Equivalent Performance with Half the Clinker Content · PDF fileEquivalent Performance with Half the Clinker Content using PLC and SCMClinker Content using PLC and SCM ... CaO•SO

2010 Concrete Sustainability Conference 1 © National Ready Mixed Concrete Association

Equivalent Performance with Half the Clinker Content using PLC and SCMClinker Content using PLC and SCM

Michael ThomasUniversity of New Brunswick

Kevin Cail, Bruce Blair, Anik Delagrave & Laurent BarceloLafarge North America

NRMCA Concrete Sustainability Conference. Tempe, Arizona, April 13-15, 2010


CaCO3 (limestonelimestone)

Portland Cement ManufacturePortland Cement Manufacture

Calcination: CaCO3 → CaO + CO2CaCO3 (limestonelimestone)2SiO2•Al2O3 (clay, shale)Fe2O3 (iron oxide)SiO2 (silica sand)

CO2

3 2~ 0.50 ton CO2 per1.0 ton of clinker

SiO2 (silica sand)

HeatHeat

Fuel: ~ 0.25 to 0.65 ton CO2per ton of clinker

Kiln

HeatHeat

3CaO•SiO2

2CaO•SiO2

3CaO•Al2O3ClinkerGypsum +

CaO•SO3•2H2O

3

4CaO•Al2O3•Fe2O3intergroundFinished

cement


CaCO3 (limestone)

Portland Portland LimestoneLimestone Cement ManufactureCement Manufacture

Calcination: CaCO3 → CaO + CO2CaCO3 (limestone)2SiO2•Al2O3 (clay, shale)Fe2O3 (iron oxide)SiO2 (silica sand)

CO2

3 2~ 0.50 ton CO2 per1.0 ton of clinker

SiO2 (silica sand)

HeatHeat

Fuel: ~ 0.25 to 0.65 ton CO2per ton of clinker

Kiln

HeatHeat

3CaO•SiO2

2CaO•SiO2

3CaO•Al2O3ClinkerGypsum +

CaSO4•2H2O

Limestone +CaCO3

3

4CaO•Al2O3•Fe2O3intergroundFinished

cement


Cement production accounts for approximately 7% to 8% of CO2 globally

(Mehta, 1998) …

d i l 2 8% f CO i i i C d ( i 199 )… and approximately 2.8% of CO2 emissions in Canada (Neitzert, 1997)

60%Calcination: CaCO3 → CaO + CO2 ↑ (gas)

Energy: C + O2 → CO2 ↑ (gas) 40%

www.cement.ca


PLC - Historical Timeline

ditio

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ow 5

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Typ

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in C

EM

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ent i

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ards

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%) i

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erm

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s up

to 5

n C

anad

a (e

x

20%

lim

esto

Fren

ch S

tan

Can

adia

n S

15%

(+/-

5%

Up

to 2

0% i

Up

to 2

0% i

Up

to 5

% in

AST

M C

15

AA

SHTO

al

Up

to 1

5% i

1965 1975 1983 1990 1992 2000 2003 2005 2007 2008


Cement types commercialized in Europe (according to Cembureau)


Cements Produced in Europe in 2004 (according to Cembureau)

P tl d li t t th j t t• Portland limestone cement was the major cement type produced in Europe in 2004


CSA A3001-08 Types of Hydraulic Cement Permitted

CSA A23 09 Use of Portland Cement in Concrete

PLC is produced to provide equivalent performance to PC in CanadaSo requirements for Type GUL (up to 15% limestone) same as Type GU (< 5%)

CSA A23-09 Use of Portland Cement in Concrete

• Portland limestone cement is permitted for use in all classes of concrete except for sulfate exposure classes (S-1, S-2, S-3)


CSA A3001-08 Requirements for Portland Limestone Cement

Composition [% per mass] L.O.I.

limit [%]Clinker Limestone

Limestone Cement

85 15 10Limestone requirements:• CaCO3 ≥ 75% (calculated from CaO)

• Clay ≤ 1.20/100g (determined by methylene blue test)

• Total organic carbon: TOC ≤ 0.50% by mass


Beneficial Effects of Limestone AdditionBeneficial Effects of Limestone Addition

• Limestone (primarily CaCO3) chemically reacts with C3A to form carboaluminates—at least at replacements of 5-10%

xhydration HCCACxHCCAC ⋅⋅⎯⎯⎯ →⎯++ 33

Tri-calciumaluminate

Intergroundlimestone

Calcium monocarboaluminate

Limestone is not totally inert !

