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
2010 Concrete Sustainability Conference 2 © National Ready Mixed Concrete Association
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
2010 Concrete Sustainability Conference 3 © National Ready Mixed Concrete Association
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
2010 Concrete Sustainability Conference 4 © National Ready Mixed Concrete Association
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
2010 Concrete Sustainability Conference 5 © National Ready Mixed Concrete Association
PLC - Historical Timeline
ditio
ns
e G
U
M II
-B
-resi
stin
g)
n G
erm
any
limes
tone
add
ow 5
% in
Typ
e
y r 35%
in C
EM
n C
emen
ts
to 5
%
5% xcep
t sul
fate
-
one
cem
ent i
n
ndar
ds a
llow
l
tand
ards
allo
%) i
n G
erm
any
n U
.K.
n C
EM
II-A
o
all C
anad
ian
0 al
low
s up
llow
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
2010 Concrete Sustainability Conference 6 © National Ready Mixed Concrete Association
Cement types commercialized in Europe (according to Cembureau)
2010 Concrete Sustainability Conference 7 © National Ready Mixed Concrete Association
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
2010 Concrete Sustainability Conference 8 © National Ready Mixed Concrete Association
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)
2010 Concrete Sustainability Conference 9 © National Ready Mixed Concrete Association
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
2010 Concrete Sustainability Conference 10 © National Ready Mixed Concrete Association
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
2010 Concrete Sustainability Conference 11 © National Ready Mixed Concrete Association
CaSO4gypsum+ CSH + CH + FH3 + pore solutionpore solution
ettringite
thaumasite
Reducedmonosulfate
Ms-ss
Reduced porosity
Increased porosity
C4AH13
calcite
MonocarbonateHemicarbonateC3A CaCO3
calcite
Hertford, 2008
2010 Concrete Sustainability Conference 12 © National Ready Mixed Concrete Association
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)
2010 Concrete Sustainability Conference 13 © National Ready Mixed Concrete Association
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
2010 Concrete Sustainability Conference 14 © National Ready Mixed Concrete Association
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
2010 Concrete Sustainability Conference 15 © National Ready Mixed Concrete Association
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)
2010 Concrete Sustainability Conference 16 © National Ready Mixed Concrete Association
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)
2010 Concrete Sustainability Conference 17 © National Ready Mixed Concrete Association
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)
2010 Concrete Sustainability Conference 18 © National Ready Mixed Concrete Association
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
2010 Concrete Sustainability Conference 19 © National Ready Mixed Concrete Association
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)
2010 Concrete Sustainability Conference 20 © National Ready Mixed Concrete Association
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
Supplementary Cement Materials
2010 Concrete Sustainability Conference 21 © National Ready Mixed Concrete Association
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
Supplementary Cement Materials
No SCM 35% Slag 20% Fly AshSupplementary Cement Materials
2010 Concrete Sustainability Conference 22 © National Ready Mixed Concrete Association
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)
2010 Concrete Sustainability Conference 23 © National Ready Mixed Concrete Association
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
2010 Concrete Sustainability Conference 24 © National Ready Mixed Concrete Association
Field TrialsField Trials
Brookfield Cement Plant NSExshaw Cement Plant, AB
Brookfield Cement Plant, NS
Gatineau Concrete Plant, QC
2010 Concrete Sustainability Conference 25 © National Ready Mixed Concrete Association
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
2010 Concrete Sustainability Conference 26 © National Ready Mixed Concrete Association
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 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
2010 Concrete Sustainability Conference 27 © National Ready Mixed Concrete Association
PLC Trial Pour at Gatineau ReadyPLC Trial Pour at Gatineau Ready--Mixed Concrete Plant Mixed Concrete Plant –– October 6, 2008 October 6, 2008
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
2010 Concrete Sustainability Conference 28 © National Ready Mixed Concrete Association
PLC Trial Pour at Gatineau ReadyPLC Trial Pour at Gatineau Ready--Mixed Concrete Plant Mixed Concrete Plant –– October 6, 2008 October 6, 2008
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
2010 Concrete Sustainability Conference 29 © National Ready Mixed Concrete Association
PLC Trial Pour at Gatineau ReadyPLC Trial Pour at Gatineau Ready--Mixed Concrete Plant Mixed Concrete Plant –– October 6, 2008 October 6, 2008
Vibrating Screed Bullfloat
Broom Finish Insulated Tarps (except slab 5)
2010 Concrete Sustainability Conference 30 © National Ready Mixed Concrete Association
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
0% SCM 25% SCM 40% SCM 50% SCM
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
0% SCM 25% SCM 40% SCM 50% SCM
2010 Concrete Sustainability Conference 31 © National Ready Mixed Concrete Association
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
2010 Concrete Sustainability Conference 32 © National Ready Mixed Concrete Association
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 (%)
2010 Concrete Sustainability Conference 33 © National Ready Mixed Concrete Association
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
2010 Concrete Sustainability Conference 34 © National Ready Mixed Concrete Association
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)
2010 Concrete Sustainability Conference 35 © National Ready Mixed Concrete Association
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
2010 Concrete Sustainability Conference 36 © National Ready Mixed Concrete Association
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
2010 Concrete Sustainability Conference 37 © National Ready Mixed Concrete Association
April 2, 2009
2010 Concrete Sustainability Conference 38 © National Ready Mixed Concrete Association
PLC + 25% SCMApril 2, 2009
PLC + 50% SCM
PC + 25% SCM
PC + 50% SCM
2010 Concrete Sustainability Conference 39 © National Ready Mixed Concrete Association
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
2010 Concrete Sustainability Conference 40 © National Ready Mixed Concrete Association
Exshaw Cement Plant, Alberta• Sept 2009p
• Paving, Curbs & pumped concrete
• PC & PLC cements
• 15, 25 & 30% fly ash, y
2010 Concrete Sustainability Conference 41 © National Ready Mixed Concrete Association
Brookfield Cement Plant,Nova Scotia
O t 2009• Oct 2009
• Paving
• Blended PC & PLC cements containing 15% slag% g
• 15 & 20% fly ash
2010 Concrete Sustainability Conference 42 © National Ready Mixed Concrete Association
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
2010 Concrete Sustainability Conference 43 © National Ready Mixed Concrete Association
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)
2010 Concrete Sustainability Conference 44 © National Ready Mixed Concrete Association
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)
2010 Concrete Sustainability Conference 45 © National Ready Mixed Concrete Association
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)
2010 Concrete Sustainability Conference 46 © National Ready Mixed Concrete Association
Questions?Questions?Questions?Questions?