An Investigation of Prediction Model for AutAn Investigation of Prediction Model for Autogenous Shrinkage/Expansion Strain of Lowogenous Shrinkage/Expansion Strain of Low

-shrinkage HSC-shrinkage HSC

Fourth International Seminar on Self-desiccation and Its Importance in Concrete Technology 20/June/05, Gaithersburg, Maryland, USA

Makoto TANIMURA, Yuji MITANIMakoto TANIMURA, Yuji MITANI Taiheiyo Cement Corporation, JapanTaiheiyo Cement Corporation, Japan

Ryoichi SATORyoichi SATO Hiroshima University, JapanHiroshima University, Japan

1

Influence of dosage of Expansive additive and/or shrinInfluence of dosage of Expansive additive and/or shrinkage reducerkage reducerPrediction model for autogenous shrinkage/expansion sPrediction model for autogenous shrinkage/expansion strain of low-shrinkage/expansion HSCs (required in practtrain of low-shrinkage/expansion HSCs (required in practice)ice)

Importance of autogenous shrinkage in HSCImportance of autogenous shrinkage in HSC Necessity of reducing autogenous shrinkageNecessity of reducing autogenous shrinkage----- well known!! (JCI committee 1996 & 2002)----- well known!! (JCI committee 1996 & 2002)

Effectiveness of expansive additive, shrinkage reduceEffectiveness of expansive additive, shrinkage reducer, High Cr, High C22S and low CS and low C33A-cementA-cement Effectiveness for reduction of restrained-shrinkage stEffectiveness for reduction of restrained-shrinkage stress, improvement of structural performance of RC memress, improvement of structural performance of RC membersbers

ObjectivesObjectives

(Tazawa & Miyazawa, at least in 1994)

(by authors, presented by SUZUKI)

BackgroundBackground 2

W/(C+EX)= 0.3, W= 175 kg/mW/(C+EX)= 0.3, W= 175 kg/m33

Slump flow value; 500-700 mmSlump flow value; 500-700 mm Targeted concrete strength; 70 N/mmTargeted concrete strength; 70 N/mm22

Combinations of key-materialsCombinations of key-materials

Cem.Cem. EX (kg/mEX (kg/m33)) 00 3030 4040 5050 6060

Ordi-nOrdi-naryary

SRASRA(kg/m(kg/m33))

006699

1212

N-0-0N-0-0N-0-6N-0-6N-0-9N-0-9N-0-12N-0-12

N-30-0N-30-0N-30-6N-30-6N-30-9N-30-9

N-30-12N-30-12

N-40-0N-40-0N-40-6N-40-6N-40-9N-40-9N-40-12N-40-12

N-50-0N-50-0N-50-6N-50-6N-50-9N-50-9N-50-12N-50-12

N-60-0N-60-0N-60-6N-60-6N-60-9N-60-9

N-60-12N-60-12

Belite-Belite-richrich

Low hLow heateat

006699

1212

L-0-0L-0-0L-0-6L-0-6L-0-9L-0-9

L-0-12L-0-12

L-30-0L-30-0L-30-6L-30-6L-30-9L-30-9L-30-12L-30-12

L-40-0L-40-0L-40-6L-40-6L-40-9L-40-9

L-40-12L-40-12

L-50-0L-50-0L-50-6L-50-6L-50-9L-50-9

L-50-12L-50-12

L-60-0L-60-0L-60-6L-60-6L-60-9L-60-9L-60-12L-60-12

Mixture proportioningMixture proportioning

EX; Lime-based expansive additiveEX; Lime-based expansive additive SRA; Lower-alcohol alkyleneoxide adduct-based shrinkage reduceSRA; Lower-alcohol alkyleneoxide adduct-based shrinkage reducerr

3

FormworkPolystyrene sheet

Polyester film

Gauge plug

Concrete specimen(100×100×400mm)

