Slide 1

Report
Portland-limestone Cement
Presented by Derek Townson
June 16 - BCRMCA Board of Directors'
Meeting and Town Hall Meeting in
Nanaimo, BC
Portland-limestone Cement (PLC)
• Background on PLC
• Adoption Process in Canada
• PLC Concrete performance & durability tests
2
PLC IS NOT NEW
• Used successfully in Europe for over 25
years in a variety of applications and
exposure conditions
• New Only To Canada
3
Gotthard tunnel, Switzerland
• Longest train tunnel worldwide with 57 km length
• Fastest way to pass through the alps
• Cement used:
– CEM III: concrete in contact with high sulfated water
– CEM II/A-D 52,5: shotcrete and precast
– CEM II-A- L: concrete for paving
ASR and PLC
Use of CEM II A-L 42.5 R in precast industry - Italy
17/07/2015
HGRS_Title
Use of CEM II A-L 42.5 R in precast industry - Germany
17/07/2015
HGRS_Title
Historical use of limestone cements
• 1965 Heidelberger produces 20% limestone cement in Germany for
specialty applications (Schmidt 1992)
• 1979 French Cement Standards allows limestone additions.
• 1983 CSA A5 allows 5% in Type 10 (now GU) cement
• 1990, 15+/-5% limestone blended cements being used in Germany
• 1992, in UK, BS 7583 allows up to 20% in Limestone Cement
• 2000 EN 197-1 allows 5% MAC (Typ. Limestone) in all 27 common
cements, as was commonly practiced in various European cement
standards prior to that.
• 2000 EN 197-1 creates CEM II/A-L (6-20%) and CEM II/B-L (21-35%)
• 2006 CSA A3001 allows 5% in other Types than GU
• 2004 ASTM C 150 allows 5% in Types I-V
• 2007 AASHTO M85 allows 5% in Types I-V
Cement types sold in Europe
(according to Cembureau)
100
90
6.1
3.2
4.0
1.7
3.4
5.0
2.1
1.5
5
5.5
6.5
9.5
4.8
5.6
80
1.8
1.9
16.8
14.5
9.6
2.1
2.9
5.4
2.2
1.8
5.7
Others
5.1
5.6
CEM IV - Pozzolanic
CEM III - Blast furnace slag
14.3
12.5
Cement Types in Europe (%)
CEM II - Portland-composite
CEM II - Portland-limestone
16.8
70
60
CEM V - Composite Cement
CEM II - Portland-fly ash
15.0
18.9
24.6
24.0
CEM II - Portland-pozzolana
24.5
31.4
CEM II - Portland-slag
CEM I - Portland
50
40
5.4
3.7
4.8
6.2
2.9
5.4
5.7
2.1
4.2
35.4
34.2
33.7
7.0
6.8
6.9
1.2
5.9
32.1
31.6
2.7
30
20
7.4
1.4
4.5
27.5
10
0
1999
2000
2001
2002
2003
2004
PLC had the
largest use in
2004
Most portlandcomposite cements
contain limestone
too!
CSA A3000-08
Portland-limestone cement — a product obtained by
(a) blending portland cement and limestone or
(b) intergrinding portland cement clinker and limestone, to which the various
forms of calcium sulphate, water, and processing additions may be added at
the option of the manufacturer.
Notes:
(1) Limestone is designated with the suffix L. Its proportion is indicated in Clause 4.3.1.
(2) Portland-limestone cement may be produced by intergrinding or blending, or a combination
of both. The attainment of a homogeneous blend, in the dry state, of any two or more fine
materials is important. Appropriate equipment and controls should be provided by the
manufacturer.
PLC Adoption Process in Canada
Step 1
• Initially a literature review on Portland-limestone
cement (PLC) by Doug Hooton, Mike Thomas & Michelle
Nokken was undertaken. The literature review revealed
benefits and challenges with respect to PLC.
CAC Publication SN 3053
PLC Adoption Process in Canada
Step 1
May 2007 Literature Review: General Summary
Advantages: 10% GHG Emissions Reduction.
Uncertainty: Carbonation, Sulphate exposure and Potential for
Thaumasite
Unknown – Performance of PLC with HVSCM mix designs
May 2007 Literature Review: General Comments
• Results reported in the literature reviewed appears to
be affected by the quality and particle size
distribution of the limestone used and whether the
limestone was interground, blended, or added at the
mixer.
• Since limestone is easier to grind than clinker,
production to constant Blaine fineness will result in
coarser clinker and reduced performance.
• Therefore, proper interpretation of the data needs
consideration of these effects.
PLC Adoption Process in Canada
Step 2
• Various Canadian cement companies produced
prototypes of PLC at their plants.
• Chemical and physical analyses were performed with
those products. Concrete performance and durability
tests were and continue to be carried out at universities
and CAC member companies.
PLC Adoption Process in Canada
Step 3
• The tests performed with Canadian materials confirmed
the findings from the literature review and findings from
the European market.
• The prototype GULs showed, after initial optimization,
similar concrete strength as GUs. Similar concrete
strength  similar durability
• Due to mixed results from the literature review, PLC, is
not to be used in concrete subject to sulphate
exposure.