• Finer limestone particles fill the voids between clinker particles improving the grain packing of cement

in clinkerlimestone (a.k.a. monocarbonate)

particles improving the grain packing of cement

• Fine limestone particles as nucleation sites for hydration products at early hydration ages accelerating the hydration and consequently improving the early strength


CaSO4gypsum+ CSH + CH + FH3 + pore solutionpore solution

ettringite

thaumasite

Reducedmonosulfate

Ms-ss

Reduced porosity

Increased porosity

C4AH13

calcite

MonocarbonateHemicarbonateC3A CaCO3

calcite

Hertford, 2008


Hawkins, 1986Effect of Limestone on Strength

Four cements with “constant” Blaine Four cements with “constant” < 325 mesh

L/stone (%) 0 2 5 8

Blaine (m2/kg) 371 351 346 364

L/stone (%) 0 2 5 8

Blaine (m2/kg) 390 387 433 470

< 325 (%) 90.0 85.5 81.0 82.4 < 325 (%) 94.7 91.9 91.2 91.6

40

50

Pa)

. 50

Pa)

.

20

30

40

Stre

ngth

(MP

0%

30

40

e St

reng

th (M

P

0%

0

10

20

Com

pres

sive 0%

3%5%8%

0

10

20

Com

pres

sive 0%

3%5%8%

01 3 7 28 91 182 365

Age (Days)

01 3 7 28 91 182 365

Age (Days)


50W/CM = 0.49 - 0.51

Effect of Fineness on Performance

6000

30

40 Com

presgth

(MPa

)

1 day7 days28 d

4000

20

30

ssive Strengthress

ive

Stre

ng 28 days56 days

200010

h (psi)

Com

pr

00380 450 500 580

2

PC PLC with 12% LimestoneBlaine (m2/kg))

Testing in Canada indicates that the Blaine of PLC needs to be increased by approx 100 – 120 m2/kg compared with PC to obtain equivalent performance


Tests carried out with Canadian materials -2007• Portland-limestone cements (PLC) were produced in different grinding

i it ith i li k (C A f 4 5 t 12%) d li tcircuits with various clinkers (C3A from 4.5 to 12%) and limestones.

• Amount of limestone varied between 3 and 19% (to keep within limits, the real CSA PLC max. will be ~13%).

S d d d h i l l f d h• Standard mortar tests and chemical analyses were performed on the different PLCs.

• Concrete with various w/cm ratio’s 0.35 to 0.80 were produced. The cement contents in the mixed varied between 225 and 420 kg/m3cement contents in the mixed varied between 225 and 420 kg/m3

• Concrete tests with different PLC’s (10 to 22 %LS) and various amounts of slag (15, 25, 30%) and fly ash (20%) were performed

Sl l t ti d i d• Slump, slump retention and air were measured

• Durability tests were performed, e.g. RCP, freeze/thaw, salt scaling, shrinkage, sulfate resistance, and ASR

T ti d t d b t i d i iti• Testing conducted by cement companies and universities

• Concrete laboratory tests and field trials undertaken by one of the cement companies presented in this paper


Example Test Program Example Test Program –– Cement Company #2Cement Company #2

Total CementingMaterial

CementType

SCM Fresh properties & strength

Freeze-Thaw

DeicerSaltScaling

RCPT

240 kg/m3

(400 )

PCPLC-12%

0%X

(400 pcy)

355 kg/m3

(600 pcy)

