Portland cement

A pallet with Portland cement

Blue Circle Southern Cement works near Berrima, New South

Wales, Australia.

Portland cement is the most common type of cement

in general use around the world, used as a basic ingredient of concrete, mortar, stucco, and most non-speciality

grout. It was developed from other types of hydraulic

lime in England in the mid 19th century and usually originates from limestone. It is a fine powder produced by

heating materials in a kiln to form what is called clinker,

grinding the clinker, and adding small amounts of other

materials. Several types of Portland cement are available

with the most common being called ordinary Portland cement (OPC) which is grey in color, but a white Portland

cement is also available.

Portland cement is caustic so it can cause chemical burns,

the powder can cause irritation or with severe exposure

lung cancer, and can contains some hazardous components such as crystalline silica and hexavalent chromium.

Environmental concerns are the high energy consumption required to mine, manufacture, and transport the cement and the related air pollution including the release

of greenhouse gases (e.g., carbon dioxide), dioxin, NOx,

SO2, and particulates.

The low cost and widespread availability of the limestone, shales, and other naturally occurring materials used

in Portland cement make it one of the lowest-cost materials widely used over the last century throughout the

world. Concrete produced from Portland cement is one

of the most versatile construction materials available in

the world.

1 History

Freshly laid concrete

Portland cement was developed from natural cements

made in Britain beginning in the middle of the 18th century. Its name is derived from its similarity to Portland

stone, a type of building stone quarried on the Isle of Portland in Dorset, England.[1]

The development of modern Portland cement (some1
2 2 MANUFACTURING

times called ordinary or normal Portland cement) began

in 1756 when John Smeaton experimented with combinations of different limestones and additives including

trass and pozzolanas relating to the planned construction of a lighthouse[2] now known as Smeaton’s Tower.

In the late 18th century, Roman cement was developed

and patented in 1796 by James Parker;

[3] Roman cement

quickly became popular, but was largely replaced by Portland cement in the 1850s.[2] In 1811 James Frost produced a cement he called British cement.[3] James Frost

is reported to have erected a manufactory for making

of an artificial cement in 1826.[4] In 1843, Aspdin’s son

William improved their cement, which was initially called

“Patent Portland cement”, although he had no patent. In

1818, French engineer Louis Vicat invented an artificial

hydraulic lime considered the “principal forerunner”[2]

of Portland cement and "...Edgar Dobbs of Southwark

patented a cement of this kind in 1811.”[2] Portland cement was used by Joseph Aspdin in his cement patent in

1824[1] because of the cements’ resemblance to Portland

stone. The name “Portland cement” is also recorded in

a directory published in 1823 being associated with a

William Lockwood, Dave Stewart, and possibly others.[5]

However, Aspdins’ cement was nothing like modern Portland cement, but was a first step in the development

of modern Portland cement, called a 'proto-Portland

cement'.[2] William Aspdin had left his fathers company

and in his cement manufacturing apparently accidentally produced calcium silicates in the 1840s, a middle

step in the development of Portland cement. In 1848,

William Aspdin further improved his cement; in 1853,

he moved to Germany, where he was involved in cement

making.[5] William Aspdin made what could be called

'meso-Portland cement' (a mix of Portland cement and

hydraulic lime).[6] Isaac Charles Johnson further refined

the production of 'meso-Portland cement' (middle stage

of development) and claimed to be the real father of Portland cement.[7] John Grant of the Metropolitan Board of

Works in 1859 set out requirements for cement to be used

in the London sewer project. This became a specification for Portland cement. The next development with the

manufacture of Portland cement was the introduction of

the rotary kiln patented by German Friedrich Hoffmann

called a Hoffmann kiln for brick making in 1858 and

then Frederick Ransome in 1885 (U.K.) and 1886 (U.S.)

which allowed a stronger, more homogeneous mixture

and a continuous manufacturing process.[2] The Hoffman

“endless” kiln which gave “perfect control over combustion” was tested in 1860 and showed the process produced

a better grade of cement. This cement was made at the

Portland Cementfabrik Stern at Stettin, which was the

first to use a Hoffman kiln.[8] It is thought that the first

modern Portland cement was made there. The Association of German Cement Manufacturers issued a standard

on Portland cement in 1878.[9]

Portland cement had been imported into the United States

from Germany and England and in the 1870s and 1880s it

was being produced by Eagle Portland cement near Kalamazoo, Michigan, and in 1875, the first Portland cement

was produced by Coplay Cement Company under the direction of David O. Saylor in Coplay, Pennsylvania.

