Decreasing the Clinker Component in CtiMtilCementing ...

2010 International Concrete Sustainability Conference, Dubai, UAE 1

Decreasing the Clinker Component in C ti M t i l P f fCementing Materials: Performance of

Portland-Limestone Cements in Concrete in Combination with Supplementaryin Combination with Supplementary

Cementing Materials

Doug Hooton, Amir Ramezanianpour

UNIVERSITY OF TORONTODEPARTMENT OF CIVIL ENGINEERINGDEPARTMENT OF CIVIL ENGINEERING


Why Portland-Limestone Cements (PLC)?Cements (PLC)?

• Portland Cement manufacturing gproduces CO2– Limestone decomposition– Fuel consumption

• Governments are preparing cap p p g pand trade limits on point source CO2 emissions

• Not new since PLC (CEM IIA-L)Not new since PLC (CEM IIA L) has been in use in Europe for > 20 years and is now the most widely used cement type


PLC in Canadian Standards

• In 2008, a new class of Portland-Limestone cements was added to the cement standard CSA A3001 with up toadded to the cement standard, CSA A3001, with up to 15% blended or interground limestone replacing cement clinker.

• The CO2 emissions from PLC are ~10% less relative to CSA Type GU (~ASTM Type I) Portland cement.

• In addition, fewer raw materials and less energy are used to produce PLCused to produce PLC.

• When properly optimized, the limestone is not inert and contributes to the properties of the cement.p p

• PLC have to meet the same set time and strength development performance as portland cement of the same type (eg. GU ---same as ASTM Type I)


Portland-Limestone Cementsin Canadian Standardsin Canadian Standards

• Changes to the CSAChanges to the CSA A3000 CementitiousMaterials standard in 2008 and to the A23.1 Concrete standard in 2009 allow use of PLC

• The National BuildingThe National Building Code of Canada was updated in 2010 to include these changesg


More Sustainable Cementing MaterialsCementing Materials

SCMs (and blended cements)

Portlandcement

Blended hydraulic

Portland-limestone

type cement type

cement type

GU GUb GUL

PLC

(GULb)


CSA A23.1 Types of Hydraulic CementsPortland Blended hydraulic Portland limestone NamePortlandcement

Blended hydrauliccement

Portland-limestonecement ***

Name

GU GUb GUL General use cement

MS MSb - Moderate sulphate-resistant cement

MH MHb MHL Moderate heat of hydration cement

HE HEb HEL High early-strength cementstrength cement

LH LHb LHL Low heat of hydration cement

HS HSb - High sulphate-HS HSbresistant cement

*** Portland-limestone cements shall not be used in sulphate exposures as defined in Table 3 of CAN/CSA-A23.1 (even when mixed with SCMs)


PLC in Sulfate Exposuresp

• Currently PLC is not allowed in sulfate exposures b th CSA A23 1 t t d d d tby the CSA A23.1 concrete standard due to concern with potential for thaumasite sulfate attack (TSA) at cool temperatures (5-10 oC).

• However, in 2010, the CSA A3001 cement standard was revised to allow PLC blended cements in sulfate exposurescements in sulfate exposures

• Research is ongoing to develop sufficient data to revise the A23.1 concrete standard to allow PLC + SCM (or blended cements) in sulfate exposures.


ThaumasiteThaumasite Form Form of of SulfateSulfate AttackAttack

30-year-old bridge column exposed to wet oxidized sulfide clay into wet oxidized sulfide clay in England

Thaumasite is not so common, but when it occurs it attacks the wholewhen it occurs, it attacks the whole matrix.

Photos from UK Expert Panel


New Test for Evaluating Mitigation f Th it S lf t Att kof Thaumasite Sulfate Attack

• A new test method, based on ASTM C1012, but with mortar bars stored in sulfate solution at 5 oCwith mortar bars stored in sulfate solution at 5 C, was standardized by CSA in 2010

• In this new test, PLCs were found to show t ti l t f th it if d th lpotential to form thaumasite, if used as the sole

binder.

• But when sufficient levels of slag fly ashBut when sufficient levels of slag, fly ash, metakaolin, and silica fume (ternary) binders were used, no thaumasite formed.

