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"Greening" the cementGreening the cement

A. Katz1, A. Bentur1, R. Cohen2

1National Building Research Institute1National Building Research InstituteTechnion – Israel Institute of Technology

2Nesher Israel Cement Enterprises LTD

▼▼

Objective

Investigation of composite cements, in order to increase their use in local conditionsto increase their use in local conditionsEffect on the properties of fresh concrete

– Setting time, bleeding, early age strength, sensitivity to g g y g g yplastic shrinkage, etc.

•Effect on standard properties at 28 daysEff t d bilit•Effect on durability

– Carbonation, chlorides penetration, volume changes (shrinkage)( g )

The motivation

Kyoto scenario

Projectionsj

29% reduction needed240 MT “ ” b 2010240 MT “gap” by 2010

More motivation

The highest motivation

CO2 emission from cement with various levels of slag replacementg p

CO2 Emissions

0 91.0

em

0.30

0.07

0.060.60.70.80.9

n in

2/ t

ce

0.500 34

0.21

0.140.05

0 040 20.30.40.5

k Em

issi

on

0.34 0.240.110.060.04

0.00.10.2

CEM I 32.5(OPC)

CEM II / B-S 30% l

CEM III / A 50% l

CEM III / B 75% l

Spec

ifi

(OPC) 30% slag 50% slag 75% slag

Calcination Thermal Electricity

Slag market (US Geological Survey, USGS)Slag market (US Geological Survey, USGS)

7The higher price in 2002-05 represents more complete data on l f d l t d bl t f l hi h ld fsales of ground granulated blast furnace slag, which sold for

almost $60 per ton, as opposed to air-cooled blast furnace and steel slags, which sold, on average, in the range of about $4 to

U.S. Geological

$7 per ton.

gSurvey – Slag 2008

Research program

F i f i dFour series of mixes were prepared:• Concrete containing cement only• Concrete containing cement + water reducingConcrete containing cement + water reducing

admixture• Concrete containing cement + fly-ash• Concrete containing cement + water reducing

admixture + fly-ashIn each series, AV mix was prepared first, and the otherIn each series, AV mix was prepared first, and the other

mixes were prepare using the same mix composition with different cements.

• Total 4 mixes X 3¼ types of cement X 3 curingTotal 4 mixes X 3¼ types of cement X 3 curing regimes

• 50 cubes, 16 beams and 6 cylinders for each mix

Type of cements

• The following cements were investigated:– CEM II/B-M(L-V) containing ~15% limestone, ~15% fly-ash (and ( ) g , y (

minor slag, ~5%) 65% clinker

– CEM II/B-M(S-L-V) containing ~11% slag, ~11% limestone and ~11% fly-ash ~65% clinker

• The cements were compared with cement containing ~12% fl h (AV)fly ash (AV)

• Some properties in one mix only were compared with CEM I ( 95% li k )(~95% clinker)

Properties of cements

Type of cement

Setting time (min)

Specific surface

Density Strength (MPa)cement (min) surface

area(cm2/gr.)

initial final 2 days 28 days

AV 280 360 3710 3 02 25 7 61 0AV 280 360 3710 3.02 25.7 61.0

MB(L-V) 110 190 4510 2.91 26.8 57.0

BM(S-L-V) 120 200 4351 2.95 25.7 58.2

Mix compositionComposition (kg/m3)

Mix No.

Mix design-

ation

Composition (kg/m3)

W/CcoarseCrushed sand Filler

Nat. sand Fly-ash Cement Water

WR admixtu

re

1 AV 835 692 81 228 ─ 304 204 ─ 0.67

2 LV 833 691 81 228 ─ 303 203 ─ 0.67

3 SLV 838 695 82 229 ─ 305 205 ─ 0.67

4 AV-S* 832 690 81 304 ─ 273 183 1.94 0.67

5 LV-S* 832 690 81 304 ─ 273 183 1.91 0.67

6 SLV-S* 832 690 81 303 ─ 273 183 1.91 0.67

7 AV-F 844 700 82 150 82 287 206 ─ 0.721

8 LV-F 834 692 81 149 81 283 204 ─ 0.721

9 SLV-F 834 692 81 149 81 283 204 ─ 0.721

10 AV-S-F* 836 694 82 225 82 254 184 1.78 0.721

11 AV-S-F** 835 692 81 219 81 253 183 4.55 0.721

12 LV-S-F** 829 688 81 218 81 252 182 4.53 0.721

1 Water to cement only, not considering the fly-ash. Fly-ash efficiency is 0.25 as determined in early experiments

13 SLV-S-F** 833 684 81 219 81 253 183 4.55 0.721

14 CEM I 827 686 81 226 ─ 301 202 ─ 0.67

Results:

