Conceptual cement for environmental and durability

requirementsrequirements

Kazuo YamadaR&D CenterR&D Center

Taiheiyo Cement Corp.

Conceptual cementConceptual cement• Conceptual cement

d ’ l i j d l id i– Today’s proposal is just under personal consideration. – There is no quantification for environmental impacts.– Sales persons in our company disagree with this kind of new cement!p p y g

• High C3A cement is really bad?– Why high C3A cement is important,– The method how we can improve the negative parts will be explained.

• A proposal to produce a new type of cementIt has to satisfy the requirements from environments– It has to satisfy the requirements from environments

– It must have at least standard performance as conventional cement including durability. It is nonsense, if the performance of new

i t l f i dl t i i f ienvironmental friendly cement is inferior.– This is a story of hybridization of our knowledge but not innovative.

Taiheiyo CementPlants and Blanches overseasPlants and Blanches overseas

T ih i P ifiTaiheiyo = Pacific ocean

California Portland CementTaiheiyo USA

•Japan (24 Mton/y, 37 %-share)•Abroad (24 Mton/y)

There is no need to think about localization of materials at least in this part of world.

Indispensable cement for buildings or road constructions.Our business is to supply materials to active societies.

W th A t i d tWe are the Artery industry

Enormous amount of wastes produced from active societies.Our business is to recycle them for the protection of environments.

Taiheiyo Cement Corp.

If I could live life over again I want to be a buildingIf I could live life over again, I want to be a building.Incinerator ash of municipal wastes treated as landfill comes back life again as cement.

Waste material managementg

• Cement industry has already been an indispensable C y y pprocess to accept significant amounts of wastes in the human society at least in Japan.

• Without cement industry, it is impossible to keep our life!

Example of Japan, 2004Remained capacity of final landfill site for industrial wastes: 184 Mm3Its remained life: 7 2 yIts remained life: 7.2 y Annual amount of industrial wastes: 25 Mm3/y Annual amount of wastes received by cement plants 20 Mm3/y Cement industry save almost half size of landfill site.

Waste Materials Used in Cement Industry kton/y

Item 2001 2002 2003 2004 2005 2006 2007f ( )

fiscal year

Blast furnace slag (mainly blended) 11,915 10,474 10,173 9,231 9,214 9,711 9,304Coal ash (mainly raw meal) 5,822 6,320 6,429 6,937 7,185 6,995 7,256Gypsum by-product 2,568 2,556 2,530 2,572 2,707 2,787 2,636Dirt, Sludge 2,235 2,286 2,413 2,659 2,526 2,965 3,175, g , , , , , , ,Soil f rom construc t ion 0 269 629 1,692 2,097 2,589 2,643Non-ferrous slag 1,236 1,039 1,143 1,305 1,318 1,098 1,028Unburned ash, soot, dust 943 874 953 1,110 1,189 982 1,173Molding sand 492 507 565 607 601 650 610Molding sand 492 507 565 607 601 650 610Steel manufacture slag 935 803 577 465 467 633 549Wood chips 20 149 271 305 340 372 319Waste plastic 171 211 255 283 302 365 408Coal tailing 574 522 390 297 280 203 155Recycled oil 204 252 238 236 228 249 279Waste oil 149 100 173 214 219 225 200Used t ire 284 253 230 221 194 163 148Used t ire 284 253 230 221 194 163 148Used clay 82 97 97 16 173 213 200Bone-meal feed 2 92 122 90 85 74 7Others 428 435 378 452 468 615 565Total 27,359 28,061 27,238 27,566 28,782 29,593 30,890 30,720Rat io: kg/ t -cement 332 355 361 375 401 400 423 436Cement production 82,407 79,045 75,451 73,504 71,771 73,931 73,931 70,600

Role of cement industryy• We are the Artery industry

– Binder in concrete– Corrosion inhibitor for steel reinforcement

• and also the Vein industry– Utilization of various and enormous solid wastes– Thermal recycle of combustible wastes

• under a control of environmental impacts– Less CO2 and hazardous materials emissions– Purification of pollutants such as dioxins and recovery

of heavy metals as resources

More wastes!

We have• Economical reasonEconomical reason.• Environmental reason.

Using more wastes result in higher Al2O3 contentSiO2

g g 2 3

● Portland cement◇ Crashed concrete powder○ Steel slag＊ Incinerator ash of urban waste

＊

＋

Incinerator ash of urban waste＋ Sewage sludge× Coal ash－ City water sludge

＊

＊

＊＊＋

Al2O3

＊

＊CaO

Typical example of high C3A cement: Japanese ecocementJapanese ecocement

• Ecocement: Portland cement but more than half is wastes origin.g

• It satisfies CEM I 42.4N by EN197-1:2000.• Compared with JIS, Cl content is over.