Displacement transducer

Polytetrafluoroethylene sheet

Polyester film

Before demoldingBefore demolding Testing Method for Autogenous Shrinkage/Expansion of Concrete Testing Method for Autogenous Shrinkage/Expansion of Concrete After demoldingAfter demolding JIS A 1129 (contact-type strain gage) JIS A 1129 (contact-type strain gage)

Autogenous shrinkage/expansion strain=Autogenous shrinkage/expansion strain= (Measured strain) – (thermal strain)(Measured strain) – (thermal strain)

Measurement of autogenous length changeMeasurement of autogenous length change

JCI method

(originally proposed by Tazawa & Miyazawa)

4

20oC

coefficient of thermal expansion of concrete; assumed to be 10 x 10-6/oC

ist 0t

)t,t(' isas)t,t(' 0as

)t,t(' 0ds)t,t(' 0cs

)t,t(' iscs

t AgeShrinkage

(Initial setting)

(Start of drying)

ist 0t

)t,t(' isas)t,t(' 0as

)t,t(' 0ds)t,t(' 0cs

)t,t(' iscs

t AgeShrinkage

(Initial setting)

(Start of drying)

: autogenous shrinkage strain from initial setting time

: drying shrinkage strain

: total shrinkage strain from initial setting time ( )

: total shrinkage strain from start of drying

: autogenous shrinkage strain from start of drying

According to JSCE Design Code 2002

Investigation on autogenous shrinkage

5

)t,t(' isas)t,t(' 0ds

)t,t(' 0as)t,t(' 0cs)t,t(' iscs )t,t(')t,t(' 0dsisas

Definition of strain in this studyDefinition of strain in this study

AS of LPC-HSC is obviously small compared with OPC-HSC.AS of LPC-HSC is obviously small compared with OPC-HSC. Prediction by JSCE Code is in good agreement with Prediction by JSCE Code is in good agreement with measurement. measurement.

Effectiveness of Berite-rich low heat Portland cementEffectiveness of Berite-rich low heat Portland cement

-500

-400

-300

-200

-100

0

0.1 1 10 100

N-0-0-measured valueN-0-0-calculated valueL-0-0-measured valueL-0-0-calculated value

Au

toge

nou

s sh

rin

kag

e st

rain

(x1

0-6

)

Age (days)

6

JSCE 　 0.4

LPC

JSCE Code-2002

OPC+40%

‐40%

‐40%

+40%

(by Miyazawa et al.)

Initial set

0

0.2

0.4

0.6

0.8

1

0 3 6 9 12 15

Ordinary Portland cement

Low-heat Portland cement

Rat

io o

f au

toge

nou

s sh

rin

kag

e st

rain

(x1

0-6)

Unit SRA content (kg/m3)

SRA is obviously effective in reducing AS.SRA is obviously effective in reducing AS. AS of LPC-based HSC is almost cancelled by adding SRA.AS of LPC-based HSC is almost cancelled by adding SRA.

-500

-400

-300

-200

-100

0

0.1 1 10 100

N-0-0

N-0-6

N-0-9

N-0-12

L-0-0

L-0-6

L-0-9

L-0-12Au

toge

nou

s sh

rin

kag

e st

rain

(x1

0-6)

Age (days)

Ras=0.0008SRA2-0.035SRA+1

Ras=0.0024SRA2-0.094SRA+1

始発

7Effectiveness of shrinkage reducing agent(SRA)Effectiveness of shrinkage reducing agent(SRA)

LPC

OPC

Age: 91days

LPC

OPC

Initial set

-600

-400

-200

0

200

0.1 1 10 100

N-0-0N-30-0N-40-0N-50-0N-60-0

Au

toge

nou

s ex

pan

sion

/sh

rin

kag

e st

rain

(x1

0-6)

Age (days)

(Expansion)

(Shrinkage)

-200

0

200

400

600

800

0.1 1 10 100

L-0-0L-30-0L-40-0L-50-0L-60-0

Au

toge

nou

s ex

pan

sion

/sh

rin

kag

e st

rain

(x1

0-6)

