CEMENT
http://www.tancem.com/images/inner/projects/gemini.jpg
Stephanie M. Murillo Maikut
http://www.math.lsu.edu/~bogdan/photo-albums/poland-poznan/square-town-houses.jpg
INTRODUCTION
Definition: “Cement is a crystalline compound of
calcium silicates and other calcium compounds
having hydraulic properties” (Macfadyen, 2006).
History
Lime and clay have been used as
cementing material on constructions
through many centuries.
Romans are commonly given the credit
for the development of hydraulic cement,
the most significant incorporation of the
Roman’s was the use of pozzolan-lime
cement by mixing volcanic ash from the
Mt. Vesuvius with lime.
Best know surviving example is the
Pantheon in Rome
In 1824 Joseph Aspdin from England
invented the Portland cement
(http://www.holcim.com/NZ/EN/id/71772/mod/gnm20/page/editorial.htm)
(http://pubs.usgs.gov/of/2005/1152/2005-1152.pdf)
http://www.artchive.com/artchive/r/roman/roman_pantheon.jpg
Types of Cement
Cements are considered hydraulic because of their ability to set and harden
under or with excess water through the hydration of the cement’s chemical
compounds or minerals
There are two types:
Those that activate with the addition of water
And pozzolanic that develop hydraulic properties when the interact
with hydrated lime Ca(OH)2
Pozzolanic: any siliceous material that develops hydraulic cementitious properties when
interacted with hydrated lime.
HYDRAULIC CEMENTS:
Hydraulic lime: Only used in specialized mortars. Made from calcination of clayrich limestones.
Natural cements: Misleadingly called Roman. It is made from argillaceous
limestones or interbedded limestone and clay or shale, with few raw materials.
Because they were found to be inferior to portland, most plants switched.
(http://pubs.usgs.gov/of/2005/1152/2005-1152.pdf)
Portland cement: Artificial cement. Made by the mixing clinker with gypsum
in a 95:5 ratio.
Portland-limestone cements: Large amounts (6% to 35%) of ground
limestone have been added as a filler to a portland cement base.
Blended cements: Mix of portland cement with one or more SCM
(supplementary cemetitious materials) like pozzolanic additives.
Pozzolan-lime cements: Original Roman cements. Only a small quantity is
manufactured in the U.S. Mix of pozzolans with lime.
Masonry cements: Portland cement where other materials have been added
primarily to impart plasticity.
Aluminous cements: Limestones and bauxite are the main raw materials.
Used for refractory applications (such as cementing furnace bricks) and certain
applications where rapid hardening is required. It is more expensive than portland.
There is only one producing facility in the U.S.
(http://pubs.usgs.gov/of/2005/1152/2005-1152.pdf)
(Macfadyen, 2006).
GEOLOGY (RAW MATERIALS)
The fundamental chemical compounds to produce cement clinker are:
Lime (CaO)
Silica (SiO2)
Alumina (Al2O3)
Iron Oxide (Fe2O3)
Raw materials used in the production of clinker cement
Fly ash: by-product of burning finely grounded coal either for industrial application or in
the production of electricity
(Macfadyen, 2006)
(Hoffman, 2006)
Clinker compounds in Type I portland cement
(Macfadyen, 2006)
www.recycleworks.org/images/flyash_concrete.gif
SOURCES OF CaCO3
Sedimentary deposits of marine origin (limestone)
Marble (metamorphosed limestone)
Chalk
Marl
Coral
Aragonite
Oyster and clam shells
Travertine
Tuff
LIMESTONES
Originate from the biological deposition of shells and skeletons of plants and animals.
Massive beds accumulated over millions of years.
In the cement industry limestone includes calcium carbonate and magnesium carbonate.
Most industrial quality limestones is of biological origin.
The ideal cement rock 77 to 78% CaCO3, 14% SiO2, 2.5% Al2O3, and 1.75% FeO3.
Limestone with lower content of CaCO3 and higher content of alkalis and magnesia
requires blending with high grade limestone
(Macfadyen, 2006)
(Kussmaul, 2003)
http://en.wikipedia.org/wiki/Image:Limestoneshale7342.jpg
SOURCES OF ARGILLACEOUS MINERALS
Argillaceous mineral resources:
Clay and shale for alumina and silica
Iron ore for iron
Other natural sources of silica are and alumina are:
Loess, silt, sandstone, volcanic ash, diaspore, diatomite, bauxite
Shales, mudstones, and sandstones are typically interbedded with the
limestone and were deposited as the inland waters and oceans covered the
land masses. Clays are typically younger surface deposits
(Macfadyen, 2006)
http://en.wikipedia.org/wiki/Image:ShaleUSGOV.jpg
MARKETING
Wide distribution of plants minimizes the
cost to customers.