0.05% in ecocement vs. 0.035% by standard.• At present, two plants are in commercial

operation in large Tokyo area to produce around 250 kton/y.

Comparison of chemical and mineral compositions of ecocementof ecocement

compared to normal and low heat portland cements

ig.loss SiO2 Al2O3 Fe2O3 CaO SO3 Na2Oeq ClEC 0 3 17 0 8 0 4 4 61 0 3 7 0 26 0 053

TypeChemical Composition (％)

EC 0.3 17.0 8.0 4.4 61.0 3.7 0.26 0.053NPC 0.6 21.2 5.2 2.8 64.2 2.0 0.65 0.005LC 0.6 26.3 2.8 3.1 62.4 2.3 0.45 0.004

C3S C2S C3A C4AFType

Mineral Composition (％)3 2 3 4

EC 47 15 13 13NPC 59 15 8 9LC 31 53 3 8LC 31 53 3 8

Compressive Strength Development

100

120（M

Pa）

80

reng

th（

40

60

ssiv

e St

r

20

Com

pres NPC55 EC55

LHPC55 NPC30EC30 LHP30

00 20 40 60 80 100

Age （days）

C EC30 LHP30

Age （days）Strength development is acceptable.

Chloride ingress

8 50 N

gby immersion test in 3% NaCl solution

W /C =50%　20℃

6

8

/ye

ar)

50-N

50-E

2

4

Da(cm2/

0

0 10 20 30Tim e(m onths)Tim e(m onths)

Apparent diffusion coefficient of Cl is higher in ecocement than NPC.Problem is the no time reduction of Da for ecocement possibly dueProblem is the no time reduction of Da for ecocement, possibly due to the perfect hydration at early ages.

Sulfate attackASTM C1012, 5%Na2SO4

OPC

0.20

0.24

0.28

(%)

OPCSRPCSL

OPC: JapaneseSRPC: Canadian

0.12

0.16

Exp

ansi

on SL: Japanese 40% blast

furnace slag (Al2O3=15%)

0 00

0.04

0.08E High reactive alumina content is basically bad.Ecocement will be worse!0.00

0 20 40 60 80 100 120Immersion duration (weeks)

Ecocement will be worse!

Under a collaboration with Prof. D. Hooton

Conflicting requirements

• For durability– Lower C3A & C3SLower C3A & C3S

• For waste materials utilization• For waste materials utilization– More Al2O3

DurabilityW k bili li i d f d i l L C A?• Workability to eliminate defects during placement: Lower C3A? Ultra-high strength more than 100-200 MPa is only possible with low heat cement with low C3A.

• Hydration heat: Lower C3A? For mass concrete, belite-rich and low C3A cement is preferable.

• Early age strength development of cover concrete: Belite-rich cement or y g g pblended cement is questionable because of the lower early age strength.

• Crack by autogeneous and drying shrinkage?• Chloride ingress?Chloride ingress?• Sulfate attack: High Al slag is deteriorative?• Carbonation?• ASR: In Japan, it is better to assume every aggregate is reactive.• F/T• LeachingLeaching

Checking and proposing improvement!

Effects of Ca sulfate on fluidity for different C A contentdifferent C3A content

Mortar flow with polycarboxylateCli k

350

400

mm)

■ No.3 (0.70, 9.15, 19.34)

ClinkerSO3 (%)

250

300

flow (m

▲ NO.2 (0.96, 10.17, 19.29)● No.1 (1.25, 10.27, 19.30)

C3A (%)

150

200

Mortar C3A (%)

C3A+C4AF (%)

Adequate amount of Ca sulfate

100

1.8 2.0 2.2 2.4 2.6 2.8

qenable to enhance the fluidity even for high C3A cement.

SO3 in cement (%)

Chloride ingressW /C =50%　20℃

6

8

/ye

ar)

50-N

50-E W /C =40%　20℃3

4

/year)

40-N

40-E

0

2

4

Da(cm2/

0

1

2

Da(cm2/

0

0 10 20 30Tim e(m onths)

0

0 10 20 30Tim e(m onths)

4 50-NW /C =50%　20℃

2

3

4

2/year)

50 N50-L40%slag15%FA25%FA50%Sl FA

• Ecocement is inferior to NPC in relatively high W/C.

• Lowering W/C is one way

0

1

2

Da(cm2 50%Slag-FA • Lowering W/C is one way

to enhance the durability.• SCM addition is a very

0

0 10 20 30 40Tim e(m onths)

effective way to reduce Da.

