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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
2010 International Concrete Sustainability Conference, Dubai, UAE 2
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
2010 International Concrete Sustainability Conference, Dubai, UAE 3
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)
2010 International Concrete Sustainability Conference, Dubai, UAE 4
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
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More Sustainable Cementing MaterialsCementing Materials
SCMs (and blended cements)
Portlandcement
Blended hydraulic
Portland-limestone
type cement type
cement type
GU GUb GUL
PLC
(GULb)
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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)
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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.
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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
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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
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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.
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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
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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
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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
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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
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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
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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.
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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
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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
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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%
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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%
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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)
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RCP Coulomb Values for Site Cast Cylinders & Coresy
Equal performance of GU and PLC mixes at same age and SCM content
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3, 7, 28, 35-day Cylinder & 35-day Core Strengthsg
(12% limestone PLC mixes in Green)
0 25 40 50
% SCMs
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Air Void, Freeze/Thaw and Chloride Diffusion DataChloride Diffusion Data
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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.
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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
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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
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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
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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
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PLC (GUL) Test Section
Floating and Tyning
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GUL on Left and GU on Right(after tyning but before curing ( y g g
compound)
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GUL Mix on left and GU Mix on right in Paver (note segregation in GU Mix)Paver (note segregation in GU Mix)
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Burlap & Plastic vs Curing CompoundCompound
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PLC pavement at 2 months, prior to opening to trafficprior to opening to traffic
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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
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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
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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
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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
2010 International Concrete Sustainability Conference, Dubai, UAE 40
80 foot (24 m) diameter x 240 feet (72 m) highfeet (72 m) high
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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
2010 International Concrete Sustainability Conference, Dubai, UAE 42
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)
2010 International Concrete Sustainability Conference, Dubai, UAE 43
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.