Durability Tests carried out in Canadian
• PLC cements were produced in different grinding circuits
by five cement companies:
– Clinker contents with C3A  4.5 to 12%
– Limestone content 3% to 19%
– Mortar tests and chemical analyses performed
• Concrete made with w/cm ratios  0.35 to 0.8
– Cement content  225 kg/m3 to 420 kg/m3
Concrete Tests carried out with Canadian materials
• Concrete tests with:
– 10% to 15% PLC
– Slag (15, 25, 30%, 50%) and fly ash 25%
• Slump, slump retention and air were measured
• Durability tests were performed, e.g. RCP,
freeze/thaw, salt scaling, shrinkage, sulphate
resistance, and ASR
PLC Trial Pour at Gatineau Ready-Mixed Concrete Plant – Oct. 6, 2008
Objective:
•
Field test performance of PLC concrete
with various levels of SCM in an exterior
flatwork application.
•
Control sections with Type GU + SCM
Eight Concrete Mixes:
Cement
SCM Replacement Level (%)
0
25
40
50
Type GU
X
X
X
X
Type GUL
X
X
X
X
Cementing Materials:
•
Type GU with 3.5% limestone (PC)
•
Type GUL with 12% Limestone (PLC)
•
Blended SCM = 2/3 Slag + 1/3 Fly Ash
PLC Trial Pour at Gatineau Ready-Mixed Concrete Plant – Oct. 6, 2008
Vibrating Screed
Bullfloat
Broom Finish
Insulated Tarps (except slab 5)
Gatineau PLC Trial Pour – Cylinder Strengths
Strength (MPa)
30
24.225.2
3-Day Strength
21.720.7
20
18.919.2
PC
PLC
15.315.6
10
Strength (MPa)
40
7-Day Strength
30.230.5
29.829.6
30.331.1
0% SCM
25% SCM
40% SCM
30
20
10
0
0
0% SCM
25% SCM
40% SCM
50% SCM
60
PC
Strength (MPa)
40
28-Day Strength
37.738.2
41.3
39.8
50
43.543.5
43.042.5
50% SCM
56-Day Strength
48.648.3
PLC
45.444.7
48.7
46.5
41.340.9
Strength (MPa)
50
29.428.8
40
30
30
20
20
10
10
0
0
0% SCM
25% SCM
40% SCM
50% SCM
0% SCM
25% SCM
40% SCM
50% SCM
Close up photo taken here
April 2, 2009
PLC + 25% SCM
PLC + 50% SCM
PC + 25% SCM
PC + 50% SCM
Concrete Pavement Performance
• Concrete pavement constructed with PLC (20% limestone) at a
Heidelberg cement plant. For the first 5 years, de-icing salts were
applied to the surface of the concrete pavement.
• After 13 years the pavement surface was assessed both visually and
with laboratory tests.
• The results show that:
– The surface was still undamaged by freeze-thaw. No changes in the
concrete due to weathering or loading were observed.
– Concrete strength increased with age
– Since 1997 several bridge decks and highway paveement projects
were completed with PLC in Europe.
.
Quality limits on limestone in CSA A3000
(based on EN197)
4.4.4 Limestone addition to portland-limestone cement
The limestone in portland-limestone cement shall meet the
following requirements and shall be tested at least every 6
months:
(a) The calcium carbonate (CaCO3) content calculated from
the calcium oxide (CaO) content shall be at least 75% by
mass.
(b) The methylene blue value, an indication of clay content,
determined by CSA A3004-D1, shall not exceed 1.2
g/100 g.
(c) The total organic carbon (TOC) content, when tested in
accordance with CSA A3004-D2, shall not exceed 0.5%
by mass.
These limits are only for limestone contents >5%
CSA A3001-08
No Sulphate Resistant PLC
No Blended PLC
CSA A23.1-09 Includes Concrete Made With
Portland-limestone Cements (PLC)
(3) PLC shall not be used in a sulphate exposure environment
PLC Limitations of Use
• Concretes made with PLC CANNOT BE USED IN SULPHATE
EXPOSURE (even when combined with SCMs).
• This is due to concerns about mixed information in the
literature, and to minimize any concern for Thaumasite
sulphate attack.
This issue is currently being addressed in three
independent research programs. Early results are
very encouraging.
PLC Production Issues
• As for all cements the performance of the product is strongly
influenced by cement design and fineness (Blaine and sieve
residue)
• Since limestone is typically easier to grind than clinker,
production to constant Blaine fineness will result in coarser
clinker and reduced performance. Therefore, in PLC, Blaines
need to be higher
• Since strength requirements are to be the same as for Portland
cement, each cement plant has to “optimize” the grinding of PLC
• Testing has shown that equivalent strength produces equivalent
durability performance in concrete made with Portland-limestone
cement.
Adoption Of PLC In Canada
• 2010 NBCC will reference PLC through
reference to CSA A3000-09 and CSA A23.109
• Provincial jurisdictions will legislate its use
when updating their Provincial Building
Codes or when adopting the 2010 NBCC
SUMMARY
• PLC is not NEW.
• 10% GHG savings with PLC
• In Canada all cement manufacturers will be optimizing PLC for
equivalent strength with existing PC.
• Equivalent Concrete Strength = Equivalent durability
• Do not use PLC in sulphate environments. Testing is ongoing on this
issue. Early results look promising.
• 2010 NBCC will reference PLC. Provincial Codes will reference PLC
when updates are made, or when they adopt the 2010 NBCC

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