In any market even though cement must
meet certain specifications there are other
factors that dominate, such as:
Delivered cost
Quality
Product consistency
Technical assistance and
Sales relationship with the user
companies
Factors that drive the consumption of
cement in the marketplace
Economic growth
Private and governmental capital
investment
Population growth
(Macfadyen, 2006)
MINING METHODS
Limestone deposits are mainly extracted by bench mining
in which holes are charged with ammonium nitrate and
fuel oil explosive and blasted
The rock is excavated with front end loaders (10 m3
capacity) and loaded into 70 to 90 tons haul trucks and
then transported to the primary crusher
Marl and chalk normally do not require blasting.
A trend is to use in pit moveable primary crushers and
belt conveyors to transport the rock to a fixed secondary
crusher, thereby reducing the number of trucks and
haulage distance
Underground mining of limestones is not typical, in the
U.S one plant obtains its limestone from underground
operation, using room and pillar mining method.
Clay and shale normally extracted using front end loaders
and loaded into haul trucks.
When they occur as overburden the clays and shales not
used are stored and often reused for reclamation in the
mined out areas of the quarry
(Macfadye, 2006)
http://www.heta4.com/imagesandgraphics/images/frontendloader
PROCESSING
(Macfadyen, 2006)
USES
Uses
Main use is in the fabrication of concrete and mortars
Modern uses
Building (floors, beams, columns, roofing, piles, bricks, mortar, panels, plaster)
Transport (roads, pathways, crossings, bridges, viaducts, tunnels, parking, etc.)
Water (pipes, drains, canals, dams, tanks, pools, etc.)
Civil (piers, docks, retaining walls, silos, warehousing, poles, pylons, fencing)
Agriculture (buildings, processing, housing, irrigation)
(http://pubs.usgs.gov/of/2005/1152/2005-1152.pdf)
(http://www.holcim.com/NZ/EN/id/71772/mod/gnm20/page/editorial.
html)
(http://en.wikipedia.org/wiki/Mortar_%28masonry%29)
http://www.wpclipart.com/working/construction/concrete_block.png
http://irandaily.ir/1383/2116/html/005991.jpg
SUBSTITUTES
It competes in the construction industry with concrete substitutes:
Alumina
Asphalt
Clay brick
Fiberglass
Glass
Steel
Stone Wood
Some materials like fly ash and ground granulated furnace slugs have
good hydraulic properties and are being used as partial substitutes for
portland cement in some concrete applications
(http://minerals.usgs.gov/minerals/pubs/commodity/cement/cemenmcs07.pdf)
PRODUCTION
Data in thousand metric tons
http://minerals.usgs.gov/minerals/pubs/commodity/cement/cemenmcs06.pdf
http://minerals.usgs.gov/minerals/pubs/commodity/cement/cemenmcs07.pdf
World production of hydraulic cement by region
(http://pubs.usgs.gov/of/2005/1152/2005-1152.pdf).
U.S production and consumption of portland cement
(http://pubs.usgs.gov/of/2005/1152/2005-1152.pdf)
RESOURCES
Although individual company reserves are subject to
exhaustion, cement raw materials (especially limestone) are
widespread and abundant, and overall shortages are unlikely
in the future
(http://minerals.usgs.gov/minerals/pubs/commodity/cement/cemenmcs07.pdf)
REFERENCES
Hoffman, G., 2006: Pozzolans and supplementary cementitious materials. Pages 11611172 in Industrial Minerals and Rocks 7th edition. Edited by J.E. Kogel, N.C., Trivedi,
J.M. Barker & S.T. Krudowski. Littleton, Colorado: SME
Macfadyen, J.D., 2006: Cement and cement raw materials. Pages 1121-1136 in
Industrial Minerals and Rocks 7th edition. Edited by J.E. Kogel, N.C., Trivedi, J.M.
Barker & S.T. Krudowski. Littleton, Colorado: SME
http://www.holcim.com/NZ/EN/id/71772/mod/gnm20/page/editorial.htm
Consulted April 2007
http://pubs.usgs.gov/of/2005/1152/2005-1152.pdf Consulted April 2007
http://www.artchive.com/artchive/r/roman/roman_pantheon.jpg
2007
Consulted
April
http://www.recycleworks.org/images/flyash_concrete.gif Consulted April 2007
http://en.wikipedia.org/wiki/Image:Limestoneshale7342.jpg Consulted April 2007
http://en.wikipedia.org/wiki/Image:ShaleUSGOV.jpg Consulted April 2007
http://www.heta4.com/imagesandgraphics/images/frontendloader.gif Consulted
April 2007
http://en.wikipedia.org/wiki/Mortar_%28masonry%29 Consulted April 2007
http://www.wpclipart.com/working/construction/concrete_block.png Consulted April
2007
http://irandaily.ir/1383/2116/html/005991.jpg Consulted April 2007
http://minerals.usgs.gov/minerals/pubs/commodity/cement/cemenmcs06.pdf
Consulted April 2007\
http://minerals.usgs.gov/minerals/pubs/commodity/cement/cemenmcs07.pdf
Consulted April 2007