[10]

By the early 20th century American made Portland cement had displaced most of the imported Portland cement.

2 Manufacturing

ASTM C150 defines Portland cement as “hydraulic cement (cement that not only hardens by reacting with water but also forms a water-resistant product) produced by

pulverizing clinkers which consist essentially of hydraulic

calcium silicates, usually containing one or more of the

forms of calcium sulphate as an inter ground addition.”[11]

The European Standard EN 197-1 uses the following definition:

Portland cement clinker is a hydraulic material which shall consist of at least two-thirds

by mass of calcium silicates (3 CaO·SiO2

and 2 CaO·SiO2), the remainder consisting of

aluminium- and iron-containing clinker phases

and other compounds. The ratio of CaO to

SiO2 shall not be less than 2.0. The magnesium

oxide content (MgO) shall not exceed 5.0% by

mass.

(The last two requirements were already set out in the

German Standard, issued in 1909).

Clinkers make up more than 90% of the cement along

with a limited amount of calcium sulfate (which controls

the set time) and up to 5% minor constituents (fillers)

as allowed by various standards. Clinkers are nodules

(diameters, 0.2–1.0 inch [5–25 mm]) of a sintered material that is produced when a raw mixture of predetermined composition is heated to high temperature. The

key chemical reaction which defines Portland cement

from other hydraulic limes occurs at these high temperatures (>1,300 °C (2,370 °F) and is when the belite

(Ca2SiO4) combines with calcium oxide (CaO) to form

alite (Ca3SiO5).[12]

Portland cement clinker is made by heating, in a cement

kiln, a mixture of raw materials to a calcining temperature of above 600 °C (1,112 °F) and then a fusion temperature, which is about 1,450 °C (2,640 °F) for modern

cements, to sinter the materials into clinker. The materials in cement clinker are alite, belite, tri-calcium aluminate, and tetra-calcium alumino ferrite. The aluminium,

iron, and magnesium oxides are present as a flux allowing the calcium silicates to form at a lower temperature[13]

and contribute little to the strength. For special cements,

such as Low Heat (LH) and Sulfate Resistant (SR) types,

it is necessary to limit the amount of tricalcium aluminate

(3 CaO·Al2O3) formed. The major raw material for the

clinker-making is usually limestone (CaCO3) mixed with
3

a second material containing clay as source of aluminosilicate. Normally, an impure limestone which contains

clay or SiO2 is used. The CaCO3 content of these limestones can be as low as 80%. Secondary raw materials

(materials in the rawmix other than limestone) depend on

the purity of the limestone. Some of the materials used

are clay, shale, sand, iron ore, bauxite, fly ash, and slag.

When a cement kiln is fired by coal, the ash of the coal

acts as a secondary raw material.

2.1 Cement grinding

Main article: Cement mill

To achieve the desired setting qualities in the finished

A 10 MW cement mill, producing cement at 270 tonnes per hour

product, a quantity (2–8%, but typically 5%) of calcium sulfate (usually gypsum or anhydrite) is added to

the clinker and the mixture is finely ground to form the

finished cement powder. This is achieved in a cement

mill. The grinding process is controlled to obtain a powder with a broad particle size range, in which typically

15% by mass consists of particles below 5 μm diameter,

and 5% of particles above 45 μm. The measure of fineness usually used is the "specific surface area", which is

the total particle surface area of a unit mass of cement.

The rate of initial reaction (up to 24 hours) of the cement

on addition of water is directly proportional to the specific surface area. Typical values are 320–380 m2

·kg−1

for general purpose cements, and 450–650 m2·kg−1 for

“rapid hardening” cements. The cement is conveyed by

belt or powder pump to a silo for storage. Cement plants

normally have sufficient silo space for one to 20 weeks

of production, depending upon local demand cycles. The

cement is delivered to end users either in bags or as bulk

powder blown from a pressure vehicle into the customer’s

silo. In industrial countries, 80% or more of cement is

delivered in bulk.

