1st International Conference on Advanced Construction
Materials
Calcium sulfoaluminate cements: opportunities and challenges
as an advanced material for the construction industry
Waltter Lopez Gonzalez
Carlos Castillo Linton
Patricia Lopez Armendariz
Monterrey, Mexico
3-6 December, 2006
CEMEX USA
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Outline
• Global Trends
• Construction Industry Implications
• The pet coke opportunity and the sulfur challenge
• Old and new sulfur paradigms in the cement industry
• Building the new sulfur paradigm through Innovation
– Belite-calcium sulfoaluminate cements
– Alite super-sulfated cements
– Alite-calcium sulfoaluminate cements
• Implications for the construction industry
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Global Trends: Sustainability
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Global Trends: Sustainability
The challenge of sustainable development arises from these two major
converging trends.
Decline in resource availability
and ecosystems
Diminishing
margin for
action
Sustainability
Impact = Population x Consumption x
Technology
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Global Trends: Demography
World population is increasing to unprecedented levels.
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Global Trends: Massive Consumption of Materials
Massive flows of material and energy are used to meet the needs of this
expanding population.
Raw Materials Consumed in the US -More
than all previous societies combined
3,000
2,500
Millions of
Metric Short
Tons
2,000
1,500
1,000
Source: USGS
500
0
1900
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1920
1940
1960
1980
1995
5
Global Trends: Atmospheric CO2 emissions are rising
Carbon Emissions from Fossil Fuel and Cement
7000000
Central and South America
Africa
6000000
Far East
Centrally Planned Asia
Middle East
Million Metric Tons of Carbon
5000000
Centrally Planned Europe
Oceania
Western Europe
4000000
Germany
North America
3000000
2000000
1000000
0
1900
1910
1920
1930
1940
1950
1960
1970
1980
1990
Source: CDIAC
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Global Trends: Global warming
Surface temperatures have warmed over the past century.
WORLD
RESOURCES
INSTITUTE
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Global Trends: Inequity
At the same time, millions of people worldwide are struggling to meet their
basic needs.
Distribution of Total World Income
• 1.3 billion people live in absolute
poverty, with incomes less than
$1/day (World Bank)
Richest
Fifth
82.7%
• 841 million people in developing
countries suffer from basic proteinenergy malnutrition (UN Food and Agriculture
11.7%
Organization)
• Nearly 1 billion people either
cannot work or are employed in
jobs where they cannot support
their family (International Labor Organization)
2.3%
1.9%
Poorest
Fifth
1.4%
(UNDP, Human Development Report 1992)
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Cement Industry Implications: Opportunities
These trends can create strategic business opportunities.
Society
Community
Environmental development
stewardship
Supply Chain
Rock
Quarry
Clinker
Kiln
Energy
Alternative
fuels
Workforce
training
Cement
Mill
Gypsum
Concrete
Plant
Buildings
& Roads
Aggregates
Waste
reuse
Industrial
ecology
markets
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Emission
trading
By-product
synergy
Industry
Material
recycling
Novel
material
research
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Cement Industry Implications: Constraints
But these trends can also create business constraints.
Environmental &
Social Impacts
• Water shortages
• Increasing toxicity
• Deforestation
• Water contamination
• Landfill shortage
• Lack of employment
• Lack of housing
• Income disparity
Legal/Market
Constraints
Business
Implications
• Regulation
• Insurance/banks
• Consumer/NGO
pressure
• Cost increases
• New compliance
requirements
• Unpredictable
energy/ raw
material supply
Actual
Constraints
• Water shortages
• Waste disposal
overloaded
• Political unrest
• Economic recession
• Reduced
consumer
demand
• Volatile markets
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Innovation is a strategy to speed the changes
Each company is embedded in a web of relationships that can create
pressure for action.
Government Agencies
Suppliers
Material
Inputs
Buyers
Organization
Products
Customers
Employees
Universities/
Schools
Banks
Investors
Legitimacy
Financial
Resources
Insurance
Consultants
Companies
Source: Hoffman, Competitive Environmental Strategy
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Trade
Assoc.
Competitors
Industry
Norms
The
Courts
NGOs
The
Press
The
Community
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The pet coke opportunity and the sulfur challenge
CEMEX Mexico invested US $1.6m to burn 100% alternative fuels in
its calcination process, saving the company $2.3 million annually.