Thi th b i f CSA A3001 b i i d• This was the basis for CSA A3001 being revised in 2010, allowing blended cements with limestone


ASTM and PLC

• At least 2 producers in the USA are making p g10% limestone cements under ASTM C1157 and have used them in both structures and pavements.

• ASTM C595 may be amended in 2011 to allow for PLC blended cements.

• In support of ASTM activities, Thomas & H t d t PCA R&D SN3142Hooton prepared a report: PCA R&D SN3142, The Durability of Concrete Produced with Portland-Limestone Cement: Canadian StudiesStudies.


A3001 PLC Performance RequirementsRequirements

• In CSA A3000, the setting times and strength , g gdevelopment limits are the same for PLC as for portland cements.

• Heat of hydration limits are also the same for yMH and LH cements.

• In concrete, PLC also performs well with slag or fly ash at normal replacement levels.

• Mechanisms: Carbo-aluminate hydrates form and also fine carbonates provide nucleation sites that accelerate hydration


Cement types sold in Europe 1999 - 2004(according to Cembureau data)

5 64.03.26.1

5.55.03.41.7

6.5

51.52.1

4 8

9.5

1.91.8

5.15.42.92.1

5.6

5.71.82.2

90

100 Others

CEM V - Composite Cement

CEM IV - Pozzolanic

( g )

16.8

5.6

16.8 14.5

24 0

9.6

4.8

14.3 12.5

70

80

pe (%

)

CEM III - Blast furnace slag

CEM II - Portland-composite

CEM II - Portland-limestone

CEM II - Portland-fly ash

CEM II - Portland-pozzolana

4 83.75.4

15.0

5 42.96.2

18.9

2.15.7

24.6

2.77.0

24.0

1.26.9

24.5

7 4

31.4

40

50

60

nt T

ypes

in E

urop CEM II - Portland-slag

CEM I - Portland

PLC had the

35.4

4.8

34.2

5.4

33.7

4.2

32.1

6.8

31.6

5.91.2

27 5

4.51.47.4

20

30Cem

en largest use in 2004

Most portland-27.5

0

10

1999 2000 2001 2002 2003 2004

pcomposite cements contain

limestone too


Why PLC works: (Herfort, 2008) Limestone and cement aluminates form

Carboaluminates, which fill in porosity and increase strength + if get more

aluminates from SCM optimum will shift to higher % limestone

10

15nd

]

compressive strength measured

aluminates from SCM, optimum will shift to higher % limestone

0

5

10

of p

oros

ity a

stre

ngth

[%]

increase

10

-5

0

ive

chan

ge o

com

pres

sive

decrease

-15

-10

0 2 4 6 8 10 12 14 16 18 20 22

rela

ti c

total porosity calculated

amount of CaCO3 added [wt.-%]

Equal strength at 0 and 13% PLC


PLC + Slag, Fly Ash, or Metakaolin

10

15

nd

compressive strength measured

5

10

f po

rosi

ty a

nst

reng

th [%

]

increase

-5

0

ve c

hang

e of

ompr

essi

ve s

decrease

-15

-10

0 2 4 6 8 10 12 14 16 18 20 22

rela

tiv co

total porosity calculated

amount of CaCO3 added [wt.-%]

Research is currently underway at U of Toronto to confirm


Limestone Fineness100%

D50 (Limestone): 7 to 10 μm

50%

D50 (clinker): 15 μm

1μm 10μm 100μm0

Limestone fineness in the interground product is significantly finer thanthe clinker fraction

L. Barcelo, Lafarge


Lab Concrete Data

• Before balloted by CSA A23 1 all of• Before balloted by CSA A23.1, all of the Cement companies and several universities performed extensive ptesting for fresh, hardened, and durability properties on PLC and t th ith SCM ll dtogether with SCMs normally used.

• A couple of examples follow.