PCPLC-12%

0%20% Fly Ash X X X X(600 pcy) Ash35% Slag

410 kg/m3

PCPLC-12%

0%X X X X

(700 pcy)


100

Fineness PLC vs. PCFineness PLC vs. PC

80

PLC60

sing

(%)

PC

PLC

20

40Pass

0

20To achieve equivalent performance PLC is ground to a higher fineness

1 10 100 1000

Particle Size (μm)


Fineness in PLC: Clinker vs. LimestoneFineness in PLC: Clinker vs. Limestone

80

100

Also clinker in PLC is ground finer than

60

ng (%

)

D50 Limestone:7 to 10 μm D50 Clinker: 15 μm

clinker in PC

40Pass

in μ D50 Clinker: 15 μm

0

20Limestone fineness in the intergroundproduct is significantly finer than the clinker fraction

1 10 100 1000

Particle Size (μm)


Company 2: Time of Set, w/cm = 0.45Company 2: Time of Set, w/cm = 0.45

ASTM C403 Set Time (hr:min)PC0 5:40PC12 4:50PC12 4:50

PC0+20% FA 6:20PC12+20%FA 5:45

PC0+35% Slag 7:05PC12+35% Slag 5:45g

• Slumps: 100-120 mm

• Air: 5.3-6.0 %

• Only mix with measurable bleeding = PC0


Company 2 Second Test Grind – Strength Results – w/cm = 0.40 & 0.80 (no SCM)

10000

800060

Co

MPa

)

W/CM = 0.40

600040

mpressive SSt

reng

th (M

PC

PLC

4000

20

Strength (psiompr

essiv

e

W/CM = 0.78 - 0.80

0

2000

0

i)C

o

000 14 28 42 56

Age (days)


Company 2 Second Test Grind – Strength Results – w/cm = 0.45 & SCM

40

)

Strength at 1 day Strength at 7 days

20Stre

ngth

(MPa

)

PC

PLC - 12%

3000

4000

5000

Com

pressive 20

Com

pres

sive

S

1000

2000

3000 Strength (psi)

0No SCM 35% Slag 20% Fly Ash

C

Supplementary Cement Materials

0No SCM 35% Slag 20% Fly Ash



Company 2 Second Test Grind – Strength Results – w/cm = 0.45 & SCM

Strength at 28 days Strength at 56 days60

a)

7000

8000

40

Stre

ngth

(MPa

5000

6000

Com

pressive

20

Com

pres

sive

S

2000

3000

4000

Strength (psi)

0

C

0

1000

2000

No SCM 35% Slag 20% Fly Ash


No SCM 35% Slag 20% Fly AshSupplementary Cement Materials


Company 2 Second Test Grind – Durability Tests – w/cm = 0.40, 0.45 & SCM

100

Freeze-Thaw Resistance (ASTM C 666)600

Scaling Resistance (ASTM C 672)

PC

40

60

80

ura

bili

ty F

acto

r

PCPLC - 12%

200

400

Mas

s Lo

ss (

g/m

2 )

PC

PLC - 12%

0

20

No SCM (0.40)

No SCM (0.45)

35% Slag (0.45)

25% Fly Ash (0.45)

Du

Supplementary Cementing Materials (w/cm)

PLC 12%

0

No SCM (0.40)

No SCM (0.45)

35% Slag (0.45)

25% Fly Ash (0.45)

M

Supplementary Cement Materials (w/cm)Supplementary Cementing Materials (w/cm) Supplementary Cement Materials (w/cm)

3000

ulo

mbs

)

Chloride Permeability at 28 days

PCPLC - 12%

3000

lom

bs)

Chloride Permeability at 56 days

PCPLC 12%

1000

2000

har

ge P

asse

d (C

ou PLC - 12%

1000

2000

Ch

arge

Pas

sed

(Co

u PLC - 12%

0

No SCM (0.40)

No SCM (0.45)

35% Slag (0.45)

25% Fly Ash (0.45)