Age (days)

(Expansion)

(Shrinkage)

Effectiveness of expansive additive (EX)Effectiveness of expansive additive (EX) 8

EX effectively compensate AS.EX effectively compensate AS. Absolute expansion strain is dependent upon AS behavior of rAbsolute expansion strain is dependent upon AS behavior of reference HSC.eference HSC. Combination of LPC & EX; achievement of expansive HSCsCombination of LPC & EX; achievement of expansive HSCs

Initial set

LPCOPC

50%

80%

0

200

400

600

800

0 10 20 30 40 50 60 70 80

Ordinary Portland cement

Low-heat Portland cement

Com

pen

sati

on o

f au

toge

nou

s sh

rin

kag

e (x

10-6

)Unit EX content (kg/m 3)

Compensation of AS is more significant for LPC-based HSC.Compensation of AS is more significant for LPC-based HSC. Reason; difference in early-age mechanical property, etc.Reason; difference in early-age mechanical property, etc.

Description of the effect of expansive additive Description of the effect of expansive additive (EX)(EX)

εex∞=0.144EX2+4.47EX

εex∞=0.061EX2+5.82EX

compensation of AS from final set

of EX-added HSC

Definition of compensation of AS

9

LPC

OPCAge: 91days

istAge

t

fst

)t,t(' isas

)t,t( isex

)t,t( fsex

Exp

ansi

onS

hrin

kage

(Initial setting)

(Final setting)AS from initial set of EX-added HSC

0

200

400

600

800

1000

1200

0 10 20 30 40 50 60 70 80

L-0L-6L-9L-12

Com

pen

sati

on o

f au

toge

nou

s sh

rin

kag

e (x

10-6

)

Unit EX content (kg/m 3)

0

200

400

600

800

1000

1200

0 10 20 30 40 50 60 70 80

N-0N-6N-9N-12

Com

pen

sati

on o

f au

toge

nou

s sh

rin

kag

e (x

10-6

)

Unit EX content (kg/m 3)

Effectiveness of combined use of EX and SRAEffectiveness of combined use of EX and SRA

No SRA

εex+sra∞=0.142EX2

+3.08EX

εex+sra∞=0.278EX2

+0.039EX

No SRA

SRA=6～ 12 kg/m3

10

Significant synergistic effect is observed when EX content of Significant synergistic effect is observed when EX content of more than 40 kg/mmore than 40 kg/m33

Reason; delicate change of hydration reaction of EX and Reason; delicate change of hydration reaction of EX and cement by adding SRA, etc.cement by adding SRA, etc. --- further investigations is needed for detailed explanation,--- further investigations is needed for detailed explanation, from both chemical and mechanical point of view.from both chemical and mechanical point of view.

LPCOPC

Age: 91daysAge: 91days

Synergistic effect

Synergistic effect

SRA=6～ 12 kg/m3

11Definition of compensation of AS for EX+SRA-Definition of compensation of AS for EX+SRA-added HSCadded HSC

Exp

ansi

on

Age

Shr

inka

ge

(Initial setting)

(Final setting)

istt

fst

)t,t(' isas

)t,t( issraex

)t,t( fssraex

AS from initial set of SRA-added HSC

compensation of AS from final set of EX+SRA-added HSC

AS from initial set of EX+SRA-added HSC

Basic equation; JSCE Code equation for AS

}])tt(aexp{1[')t,t(' bisasisas

)}C/W(2.7exp{3070'as

End valueDevelopment propertya=0.6, b=0.5 for W/C=0.3

Initial set

12Prediction model for autogenous shrinkage/expansion Prediction model for autogenous shrinkage/expansion strain, considered effect of EX and/or SRA strain, considered effect of EX and/or SRA

0

0.2

0.4

0.6

0.8

1

1.2

0.1 1 10 100

N-0-0N-0-6N-0-9N-0-12N-0-0 (Eq.(2))L-0-0L-0-6L-0-9L-0-12L-0-0 (Eq.(2))