Hydration heat60℃

）

Slag40%60℃）

Slag40%

30

40

50

emp rise（

Slag40%

EC OPC30

40

50

emp rise（

Slag40%

EC OPC

• Temperature rise of ecocement is slightly higher than OPC.

• Slag is not a good way to

0

10

20

30

diabatic te

0

10

20

30

diabatic te Slag is not a good way to

reduce temperature rise in hot climate.

• Other pozzolans such as fly ash00 2 4 6 8 10 12 14

Age (day)

Ad 0

0 2 4 6 8 10 12 14Age (day)

Ad • Other pozzolans such as fly ash

are indispensable.80

OPCBS40) 80OPCBS40) 80)

50

60

70BS70BS40+FA30

p rise (℃)

50

60

70BS70BS40+FA30

p rise (℃)

50

60

70

p rise (℃)

20

30

40

iabatic tem

Unit C：327kgPlacing T：20℃20

30

40

iabatic tem

Unit C：327kgPlacing T：20℃ 20

30

40

abatic temp

Unit C：327kgPlacing T：30℃

Age (day)

100 1 2 3 4 5

Adi

Age (day)

100 1 2 3 4 5

Adi

100 1 2 3 4 5

Adi

Age (day)

SCM seems indispensable• FA?

– Yes, it is effective to reduce hydration heat, ASR, sulfate & Cl attacks. But controlling the carbon content and reactivity is the problemBut controlling the carbon content and reactivity is the problem.

– Electricity company says “We are producing electricity but not fly ash. We can not pay much attention for the quality of wastes.”Wh t t k h d f h l t i it ?– Who want to work so hard for such electricity company?

• Blast furnace slag?– A specialist of Nippon steel says “If the blast furnace is designed byA specialist of Nippon steel says If the blast furnace is designed by

Japanese companies, it means the quality of slag is perfectly designed and controlled as SCM. Quality of slag is equal to that of steel”

– Every slag from various blast furnace has equivalent chemicalEvery slag from various blast furnace has equivalent chemical compositions and shows compatible strength developments and effectiveness for durability. But hydration heat and cracking resistance are the problems.

• Are there other candidates?

LSP 0%

Surprising effect of limestone

50

60

70

h (N

/mm2

)

28dLSP 0%LSP 5%

50

60

70

h (N

/mm2

)

7d

28dLSP-0%LSP-5%

30

40

sive

stre

ngt

3d

7d

30

40

ive

stre

ngth

3d

7d

0

10

20

Com

pres

s

1d

0

10

20

Com

pres

si

1d

00 20 40

BFS (%)

0 20 40BFS (%)

Base cement: OPC Base cement: Ecocement

Analysis of the effect of LS addition

60

N/m

m2 ) 28days

7days3d

7d

3d

0d MsEttCHC-S-H

OPC

OPC

40

ment Paste (N 3days

7d

3d

0d

28d

HcMcEttCH

LSP

C-S-H

OPC

C-LSP O

20

trength of Cem

7d

3d

0d

28d

7d

MsEttCHC-S-H

BFSOPC

-BFS OPC

OPC

-LSP

-BFS

-LSP

0

ompressive St

3d

0d

28d

7d

EttCHC-S-H

LSPBFSOPC

S-LSP OPC

OPC-

OPC-

OPC-B

FS-

Co

28d

7d

0 20 40 60

Mc Hc

Theoretical Volum e O ccupancy (Vol%)

OPC-BFS

XRD/Rietveld analysis with selective dissolution method

Mechanism is simple!80

/mm

2 ) OPCOPC -LSPOPC BB

60

ngth

(N

/ OPC -BBOPC -BB-LSP

40

ive

stre

n

20

ompr

ess

35 40 45 500

Co

Theoretical porosity by Rietveld method (%)

Effect of limestone addition onEffect of limestone addition on the optimum sulfate content

80 8080

● : NPS system ○ : LSP ● : NPS system ○ : LSP ● : NPS system ○ : LSP

40

60st

reng

th (M

Pa)

40

60

stren

gth

(MPa

)

40

60

stren

gth

(MPa

)

3.4

3.4

4.4

3.64 87day

28day7day

28day

7day

28day

20

40

Com

pres

sive

s

20

Com

pres

sive

20

40

Com

pres

sive

3.4

2.83.2

4.6

1da

3day

7day

1da

3day

1da

3day

y

01 2 3 4 5 6 7

SO3 cont ent (mass%)

01 2 3 4 5 6 7

SO3 content (mass%)

01 2 3 4 5 6 7

SO3 content (mass%)

C3A=2.5% C3A=8.8% C3A=12.5%3 C3A 8.8% 3

Impressive effect of LS for sulfate resistance

0.28 OPCSRPC

OPC: JapaneseSRPC: Canadian

p

0 16

0.20

0.24

ion

(%) SL

HSRSLC1SL: Japanese 40% blast furnace slag (Al2O3=15%)HSRSLC1: Modified SL by

0.08

0.12

0.16

Exp

ansi HSRSLC1: Modified SL by

several % addition.