Ch

Supplementary Cement Materials (w/cm)

0

No SCM (0.40)

No SCM (0.45)

35% Slag (0.45)

25% Fly Ash (0.45)

C

Supplementary Cement Materials (w/cm)


Company 2 Second Test Grind – Durability Tests – ASR & Sulfate Resistance

0.4ASR Testing

1 2Sulfate Resistance Testing

0.3

0.4

n (%

)

PC

PLC0 8

1.0

1.2

PC

PLC

0.2

Expa

nsio

n

0.6

0.8

Exp

ansi

on (%

)

0

0.1

0.2

0.4EAMBT CPT ACPT

Test (age when expansion reported)

(14 days) (1 Year) (3 months)

0.00 3 6 9 12

Age (days)

AMBTCPTACPT

Accelerated Mortar Bar Test, ASTM C 1260Concrete Prism Test, ASTM C 1293Accelerated Concrete Prism Test

ASTM C 1012 Mortar bars immersed in 5% Na2SO4 solution


Field TrialsField Trials

Brookfield Cement Plant NSExshaw Cement Plant, AB

Brookfield Cement Plant, NS

Gatineau Concrete Plant, QC


PLC Trial Pour at Gatineau ReadyPLC Trial Pour at Gatineau Ready--Mixed Concrete Plant Mixed Concrete Plant –– October 6, 2008 October 6, 2008

Objective:

• Field test performance of PLC concrete with• Field test performance of PLC concrete with various levels of SCM in an exterior flatwork application.

• Control sections with Type GU + SCM

Cement SCM Replacement Level (%)0 25 40 50

Eight Concrete Mixes:

0 25 40 50

Type GU X X X X

Type GUL X X X X

• Type GU with 3.5% limestone (PC)

Cementing Materials:

• Type GUL with 12% Limestone (PLC)

• Blended SCM = 2/3 Slag + 1/3 Fly Ash



Objective:

• Field test performance of PLC concrete with• Field test performance of PLC concrete with various levels of SCM in an exterior flatwork application.

• Control sections with Type GU + SCM

Cement SCM Replacement Level (%)0 25 40 50

Eight Concrete Mixes:

0 25 40 50

Type GU 92 69 55 46

Type GUL 84 63 50 42

• Type GU with 3.5% limestone (PC)

Cementing Materials:

Clinker content (% of total cementitious)

• Type GUL with 12% Limestone (PLC)

• Blended SCM = 2/3 Slag + 1/3 Fly Ash



Fresh concrete properties:• SlumpSlump• Air• Temperature• Density

Hardened concrete properties on site-cast specimens:• Strength• RCPT• Hardened Air-Void Parameters• Freeze-thaw (ASTM C 666: Proc. A)• Salt Scaling (ASTM C 672 & BNQ Method)

Properties of 35-Day-Old Cores:• Strength• RCPT

Chl id diff i ffi i• Chloride diffusion coefficient



Properties of Plastic Concrete

SCM (%)

Cement Type

W/CMSlump (mm)

Air (%)Temp (°C)

Unit Wt. (kg/m3)

Properties of Plastic Concrete

0 PC 0.45 100 6.8 18.8 2317PLC 0.44 80 6.0 17.5 -

25 PC 0 44 75 6 2 18 1 231725 PC 0.44 75 6.2 18.1 2317PLC 0.45 100 6.6 16.3 2328

40 PC 0.44 95 6.8 16.5 2303PLC 0 44 80 6 0 15 5 2331PLC 0.44 80 6.0 15.5 2331

50 PC 0.44 95 6.8 15.0 2300PLC 0.44 95 6.5 14.5 2309



Vibrating Screed Bullfloat

Broom Finish Insulated Tarps (except slab 5)


PLC Trial Pour PLC Trial Pour –– Cylinder StrengthsCylinder Strengths

30 2 29 8 30 330 5 29 6 31 1

40 7-Day Strength

24.221.7

18.915.3

25.220.7 19.2

15.6

10

20

30

gth

(MPa

)