Age (days)

)t,91('/)t,t(' isasisas

Prediction model considering SRA effectPrediction model considering SRA effect

}])tt(aexp{1['R)t,t(' bisasasisas

1SRA035.0SRA0008.0R 2as

1SRA094.0SRA0024.0R 2as

JSCE Code

Average of “a” & “b” obtained from least square method for

SRA-added HSC;a=0.62 ， b=0.48

Same as that of JSCE Code

Reduction of end value

13

LPC

OPC

Average of “c” & “d” obtained from least square method for

EX-added HSC; c=0.8 ， d=0.5 for OPC c=0.5, d=0.6 for LPC

0

0.2

0.4

0.6

0.8

1

1.2

0.1 1 10 100

N-30-0N-40-0N-50-0N-60-0N-40-0 (Eq.(4))L-30-0L-40-0L-50-0L-60-0L-40-0 (Eq.(4))

Age (days)

)t,91(/)t,t( fsexfsex

Prediction model considering EX effectPrediction model considering EX effect

EX82.5EX061.0 2ex

}])tt(cexp{1[)t,t( dfsexfsex

According to values below

Development property of compensation of AS

EX47.4EX144.0 2ex

14

LPC

OPCEnd value of compensation of AS

OPC; c=0.8, d=0.5

LPC; c=0.5, d=0.6

LPC

OPC

Same as that of EX-HSC

End value of compensation of AS for EX+SRA-HSC

Prediction model considering EX+SRA effectPrediction model considering EX+SRA effect

0

0.2

0.4

0.6

0.8

1

0.1 1 10 100

材齢（日）

εex

sra

＋t

/ε（

）ex

sra

＋91

（）

L- 30- 6L- 40- 6L- 50- 6L- 60- 6L- 30- 9L- 40- 9L- 50- 9L- 60- 9L- 30- 12L- 40- 12L- 50- 12L- 60- 12L- 40- 6 c=0. 5, d=0. 6（ ）0

0.2

0.4

0.6

0.8

1

0.1 1 10 100

材齢（日）

εex

sra

＋t

/ε（

）ex

sra

＋91

（）

N- 30- 6N- 40- 6N- 50- 6N- 60- 6N- 30- 9N- 40- 9N- 50- 9N- 60- 9N- 30- 12N- 40- 12N- 50- 12N- 60- 12N- 40- 6( c=0. 8, d=0. 5）

EX039.0EX278.0 2sraex

EX08.3EX142.0 2sraex

}])tt(cexp{1[)t,t( dfssraexfssraex

Average;c=0.5, d=0.6

15

Development property of compensation of AS

Age (days) Age (days)

LPCOPC

Average;c=0.8, d=0.5

-500

-400

-300

-200

-100

0

-500 -400 -300 -200 -100 0

N-7daysN-28daysN-91daysL-7daysL-28daysL-91days

Cal

cula

ted

val

ue

(x10

-6)

Measured value (x10 -6)

+20%

-20%

SRA-added HSC

Prediction accuracy; 20 %

16Accuracy of prediction modelAccuracy of prediction model

-400

-200

0

200

400

600

800

-400 -200 0 200 400 600 800

Measured value (x10-6)

Cal

cula

ted

val

ue

(x10

-6)

N-3daysN-7daysN-28daysN-91daysL-3daysL-7daysL-28daysL-91days

+20%

-20%

-200

0

200

400

600

800

1000

-200 0 200 400 600 800 1000

Measured value (x10-6)

Cal

cula

ted

val

ue

(x10

-6)

N-3daysN-7daysN-28daysN-91daysL-3daysL-7daysL-28daysL-91days

+20%

-20%

EX-added HSC

EX+SRA-added HSC

It is surely confirmed that HSCs with various low shrinIt is surely confirmed that HSCs with various low shrinkage/expansion strain properties can be produced by sole/kage/expansion strain properties can be produced by sole/combined use of investigated materials.combined use of investigated materials.