Hi h ti l i t t

0.00

0.04

0 20 40 60 80 100 120

High reactive alumina content is basically bad.By the addition of small 0 20 40 60 80 100 120

Immersion duration (weeks) amount of calcite, it is possible to improve sulfate resistance drasticallyUnder a collaboration with Prof. D. HootonM ll i i hi i H Chi drastically.My colleague is presenting this in Ho Chi

Minh City this week at ACF conference.

Early strength enhancement by fine limestone

30h) 30h)

15

20

25

n ra

te (J

/g ・

0.3μmSL5%

0.3μmSL10%

202530

n ra

te (J

/g ・h

0.3μmSL5%

5

10

15

at e

volu

tion

Blank

51015

t evo

lutio

n

Blank

8μmLSP5%

OPC

00 10 20 30 40 50 60

Time (hr)

Hea 0

0 10 20 30 40 50 60Time (hr)

Hea

tOPC pasteW/C=0.30Polycarboxylate superplasticizer

( ) ( )

Fine calcite activate the early hydration of C3S.

For ASR: Siliceous shale

80.090.0

/mm

2 )

80.0

mm

2 )

40 050.060.070.0

stre

ngth

(N

50.060.070.0

reng

th (N

/m

10 020.030.040.0

mpr

essi

ve s NC no add

SF-5%SF-10%SF-20%

10 020.030.040.0

pres

sive

str

NC no addKw-2.5-5%Kw-2.5-10%Kw 2 5 20%

0.010.0

0 7 14 21 28Age (day)

Com

0.010.0

0 7 14 21 28Age (day)

Com

p Kw-2.5-20%

g ( y)

Close to silica fume!

Main component: Opal-CTHuge amount of resource. Some are used as silica source for cement production Close to silica fume!as silica source for cement production.Superplasticizer is required because of the large absorption caused by SSA 120m2/g.

Effect on ASR expansion0 60

0.50

0.60)

Highly reactive andesite aggregate.Kw: siliceous shale.

0.40

0.50

M C

1260

) Kw: siliceous shale.

0.30

(%, A

STM

0.20

pans

ion

(

K 2 50.10Exp Kw-2.5

Kw-8SFFA

0.000% 5% 10% 15% 20%

Replacement ratio

Proposal of new cement under the balance of requirements from environmental and

performance in concreteperformance in concrete

• High C3A cement base,• With the addition of

– Blast furnace slag,– Fine limestone,– and Siliceous shale.

• Calcite has a great function only for high alumina conditions.

d i i h f l• In order to optimize the formula….

Thermodynamic calculation will be a good way.OPC 40% slag Immersion into NaCl

250

500Cl－

OH－

[液相]

Na+ Cl－

Na+

OPC 40% slag

c. m

ol/m

3

1 5 Na KOPC 40% slag

Total amountImmersion into NaCl

0

250K+

Ca2+

0.6

OH－NaK+

Ca2+Ion

con

0.5

1

1.5

Cl

SO3

[全量] Cl

SO3lem

ent

mol

/kg-

cem

0.2

0.4

C4AH13

MsFr

[固相] C4AH13

Ms

Fr

Hyd

rate

sm

ol/k

g-ce

m

0 2 4 60

3

0 2 4 6

3

深さ(cm)

E m

0C4AH13

Ett

0.1

-SiO－ ①-SiONa ②-SiOK ③-SiOCa+ ④-SiOCaCl ⑤-SiOCaSO4

－

Ett

H m

0.6[OPC] [BB]Cl

EPMA Measurement（Same mix and immersion cond.）

m

0.05

0.1[CSH吸着]

①

②③④

⑤①

②

③④

⑤

ilano

l gro

upm

ol/k

g-ce

m

0

0.2

0.4 ClSO3

Na

[OPC] [BB]ClSO3

NaElem

ent

mol

/kg-

cem

0 2 4 60

①

0 2 4 6

①

Depth from the surface (cm)

Si m 0 2 4 60

0 2 4 6Depth(cm)

Conclusions

• We have to use Al2O3 rich waste in some way.• High C3A cement is a candidate.g 3• Combining slag, limestone, and siliceous

materials seems a reasonable solution for durable concrete material.

• Thermodynamic calculation will be an effective ytool to estimate the performance.

• Al behaviors in C-S-H is the next topic of study.p y