3-Day Strength PCPLC

30.2 29.8 30.3 29.430.5 29.6 31.128.8

10

20

30

Stre

ngth

(MPa

)

0

10

0% SCM 25% SCM 40% SCM 50% SCM

Stre

ng

0

10


37.741.3

43.5 43.038.2 39.8

43.5 42.5

40

50 28-Day Strength41.3

45.448.6 48.7

40.944.7

48.3 46.5

40

50

60

MPa

)

56-Day StrengthPC

PLC

20

30

Stre

ngth

(MPa

)

20

30St

reng

th (M

0

10

0% SCM 25% SCM 40% SCM 50% SCM0

10



PLC Trial Pour PLC Trial Pour –– Core Strengths at 35 DaysCore Strengths at 35 Days

39.735.7

42.337.6

35.3 35.5

43.239.4

40

50 PCPLC

Core Strength

20

30

treng

th (M

Pa)

0

10

St

00% SCM 25% SCM 40% SCM 50% SCM


PLC Trial Pour PLC Trial Pour –– RCPT ResultsRCPT Results

3000

4000m

bs)

PC at 28 days

PLC at 28 days

2000

3000

ssed

(Cou

lom

PC at 56 days

PLC at 56 days

1000

Cha

rge P

as

28d

56d

00 10 20 30 40 50 60

SCM Replacement Level (%)

56d

SCM Replacement Level (%)


RCPT Results for Cores taken at 35 DaysRCPT Results for Cores taken at 35 Days

Charge Passed in 6 Hours (CoulombsCement

Charge Passed in 6 Hours (Coulombs0% SCM 25% SCM 40% SCM 50% SCM

PC 2395 1410 570 491PLC 2345 1308 617 520

Chloride Diffusion Coefficients Determined on Cores taken at 35 DaysChloride Diffusion Coefficients Determined on Cores taken at 35 Days

Charge Passed in 6 Hours (CoulombsCement

Charge Passed in 6 Hours (Coulombs0% SCM 25% SCM 40% SCM 50% SCM

PC 15.0 3.77 1.51 1.25PLC 11.9 2.91 1.22 1.81


Chloride Profiles for Cores taken at 35 DaysChloride Profiles for Cores taken at 35 Days

and Immersed in and Immersed in NaClNaCl for 42 Daysfor 42 Days

1.0

1.2re

te) PC - 0% SCM

PLC - 0% SCM

0 6

0.8

mas

s of

conc

PLC 0% SCM

PC - 25% SCM

PLC - 25% SCM

0.4

0.6

ide (

% b

y m PC - 50% SCM

PLC - 50% SCM

0.0

0.2

Chl

ori

0 5 10 15Depth (mm)


PLC Trial Pour PLC Trial Pour –– Scaling Test ResultsScaling Test Results

497600

m2 ) BNQ Test Method

273

380

497

400

Mas

s Los

s (g

/mPCPLC

Q

39106114 127 142

0

200

Scal

ed M

0

400400

600

s (g

/m2 )

PC

ASTM C 672

80

230

320

200

400

aled

Mas

s Los

s PCPLC

40 3080

1050

00% SCM 25% SCM 40% SCM 50% SCM

Sca


PLC Trial Pour PLC Trial Pour –– Other Test ResultsOther Test Results

SCM (%)Cement

Type

Air-Void ParametersDurability Factor (%)Type Factor (%)

Air (%) L (mm)

0PC 5.3 173 101

0PLC 5.6 187 100

25PC 4.9 148 101

PLC 5.4 149 104

40PC 5.6 164 101

PLC 5.3 165 103

50PC 5.6 150 102

50PLC 6.6 147 100


April 2, 2009


PLC + 25% SCMApril 2, 2009

PLC + 50% SCM

PC + 25% SCM

PC + 50% SCM


PLC Trial Pour PLC Trial Pour –– ConclusionsConclusions

• No observable differences between plastic properties, placing and finishing of concrete with PC or PLC at a given level of SCM