Initial concrete test results – straight cement (and limestone)[MPa]

40

10

20

30

01d 3d 7d 28d 56d

GU PLC 10 PLC 15

20

40

60

w/c 0.70 01d 3d 7d 28d 56d 91d

GU PLC 10 PLC 15

40

60

0

20

40

1d 3d 7d 28d 56d 91d

w/c 0.40GU

PLC10

w/c 0.37

GU PLC 10 PLC 15PLC15


Initial concrete test results – with 30% Slag[MPa]

40

10

20

30

40

0

10

1d 3d 7d 28d 56d

GU PLC 10 PLC 1540

60

w/cm 0.700

20

1d 3d 7d 28d 56d 91d

GU PLC10 PLC1540

60

w/cm 0.40GU PLC 10 PLC 15

0

20

40

1d 3d 7d 28d 56d 91d

GU

PLC10

w/cm 0.37GU PLC 10 PLC 15PLC15


56-day ASTM C1202 Results (w/cm = 0 40)(w/cm = 0.40)

56 Day RCPT Results56 Day RCPT Results

3000

3500

2000

2500

lom

bs

GU

PLC10CSA C-1 Exposure Limit

1000

1500Cou

l PLC10

PLC15

p

0

500

Cement-100% Cement-70%+Slag-30%


85-day ASTM C1202 Resultsy

85 Day RCPT Results

2500

3000

GU

1500

2000

ulom

bs

GU

PLC10

500

1000

Co

PLC15

0

500

Cement-100% Cement-70%+Slag-30%


Lafarge PLC Trials from 2008(Concrete International (

Jan.2010)• 8 concrete slabs were cast8 concrete slabs were cast

in Oct 2008 at Lafarge, Gatineau QC

• 80-100mm (3-4 in ) slump80 100mm (3 4 in.) slump, air-entrained, 30MPa, C-2 exposure(355kg/m3, 592 pcy)pcy)

• GU and PLC with 0, 25, 40 & 50% mixed SCM (2 slag: 1 fly ash)1 fly ash)


RCP Coulomb Values for Site Cast Cylinders & Coresy

Equal performance of GU and PLC mixes at same age and SCM content


3, 7, 28, 35-day Cylinder & 35-day Core Strengthsg

(12% limestone PLC mixes in Green)

0 25 40 50

% SCMs


Air Void, Freeze/Thaw and Chloride Diffusion DataChloride Diffusion Data


Nov. 2009 Barrier Wall

• Dufferin Construction Barrier Wall Test• Dufferin Construction Barrier Wall Test sections 23m3 of PLC+Slag vs GU+Slagg

• Queen Elizabeth Expressway in Burlington

• First MTO trial of PLC• Testing performed by Dufferin Concrete

(Holcim) and University of Toronto.


PLC Barrier Walls on QEWNov 4 2009Nov. 4, 2009

GU Cement + GUL Cement 25% Slag + 25% Slag

23 m3 of each mix was placed, 30 MPa, 60-100 mm (2.5-4 in.) slump


Nov. 2009 QEW Barrier WallQEW Barrier Wall PC +25% SLAG PLC + 25% SLAG

Shrinkage (28d) 0.038% 0.038%Strength (MPa)

1 9 5 10 31 9.5 10.33 19.3 19.47 25.6 26.828 36.9 37.95691

38.940.7

38.040.29 0 0

Freeze/Thaw Durability 94% 94%MTO LS-412 Scaling 0.24 kg/m2 0.24 kg/m2

RCP (Coulombs) 28 days 2070 149056 days 1930 1340


PLC Paving Trial Sept 27, 2010Cooperation between MTO, Dufferin Construction,

H l i d U i it f T tHolcim and University of Toronto

• New Highway 401 East bound exit to #10New Highway 401 East bound exit to #10 from collector lanes.

• 100 m of paving was done with PLC 25% Sl bi d th iPLC+25% Slag as binder, otherwise identical to GU+25% Slag control mixture.mixture.

