
200
300
400
500
Str
ain
(
)
7 day free shrinkage (sealed)7 day free shrinkage (unsealed)
Internal Curing November 17, 2008 Slide 45 of 46
Acknowledgements
Professor Jason Weiss
Professor John Haddock
Dr. Tommy Nantung
Dale Bentz
Jack Spaulding
John Roberts
Mark Baker
Janet Lovell
Gaurav Sant
Scott Kobs
Bill Wilson
Dan Matson
Katie Funk
Peter Briatka
Gary Filbert
Erin Cutler
Aleksandra Radlinska
Arnd Eberhardt
Brooks Bucher
Kevin Coates
Kevin Gerst
Mohammad Pour-Ghaz
Javier Castro
Kambiz Raoufi
Mike Norfleet
Mukul Dehadrai
Chadi El Mohtar
Internal Curing November 17, 2008 Slide 46 of 46
Questions
Internal Curing in Cementitious Systems Made Using Saturated
Lightweight Aggregate
Master’s DefenseRyan Henkensiefken
November 17th, 2008
Internal Curing November 17, 2008 Slide 47 of 46
References
• Bentz, D.P., Garboczi, E.J. and D.A. Quenard (1998). “Modelling drying shrinkage in reconstructed porous materials: application to porous Vycor glass,” Modelling Simulation Material Science Engineering 6: 211-236.
• Bentz, D. P. and K. A. Snyder (1999). "Protected paste volume in concrete: Extension to internal curing using saturated lightweight fine aggregate." Cement and Concrete Research 29(11): 1863
• Jensen, O.M. and P.F. Hansen (2001). “Autogenous deformation and RH-change in perspective,” Cement and Concrete Research 31(12): 1859.
• Neville, A.M., Properties of Concrete, Pearson Education, p. 411.• Radlinska, A., F. Rajabipour, B. Bucher, R. Henkensiefken, G. Sant,
and J. Weiss, Shrinkage mitigation strategies in cementitious systems: A closer look at sealed and unsealed material behavior, in Accepted for publication in the Transportation Research Record. 2008.
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