It is demonstrated that the investigated equations have It is demonstrated that the investigated equations have accuracy of 20 % for predicting autogenous shrinkage /eaccuracy of 20 % for predicting autogenous shrinkage /expansion strain of low-shrinkage/expansion HSCs.xpansion strain of low-shrinkage/expansion HSCs.(Further investigation is needed for temperature effect) (Further investigation is needed for temperature effect)

ConclusionsConclusions 17

On the other hand, addition of EX and/or SRA influence the strength of HSC. Therefore, suitable dosage of EX and/or SRA as well as W/C should be determined by considering both low-shrinkage performance and high-strength performance.

Thank you !!Thank you !!

High-mechanical performance and high-durability

Necessity of low-shrinkage HSCNecessity of low-shrinkage HSC

Significant autogenous shrinkage

Tensile restrained-stress before loading

Deterioration of serviceability performance of RC members

Low-shrinkage HSC-High cracking -High cracking resistanceresistance-Durable RC structure-Durable RC structure

High-strength

Low shrinkage

High-flowability

Assignment

Additional performance

generalization

Approach for low-shrinkage HSCApproach for low-shrinkage HSC

Belite-rich Portland cement

Low-heat Portland cement

Special admixturesLow-shrinkage cement

Expansive additive

Shrinkage reducing agent

Au

toge

nou

s st

rain

LPCLPC

Conventional HSCConventional HSC

EX+SRAEX+SRA

EXEX

SRASRA

Combination

Expansion rather than shrinkage

Au

toge

nou

s st

rain

Age

Control of autogenous shrinkage

Autogenous shrinkage of cement paste with W/C of 0.3 (x10Autogenous shrinkage of cement paste with W/C of 0.3 (x10 -6-6) )

= 2.15= 2.15 ＊＊ (C(C33S%) – 5.49S%) – 5.49 ＊＊ (C(C22S%) + 68.7S%) + 68.7 ＊＊ (C(C33A%) + 48.5A%) + 48.5 ＊＊ (C(C44AFAF

%)%)

where,where,

(C(C33S%): Content of CS%): Content of C33S (mass%)S (mass%)

………………… ………………… [by Miyazawa, Tazawa, 1996][by Miyazawa, Tazawa, 1996]

LPC has lower autogenous shrinkage and resultant-induced stressLPC has lower autogenous shrinkage and resultant-induced stress

Influence of mineral compositions of Influence of mineral compositions of cement cement on autogenous shrinkage on autogenous shrinkage

Mineral compositions of Portland cement in Mineral compositions of Portland cement in JapanJapan

Mineral content (%) Cement

C3S C2S C3A C4AF

OPC (Ordinary) 52 22 9 9

LPC (Belite-rich) 29 54 3 9

400x10-6

1000x10-6

High CHigh C22S, Low CS, Low C33AA

Calculated value

Basic equation; JSCE Code equation for AS

}])tt(aexp{1[')t,t(' bisasisas

)}C/W(2.7exp{3070'as

End valueDevelopment propertya=0.6, b=0.5 for W/C=0.3

Initial set

22Prediction model for autogenous shrinkage/expansion Prediction model for autogenous shrinkage/expansion strain, considered effect of EX and/or SRA strain, considered effect of EX and/or SRA

Approach for investigating prediction equation;Approach for investigating prediction equation; SRA effect -- Reduction of end value of ASSRA effect -- Reduction of end value of AS EX effect – Superposition of compensation of AS and AS of EX effect – Superposition of compensation of AS and AS of reference HSC based on JSCE-code equationreference HSC based on JSCE-code equation EX+SRA effect –Superposition of compensation of AS for EX+SRA effect –Superposition of compensation of AS for EX+SRA-added HSC, including synergistic effect , and AS of EX+SRA-added HSC, including synergistic effect , and AS of SRA-added HSCSRA-added HSC