internal curing in cementitious systems made using saturated lightweight aggregate

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


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)


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


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


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


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

(

)


-400

-350

-300

-250

-200

-150

-100

-50

0

Str

ain

(

)

ASTM C157

Sealedw/c = 0.30 Mortar


Chemical and Autogenous Shrinkage


Before Set

Chemical Shrinkage

= Autogenous Shrinkage

After Set

Chemical Shrinkage

>


=

Internal Voids

Vapor-Filled Voids



Outline






• Conclusions


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

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

0.01

0.02

0.03

0.04

0.05

Sh

rin

kag

e V

olu

me

(ml/g

cem

en

t)


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


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)


Outline






• Conclusions


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


MLWA × S × ϕLWA


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


Supply vs. Demand

Must Supply a sufficient volume of LWA (water) to satisfy demand in

sealed conditions


LWALWA

f

SM

CSC

Supply

DemandSupplyDemand

max1

LWA

fLWA S

CSCM

max


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


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


Timing of water release

• Water remains in the pores of LWA until after set

Counts@i,LWA – [email protected],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

0.01

0.02

0.03

0.04

0.05

Sh

rin

kag

e V

olu

me

(ml/g

cem

en

t)


Water Distribution

• Need paste within close proximity to LWA

• Fine aggregate protects more paste than coarse aggregate


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


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


Water Travel Distance

• Water is able to move approximately 1.8 mm in first 75 hours

[email protected] – [email protected],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


-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


-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


-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


-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


-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


-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


Outline






• Conclusions


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%


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

0.1

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

0.1

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

0.1

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


Outline






• Conclusions


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


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


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


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


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


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


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


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


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


ITZ Depercolation

Cement PasteNormal Weight AggregateLightweight AggregateITZ

0 5 10 15 20 25 30 35Volume Percent of


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


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)


Outline






• Conclusions


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 (%

)


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


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)


0.00

0.05

0.10

0.15

0.20

0.25

0.30

Po

re V

olu

me

(ml/

gce

m)


0.00

0.05

0.10

0.15

0.20

0.25

0.30

Po

re V

olu

me

(ml/

gce

m)


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


Outline






• Conclusions


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)


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

(

)


-400

-300

-200

-100

0

100

200

300

400

Str

ain

(

)


-400

-300

-200

-100

0

100

200

300

400

Str

ain

(

)


-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%


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


Water Demand


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

0.01

0.02

0.03

0.04

0.05

Sh

rin

kag

e V

olu

me

(m

l/g c

eme

nt)


0

0.01

0.02

0.03

0.04

0.05

Sh

rin

kag

e V

olu

me

(ml/g

cem

en

t)


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


Created Void

Space


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

)


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

)



Unrestrained Shrinkage in Unsealed Conditions



-800

-600

-400

-200

0

200

400

Str

ain

(

)


-800

-600

-400

-200

0

200

400

Str

ain

(

)


-800

-600

-400

-200

0

200

400

Str

ain

(

)


-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


-800

-700

-600

-500

-400

-300

-200

-100

0

Str

ain

(

)

0.0% Unsealed0.0% Sealed


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)


Restrained Shrinkage Procedure

• Measure the cracking potential


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


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%


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



-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


Same Volume of Water, Different Spacing


LWA-H LWA-K



-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


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


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)


-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


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


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


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)


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)


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


Questions

Internal Curing in Cementitious Systems Made Using Saturated


Master’s DefenseRyan Henkensiefken

November 17th, 2008


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.

internal curing in cementitious systems made using saturated lightweight aggregate

Education

timing of water release

water remaing

water supply0

restrained shrinkage

sufficient volume of

lwah lwa lwa

chemical shrinkage voidmax

monitoring water movement