Fresh concrete

Slump

160

180

200

120

140

160

היעקש

m)

60

80

100

מ''מ

,ה

Slum

p (m

m

0

20

40

V V V * * * F F F * * * * I

S

AV

LV

SL

V

AV

-S*

LV

-S*

SL

V-S

*

AV

-F

LV

-F

SL

V-F

AV

-S-F

*

AV

-S-F

**

LV

-S-F

**

SL

V-S

-F**

CE

M I

Bleeding5

3 5

4

4.5

שפרה

g/m

2 )

2

2.5

3

3.5

''ק

,םמי

ת ש

leed

ing

(kg

1

1.5

2

ר ''מ לג

Tota

l bl

0

0.5

AV

LV

SL

V

AV

-S*

LV

-S*

LV

-S*

AV

-F

LV

-F

SL

V-F

V-S

-F*

-S-F

**

-S-F

**

-S-F

**

CE

M I

A L

SL S

AV

AV

-

LV

-

SL

V- C

Bleeding rate exhibited similar trends

Setting timeSetting time

20

22

24

26

- זמן תחילת התקשרות

s)

Initial

14

16

18

20

שקתה

י מנז

עוש

)

- זמן סוף התקשרות

ime

(hou

rs Final

6

8

10

12

ן,טו בתרו ת)ו

Sett

ing

ti

0

2

4

6

AV

LV

SL

V

AV

-S*

LV

-S*

SL

V-S

*

AV

-F

LV

-F

SL

V-F

AV

-S-F

*

AV

-S-F

**

LV

-S-F

**

SL

V-S

-F**

CE

M I

Results:

Hardened concrete

Compressive strength

40

45

50

חו

יום 1

Pa)

day

25

30

35

יצחבל

ק וז

ימים 3

7 enימיםgt

h (M

P

days

days

15

20

25

ס ''פמג

,הצ 7 ימים

ימים 28

ress

ive

stre days

days

0

5

10

V V V * F F F * * * * I

ס

Cימים 90om

p

days

AV

LV

SL

V

AV

-S*

LV

-S*

SL

V-S

*

AV

- F

LV

-F

SL

V-F

AV

-S-F

*

AV

-S-F

**

LV

-S-F

**

SL

V-S

-F**

CE

M I

Effect of curing regime on compressive

1 04

Effect of curing regime on compressive strength

1

1.02

1.04תוספת מפחית

מיםתוספת אפר פחם תוספת אפר פחם

ומפחית מיםCement Cement + WR

admixtureCement + fly-

ashCement + fly-ash + WR admixture

0.98

1.00

ngth

0.94

0.96

סיח יקוזח

Rel

ativ

e st

ren

0.90

0.92

Water, 7 days

Spray, 3 daysSpray, 6 days

R

0.86

0.88

AV*AV AV AV*LV LV* LV LV**SLV AV**SLV*SLV SLV**

Flexural strengths

11.00

12.00

ח

ימים 28 daysימים 90 days

9.00

10.00

יפפבכ

ק וזח

ngth

(MPa

)

7.00

8.00

ס ''פמג

,הפ

exur

al st

ren

5.00

6.00

V V V S* * * F F F F* ** ** ** I

סFl

e

AV

LV

SL

V

AV

-S

LV

-S

SL

V-S

AV

- F

LV

-F

SL

V-F

AV

-S-F

AV

-S-F

*

LV

-S-F

*

SL

V-S

-F*

CE

M

Splitting strengths

6.00

7.00

חו

ימים 28 ימים 90

Pa)

days days

5.00

היעקבב

ק וז

reng

th (M

P

3 00

4.00

ס ''פמג

,ה

plitt

ing

str

2.00

3.00

AV

LV

LV

-S*

-S*

-S*

-F -F -F -F*

F**

F**

F**

M I

sp

A L

SL

AV

-

LV

-

SL

V-

AV

LV

SL

V

AV

-S-

AV

-S-F

LV

-S-F

SL

V-S

-F

CE

M

Carbonation, standard curing 40

30

35

40

קמעו

טבעי 90 ימים

מואצת 2 ימים

m)מואצת 4 ימיםm

)