3 Setting and hardening

Cement sets when mixed with water by way of a complex series of chemical reactions still only partly understood. The different constituents slowly crystallise

and the interlocking of their crystals gives cement its

strength. Carbon dioxide is slowly absorbed to convert

the portlandite (Ca(OH)2) into insoluble calcium carbonate. After the initial setting, immersion in warm water

will speed up setting. Gypsum is added as an inhibitor to

prevent flash setting.

4 Use

Decorative use of Portland cement panels on London’sGrosvenor

estate[14]

The most common use for Portland cement is in the production of concrete. Concrete is a composite material

consisting of aggregate (gravel and sand), cement, and

water. As a construction material, concrete can be cast

in almost any shape desired, and once hardened, can become a structural (load bearing) element. Concrete can

be used in the construction of structural elements like

panels, beams, road furniture, or may make cast-in situ

concrete for building superstructures like roads and dams.

These may be supplied with concrete mixed on site, or

may be provided with "ready-mixed" concrete made at

permanent mixing sites. Portland cement is also used

in mortars (with sand and water only) for plasters and

screeds, and in grouts (cement/water mixes squeezed into

gaps to consolidate foundations, road-beds, etc.).

When water is mixed with Portland cement, the product

sets in a few hours and hardens over a period of weeks.

These processes can vary widely depending upon the mix

used and the conditions of curing of the product, but

a typical concrete sets in about 6 hours and develops a

compressive strength of 8 MPa in 24 hours. The strength

rises to 15 MPa at 3 days, 23 MPa at 1 week, 35 MPa at 4

weeks and 41 MPa at 3 months. In principle, the strength

continues to rise slowly as long as water is available for

continued hydration, but concrete is usually allowed to

dry out after a few weeks and this causes strength growth

to stop.
4 5 TYPES

5 Types

5.1 General

Different standards are used for classification of Portland

cement. The two major standards are the ASTM C150

used primarily in the USA and European EN 197. EN

197 cement types CEM I, II, III, IV, and V do not correspond to the similarly named cement types in ASTM

C150.

5.2 ASTM C150

The five types of Portland cements exist, with variations

of the first three according to ASTM C150.[15]

Type I Portland cement is known as common or generalpurpose cement. It is generally assumed unless another

type is specified. It is commonly used for general construction especially when making precast and precastprestressed concrete that is not to be in contact with soils

or ground water. The typical compound compositions of

this type are:

55% (C3S), 19% (C2S), 10% (C3A), 7% (C4AF), 2.8%

MgO, 2.9% (SO3), 1.0% ignition loss, and 1.0% free

CaO

A limitation on the composition is that the (C3A) shall

not exceed 15%.

Type II gives off less heat during hydration. This type of

cement costs about the same as type I. Its typical compound composition is:

51% (C3S), 24% (C2S), 6% (C3A), 11% (C4AF), 2.9%

MgO, 2.5% (SO3), 0.8% ignition loss, and 1.0% free

CaO

A limitation on the composition is that the (C3A) shall

not exceed 8%, which reduces its vulnerability to sulfates.

This type is for general construction exposed to moderate sulfate attack and is meant for use when concrete is

in contact with soils and ground water, especially in the

western United States due to the high sulfur content of the

soils. Because of similar price to that of type I, type II is

much used as a general purpose cement, and the majority of Portland cement sold in North America meets this

specification.

Note: Cement meeting (among others) the specifications

for types I and II has become commonly available on the

world market.

Type III has relatively high early strength. Its typical

compound composition is: 57% (C3S), 19% (C2S), 10%

(C3A), 7% (C4AF), 3.0% MgO, 3.1% (SO3), 0.9% Ignition loss, and 1.3% free CaO. This cement is similar

to type I, but ground finer. Some manufacturers make a

separate clinker with higher C3S and/or C3A content, but

this is increasingly rare, and the general purpose clinker

is usually used, ground to a specific surface area typically 50–80% higher. The gypsum level may also be

increased a small amount. This gives the concrete using this type of cement a three-day compressive strength

equal to the seven-day compressive strength of types I and

II. Its seven-day compressive strength is almost equal to

28-day compressive strengths of types I and II. The only

downside is that the six-month strength of type III is the

same or slightly less than that of types I and II. Therefore,

the long-term strength is sacrificed a little. It is usually

used for precast concrete manufacture, where high oneday strength allows fast turnover of molds. It may also

be used in emergency construction and repairs and construction of machine bases and gate installations.