• No significant difference between strength and permeability ofNo significant difference between strength and permeability of concrete with PC or PLC at a given level of SCM

• No consistent trends in salt scaling resistance of PC concrete compared with PLC concrete at a given level of SCM

• Long-term strength and permeability improved as level of SCM increased

• Resistance to salt scaling reduced as SCM level increased, gespecially at 50% SCM


Exshaw Cement Plant, Alberta• Sept 2009p

• Paving, Curbs & pumped concrete

• PC & PLC cements

• 15, 25 & 30% fly ash, y


Brookfield Cement Plant,Nova Scotia

O t 2009• Oct 2009

• Paving

• Blended PC & PLC cements containing 15% slag% g

• 15 & 20% fly ash


Field Trials Field Trials -- 20092009Exshaw Cement Plant, Alberta Brookfield Cement Plant, Nova Scotia

000

25

304000

5000 Com

pressiv

11 d

ays (

psi) PC PLC

20

25

3000

Com

pressi3 da

ys (p

si) PC-Slag PLC-Slag

15

20

2000

3000

ve Strength at 1

ve S

treng

th at

1

10

152000

ive Strength at ve S

treng

th at

3

5

101000

1 days (MPa)C

ompr

essiv

51000

3 days (MPa)

Com

pres

si

000% Fly

Ash15% Fly

Ash25% Fly

Ash30% Fly

Ash

000% Fly Ash 15% Fly

Ash25% Fly

Ash

Specimens cast from both sites for laboratory testing:

• Strength• Salt Scaling• Chloride Permeability


PLC Trial Pour at Gatineau Ready-Mixed Concrete Plant – October, 2008

CO2 Reductions

• 355 kg/m3 (590 pcy) cementing materials

• Type GU with no SCM - 92% clinker in cementing material

Type GUL with 40 to 50% SCM 50 to 42% clinker in cementing material• Type GUL with 40 to 50% SCM – 50 to 42% clinker in cementing material

• CO2 reduced by approx 1 tonne per 6-m3 truck (1 ton per 8-yd3 truck)

• But can’t use 40 – 50% SCM in every application

• Type GUL with 25% SCM – 63% clinker in cementing material

• CO2 reduced by approx ¾ tonne per 6-m3 truck (¾ ton per 8-yd3 truck)


Brookfield Cement Plant, Nova Scotia

• 386 kg/m3 (643 pcy) cementing materials

• Type GU - 91% clinker in cementing material

• Type GULb (15% slag + 12% limestone) – 68% clinker

• CO2 reduced by approx ½ tonne per 6-m3 truck (½ ton per 8-yd3 truck)

• Type GULb can be used as a base cement for nearly all cases – with further incorporation of SCM at the concrete plant depending on the application

Type GU CementGypsum

Limestone

Type GULb Cement

68% Clinker92% Clinker

Limestone

Gypsum

Limestone

SlagApprox 25% reduction inclinker (& CO2 emissions)


Overall Summary Overall Summary

• Portland limestone cements with up to 15% limestone when• Portland-limestone cements with up to 15% limestone, when optimized for equal early-age strength, can be used in concrete together with fly ash and slag at the levels typically added at the concrete plantadded at the concrete plant.

• Optimization of PLC requires higher Blaine fineness to get equal grinding of the harder clinker fraction.

• Canadian Standards now permit the use of portland limestone cements with up to 15% interground limestone

• This provides an opportunity to reduce in CO2 emissions by ~This provides an opportunity to reduce in CO2 emissions by 10%, while providing similar technical performance to current GU cements.

• PLC performs well with normal levels of slag or fly ash• PLC performs well with normal levels of slag or fly ash replacements (providing further opportunities to reduce CO2emissions)


Questions?Questions?Questions?Questions?

Documents

Equivalent Performance with Half the Clinker Content · PDF fileEquivalent Performance with Half the Clinker Content using PLC and SCMClinker Content using PLC and SCM ... CaO•SO