CEMEX decided to burn 100% petcoke, a by-product of the refining process with a
lower sale price than fuel oil, at kiln no. 4 in the company’s Torreon Plant
Benefits
9 Increased clinker production by 15.7% from 2,550 to 2,950 metric tons per daywithout expanding plant capacity
9 Reduction of emissions: CO2 6%; CO,
96%; NOx, 35.7%; HCl, 70%; SO2,
87.5%; Hydrocarbon (HC), 61.1%
9 Reduction
of
specific
thermal
consumption at the kiln by 11.3% -from
885 to 785 kcal/Kg clinker- representing
96,907 Gcal/year
9 Operational stability and 50% reduction
in time to reach the maximum production
9 Reduction of specific power consumption
at the kiln by 13.7% -from 46 to 39 Kwh/Kg clinker- representing 6,105,172
Mw-h/year
9 Savings of $ 2.3 million per year
9 Reduction of 15,000 metric tons of CO2
per year
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Sulfur related issues: build-ups and plugs
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The sulfur paradigms in the cement industry
Old sulfur paradigm
New sulfur paradigm
(XIX-XX centuries)
(XXI century)
9 Minimize sulfur in the process to avoid
build-ups and plugs in the kiln
9 Optimize sulfur in the process to be
flexible and to minimize variable cost of
cement
9 Strict control of sulfur in the process to
keep it at the minimum possible (raw
materials and fuels).
9 Strict control of sulfur in the process to
assure desired sulfur phases in clinker
9 Balance SO3/Na2Oeq ratio ~ 1.0
9 SO3/Na2Oeq ratio >> 1.0
9 SO3 clinker < 1.0
9 SO3 clinker >> 1.0
9 SO3 cement < 3.5%
9 SO3 cement >> 3.5%
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Belite-calcium sulfoaluminate cements
Chemical and mineralogical comparison with other cements
Calcium
Sulfoaluminate
Cement
Chemical Composition
Calcium
Aluminate
Cement
Calcium Silicate
Cement (Portland
type I)
% weight
SiO2
13.3
5.0
Al2O3
14.6
40.5
5.5
Fe2O3
1.8
16.0
2.2
CaO
52.0
38.0
63.9
MgO
SO3
2.1
0.3
2.0
14.0
0.0
3.4
Na2O
0.29
0.13
0.27
K2O
0.64
0.05
0.79
LOI
1.2
0.3
2.8
NaO eq
0.71
0.16
0.79
Insoluble residue
0.45
4.62
0.24
Free-lime
0.37
0.11
0.73
20.2
Mineralogical composition by XRD
Main phases
Secondary phases
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C4A 3S, C2S,CS
CA, C2F
C3S, C2S
C4AF, C3S
Fe3O4, C4AF
C3A, C4AF
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Belite-calcium sulfoaluminate cements
Physical properties comparison with other cements
325 mesh
Specific Gravity
Blaine
ASTM
Sta nda rd
Units
Ca lcium
Sulfoa lumina te
Ce m e nt
Ca lcium
Alum ina te
Ce me nt
Ca lcium Silica te
Ce m e nt
(Portla nd type I)
C 430
C 188
C 204
% passing
g/cm 3
cm 2/g
97.5
3.015
7516
74.4
3.217
3390
87.6
3.109
3505
ASTM
Standard
Vicat Setting Time in mortar
in mortar
C 807
Units
Calcium
Sulfoaluminate
Cement
Calcium
Aluminate
Cement
Calcium Silicate
Cement
(Portland type I)
Initial (min)
Final (h:min)
w/c
28
0:42
0.50
246
5:02
0.50
226
5:25
0.50
c/s
0.450
0.397
0.390
Calcium Sulfoaluminate Cement
Autoclave
Expansion, %
0.21
Calcium Aluminate Cement
0.09
Calcium Silicate Cement Portland
Type I
0.11
Maximum Requirement by ASTM
C-150 and ASTM C-1157
Máx. 0.80
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Belite-calcium sulfoaluminate cements
Color comparison with other cements
Calcium Sulfoaluminate
Cement
L = 69.3
a = - 0.1
b = 9.3
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Calcium Aluminate
Cement
L = 35.2
a = 1.1
b = 7.8
Calcium Silicate Cement
(Portland Type I)
L = 54.5
a = - 1.1
b = 7.7
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Belite-calcium sulfoaluminate cement
Flexural strength comparison with other cements
Flexural Strength (MPa)
12
10
8
Calcium Sulfoaluminate
Cement
6
Calcium Aluminate
Cement
Calcium Silicate Cement
(Portland type I)
4
2
0
3h
6 h 9 h 12 h 24 h 3 d
7 d 28 d 2 m
Age
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Belite-calcium sulfoaluminate cement
Compressive Strength (Mpa)
Compressive strength comparison with other cements
60
50
40
Calcium Sulfoaluminate
Cement
30
Calcium Aluminate
Cement
20
Calcium Silicate Cement
(Portland type I)
10
0
3 h 6 h 9 h 12 h 1 d 3 d 7 d 28 d 2 m 6 m
Age
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Belite-calcium sulfoaluminate cements
Drying shrinkage comparison with other cements
0.2
0.15
Max allowed by ASTM C-596 @ 50 weeks
Calcium Sulfoaluminate
Cement
Calcium Aluminate
Cement
0.1
Calcium Silicate Cement
(Portland type I)
0.05
0
Drying shrinkage @ 28
days
Drying shrinkage @ 50
weeks
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Belite-calcium sulfoaluminate cements
Durability: volumetric stability comparison with other cements @ 6 months
Expansion (%)