• Pavement was 4.25 m (13 ft) wide x 280 mm (11.5 in.) thick with pre-placed dowel b k tbaskets

• ~8 m (25 ft) was wet-cured and rest used normal curing compound


Testingg

• fresh concrete tests and strength• fresh concrete tests and strength development

• Flexural and tensile strengthsFlexural and tensile strengths• Shrinkage• Freeze/Thaw and De-icer scaling testsFreeze/Thaw and De icer scaling tests• Chloride Permeability and Bulk

Diffusionus o• Temperature monitoring


Concrete Plant


PLC (GUL) Test Section

Floating and Tyning


GUL on Left and GU on Right(after tyning but before curing ( y g g

compound)


GUL Mix on left and GU Mix on right in Paver (note segregation in GU Mix)Paver (note segregation in GU Mix)


Burlap & Plastic vs Curing CompoundCompound


PLC pavement at 2 months, prior to opening to trafficprior to opening to traffic


7 & 28-Day Data (random samples from trucks)(random samples from trucks)

GU Control PLC Slump (mm) 35 20Air (%) 5 4 4 6Air (%) 5.4 4.6

Temp. (oC) 18 19

Strength (MPa)7 day 35.0 31.928 day 50.4 48.9Split Tensile (MPa)7 day 3.3 3.028 day 4.3 4.0Flexural (MPa)7 day 5.8 5.228 day 7.4 6.8


Holcim US PLC Pavements

• Holcim makes ASTM C1157 cements• Holcim makes ASTM C1157 cements with 10% limestone for use in Colorado and Utah.

• These have been used on at least 5 State paving contracts.

• In several cases the PLC was used together with Class F fly ash

Data courtesy of Al Innis, Brooke Williams, & Tom Van Dam


Colorado 2008-2009US HW 287 Near LamarUS HW 287 Near Lamar

• 6.5 Miles PCCP with 10% Limestone cement meeting ASTM C1157 and 20% Class F fly ash (CM = 540 pcy, 322 kg/m3) w/cm = 0.34and 20% Class F fly ash (CM 540 pcy, 322 kg/m3) w/cm 0.34

• 28-day flexural strength average = 695 psi (4.8 MPa)• Contractor received quality incentive per CDOT specifications • Concrete was placed in 100 F (38C) weather without problems


Lehigh Cement Terminal 20 000 Ton Silo 201020,000 Ton Silo, 2010

• In Leeds Alabama• In Leeds, Alabama• Slip-formed silo made with PLC (10%)

and 40% slagand 40% slag• Three concentric silos all slip-formed• Mix used 10% limestone blendedMix used 10% limestone blended

cement meeting ASTM C1157 HE (clinker was Type II low-alkali).

Data from Gary Knight and Colleagues


80 foot (24 m) diameter x 240 feet (72 m) highfeet (72 m) high


Three concentric silosOuter wall 33 in (0 84 m) thick at bottomOuter wall 33 in. (0.84 m) thick at bottom

Concrete Mixture for slip Form

PCY kg/m3

C1157-HE PLC 420 250

Slag 280 167

Sand 1202 716

Stone 1856 1106

Water 275 164

w/cm 0 39 0 39w/cm 0.39 0.39

Water-reducer and HRWR used


Early-age and 7-Day StrengthsLeeds D-Silo Concrete Phase I

60% Lehigh C1157 HE & 40% Slag Cement

7000 SILO 6041

Average 7 day Strengths SILO 6041 5507 psi. (38.0MPa) STD 311 psi (23 tests)

SILO 6040 5647 i ( ) STD 384 i (13 t t )

Mix ID

5000

6000

SILO 6040SILO 6039

SILO 6040 5647 psi. (38.9 MPa) STD 384 psi (13 tests) SILO 6039 6223 psi. (42.9 MPa) STD 908 psi (10 tests)

3000

4000

PSI (

4x8)

20MPa

1000

2000

Lehigh C1157HE (10% Interground Limestone Cement)

20MPa

00 20 40 60 80 100 120 140 160 180

Time (hours)

7day

Interground Limestone Cement)


Summaryy

• Portland-Limestone cements have been used successfully in numerous pavements, in a barrier wall and in a large slip-formed silo.

• PLC works well with slag and fly ash at typical g y ypcement replacement levels.

• PLC, as defined in CSA, provides a 10% reduction in CO2 emissions from cement plants

d d th b f t i t f t band reduce the carbon footprint of concrete by an additional 10% without affecting performance.

• Use of PLC should not affect concrete properties or construction practicesor construction practices.


Portland-Limestone Cement makes “Greener” ConcreteConcrete

Decreasing the Clinker Component in CtiMtilCementing ...

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