20

25

הציונרבק

ק מואצת 7 ימים


tioמואצת 21 ימיםn

dept

h

5

10

15

מ ''מ

,ה



ימים 49 מואצת

Car

bona

t

0

5

AV

LV

SL

V

V-S

*

V-S

*

V-S

*

AV

-F

LV

-F

LV

-F

S-F

*

S-F

**

S-F

**

EM

I

ם מ 49 מואצת


S

AV

LV

SL

V A L

SL

AV

-

LV

-S

SL

V-S C

E

Carbonation- effect of curing

5

1.50

1.55

1.60

תוספת מפחית מים

תוספת אפר פחם תוספת אפר פחם Cementומפחית מים Cement + WR

admixtureCement + fly-

ashCement + fly-ash + WR admixture

Water, 7 days

1.30

1.35

1.40

1.45

מboעו

natio

n h

Spray, 3 daysSpray, 6 days

1.15

1.20

1.25

1.30

סח יהציונרבק

ק

elat

ive

carb

dept

h

1.00

1.05

1.10

Rסיe

0.85

0.90

0.95

AV*AV AVLV LV* LV LV**SLV AV*SLV*SLV SLV**

Chlorides transmission

14000

15500

17000

חד A אשפרהon,

Water, 7 days

11000

12500

14000

רלולכ

ת רודי

B trאשפרהan

smis

sio

ulom

b

7 days

Spray

6500

8000

9500

לוקו

,םדירי B אשפרה

Chl

orid

es t

cou Spray

3 days

3500

5000

6500

AV

LV

LV

-S*

-S*

-S*

V-F

V-F

V-F -F

*

F**

F**

M I

ון C אשפרה

C

Spray6 days

A L

SL

AV

-

LV

-

SL

V-

AV

LV

SL

V

AV

-S-

LV

-S-F

SL

V-S

-F

CE

M

2 20

Chlorides transmission-effect of curing

1.90

2.00

2.10

2.20


תוספת אפר פחם תוספת אפר פחם ומפחית מים

ion

Water 7 days

Cement Cement + WR admixture

Cement + fly-ash

Cement + fly-ash + WR admixture

1.60

1.70

1.80

לכת רודיח

tran

smis

si Water, 7 days

Spray, 3 days

Spray, 6 days

1 20

1.30

1.40

1.50

תסיח יםדירילוכ

chlo

ride

s t

0.90

1.00

1.10

1.20

Rel

ativ

e

0.80AV*AV AV AV*LV LV* LV LV**SLVSLV*SLV SLV**

Drying shrinkage

*

0A

V

LV

SL

V

AV

-S*

LV

-S*

SL

V-S

*

AV

-F

LV

-F

SL

V-F

AV

-S-F

*

AV

-S-F

**

LV

-S-F

**

SL

V-S

-F**

CE

M-I

-200

-100

0

geה

-400

-300

200

6 ת*קומטהצ

shri

nkag

-600

-500

400

10-6

C fl

-700

600

יום אחרי יציקה עד גיל 7 יום במים


תוספת אפר פחם תוספת אפר פחםומפחית מים

1 day after cast 7 days in water after cast

Cement Cement + WR admixture

Cement + fly-ash

Cement + fly-ash + WR admixture

Conclusions

• Larger surface area of the blended cement led to increased water demand or reduced slump. This could be controlled by proper use of water reducing admixtures.

• Setting time of the blended cement was shorter, but not as much as seen of the neat

t tcement paste.• Bleeding has reduced with the use of the

bl d d tblended cements

Conclusions (cont.)

• The compressive strength of concretes with blended cements was somewhat lower. Mainly b e ded ce e ts was so ew at owe . a ywhen fly-ash was used.

• One day compressive strength was quite similar with all concretes, except for concretes with fly-ash and WR admixture.

• Tensile strength was sensitive to mixes• Tensile strength was sensitive to mixes containing fly-ash and WR admixture. 90 days tensile strength improved in the presence of the blended cements.

Conclusions (cont.)

• Carbonation rate of concretes with blended t l LV tcements was larger. LV cement was more

sensitive.• Chloride penetration decreased in

concretes containing blended cements

Conclusions (cont.)

• Proper adaptation of the admixtures to the h i l d h i l ti f thchemical and physical properties of the

cements is of special importance for their ffi i t i tefficient use in concrete.

Disclaimer: the above mentioned conclusions are applicable to the cements tested in this study only.

ThankThank youy

HaifaHaifa

technion – israel institute of technology nesher israel...

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