0.25
Calcium Sulfoaluminate
Cement
0.2
0.15
Calcium Aluminate
Cement
0.1
Max limit for ASTM C-1012
0.05
Calcium Silicate Cement
(Portland type I)
0
Sulfate
solution
(ASTM C1012)
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Artificial sea Water (ASTM
water
C-1038)
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Belite-calcium sulfoaluminate cements
Compressive strength (MPa)
Durability: Compressive strengths after 6 months immersed in different solutions
60
Lime saturated water
(ASTM C-109)
50
Sulfate solution (ASTM C1012)
40
30
Water (ASTM C-1038)
20
Artificial sea water
10
0
Calcium
Sulfoaluminate
Cement
Calcium
Aluminate
Cement
Calcium Silicate
Cement
(Portland type I)
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Belite-calcium sulfoaluminate cement
Strengths, Opportunities and Weaknesses
Strengths:
Weaknesses:
9 High very early strength development
(Excellent opportunity when time is a
constraint)
9 Concrete pouring not as friendly as with
traditional technologies due to fast
setting time
9 Excellent sulfate resistance (Opportunity
for long term Durability)
9 Scarce long term durability data
available (Technology in the market for
about 40 years)
9 Lesser dry shrinkage than calcium
silicate
cements
(Opportunity
for
shrinkage compensating concrete)
9 Lower energy consumption at the kiln
than calcium silicate cements. (About
15% lower).
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9 Need of raw materials with high alumina
content (higher alumina content than
typical clays)
9 Higher energy consumption during
grinding process than calcium silicate
cements
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Alite-supersulfated cements
Thermodynamic and Kinetic control of mineral phases CS or C4A3S
DEM REF SAX 1450 B
DEM P2 SAX 1250 Btch
DEM CCF2 B SAX 1300
DEM Y8 B SAX 1300
2000
DEM REF SAX 1450 B
DEM P2 SAX 1250 Btch
DEM CCF2 B SAX 1300
DEM Y8 B SAX 1300
2000
1000
0
20
25
30
35
1000
0
1000
10
20
30
40
0
40
50
60
70
Position [°2Theta]
Peak List
30-0226; Brownmillerite, syn; Ca2 ( Al , Fe +3 )2 O5
33-0251; Ca3 Al2 O6
33-0256; Yeelimite, syn; Ca4 Al6 O12 S O4
37-1496; Anhydrite, syn; Ca S O4
37-1497; Lime, syn; Ca O
45-0157; Ca S O4
38-1429; Ca3 Al2 O6
33-0311; Gypsum, syn; Ca S O4 !2 H2 O
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Alite-supersulfated cements
Reduction of specific thermal consumption at the kiln (Kcal/Kg clinker)
900
K2
Before
K1
850
After
800
750
700
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5
3
1
30
28
26
24
22
18
20
16
14
12
8
10
6
4
2
29
31
27
25
23
19
21
17
15
13
11
650
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Alite-supersulfated cement
Strengths, Opportunities and Weaknesses
Strengths:
Weaknesses:
9 Higher strength development at 28 days
and longer ages than typical calcium
silicate cements
9 Strict control of raw mix composition
9 Setting times 20-60 minutes longer than
typical calcium silicate cements.
9 Lower energy consumption at the kiln
than typical calcium silicate cements.
9 Skilled kiln operators trained in the new
sulfur paradigm
9 Scarce long term durability data
available (Technology in the market for
about 20 years)
9 Flexibility in the use of raw materials and
fuels with high sulfur
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Alite-calcium sulfoaluminate cement
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Alite-calcium sulfoaluminate cement
Strengths, Opportunities and Weaknesses
Weaknesses:
Strengths:
9 Higher strength development
calcium silicate cements
than
9 Fast setting time
9 Strict control of raw mix composition
9 Excellent sulfate resistance (Opportunity
for long term Durability)
9 Lower energy consumption at the kiln
than typical calcium silicate cements.
9 Flexibility in the use of raw materials and
fuels with high sulfur
9 Skilled kiln operators trained in the new
sulfur paradigm
9 Scarce long term durability data
available (Technology not available in
the market yet)
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New cements development and implications
to the construction industry
• New product first, new technology later
Opportunity to develop a friendly concrete technology
Developing of standards to support transference to the market place
Assure consistency of products in the market
Training students and workers in the appropriate use of the new technologies
Long term evaluation of structures built with these technologies
Opportunity to capture new business opportunities in niche markets
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Thank You !!!!
Questions?
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