Type IV Portland cement is generally known for its low

heat of hydration. Its typical compound composition is:

28% (C3S), 49% (C2S), 4% (C3A), 12% (C4AF), 1.8%

MgO, 1.9% (SO3), 0.9% Ignition loss, and 0.8% free

CaO. The percentages of (C2S) and (C4AF) are relatively

high and (C3S) and (C3A) are relatively low. A limitation

on this type is that the maximum percentage of (C3A) is

seven, and the maximum percentage of (C3S) is thirtyfive. This causes the heat given off by the hydration reaction to develop at a slower rate. However, as a consequence the strength of the concrete develops slowly.

After one or two years the strength is higher than the

other types after full curing. This cement is used for very

large concrete structures, such as dams, which have a low

surface to volume ratio. This type of cement is generally not stocked by manufacturers but some might consider a large special order. This type of cement has not

been made for many years, because Portland-pozzolan

cements and ground granulated blast furnace slag addition offer a cheaper and more reliable alternative.

Type V is used where sulfate resistance is important.

Its typical compound composition is: 38% (C3S), 43%

(C2S), 4% (C3A), 9% (C4AF), 1.9% MgO, 1.8% (SO3),

0.9% Ignition loss, and 0.8% free CaO. This cement has a

very low (C3A) composition which accounts for its high

sulfate resistance. The maximum content of (C3A) allowed is 5% for type V Portland cement. Another limitation is that the (C4AF) + 2(C3A) composition cannot

exceed 20%. This type is used in concrete to be exposed

to alkali soil and ground water sulfates which react with

(C3A) causing disruptive expansion. It is unavailable in

many places, although its use is common in the western

United States and Canada. As with type IV, type V Portland cement has mainly been supplanted by the use of

ordinary cement with added ground granulated blast furnace slag or tertiary blended cements containing slag and

fly ash.

Types Ia, IIa, and IIIa have the same composition as

types I, II, and III. The only difference is that in Ia, IIa, and

IIIa, an air-entraining agent is ground into the mix. The

air-entrainment must meet the minimum and maximum

optional specification found in the ASTM manual. These

types are only available in the eastern United States and

Canada, only on a limited basis. They are a poor approach
5

to air-entrainment which improves resistance to freezing

under low temperatures.

Types II(MH) and II(MH)a have a similar composition

as types II and IIa, but with a mild heat.

5.3 EN 197

EN 197-1 defines five classes of common cement that

comprise Portland cement as a main constituent. These

classes differ from the ASTM classes.

Constituents that are permitted in Portland-composite

cements are artificial pozzolans (blastfurnace slag, silica fume, and fly ashes) or natural pozzolans (siliceous

or siliceous aluminous materials such as volcanic ash

glasses, calcined clays and shale).

5.4 CSA A3000-08

Canada - http://www.lafarge-na.com/Portland_Cement_

PDS_v6.pdf

GU, GUL* (a.k.a Type 10 (GU) cement) > General use

cement, suitable for all applications where the special

properties of any other type of portland cement are not

required.

MS > Moderate sulphate resistant cement for use in applications requiring moderate levels of sulphate resistance.

MH, MHL* > Moderate heat cement for use in applications requiring moderately low levels of heat generation

during the hydration process.

HE, HEL* > High early strength cement for use where

high early strengths are required.

LH, LHL* > Low heat cement for use in applications that

require significantly low levels of heat generation during

the hydration process.

HS > High sulphate resistant cement for use in applications that require high levels of sulphate resistance.

HS cement generally gains strength more slowly than the

other types.

• NOTE: The suffix “L

5.5 White Portland cement

Main article: White Portland cement

White Portland cement or white ordinary Portland cement (WOPC) is similar to ordinary, grey Portland cement in all respects except for its high degree of whiteness. Obtaining this colour requires some modification to

the method of manufacture; because of this, it is somewhat more expensive than the grey product. The main

requirement is to have low iron content which should be

less than 0.5% expressed as Fe2O3 for white cement and

less than 0.9% for off-white cement. It helps to have the

iron oxide as ferrous oxide (FeO) which is obtained via

slight reducing conditions i.e. operating with zero excess

oxygen at the kiln exit. This gives the clinker and cement

a green tinge. Other metals such as Cr, Mn, Ti, etc. in

trace content can also give color tinges, so for a project it

is best to use cement from a single source.

6 Safety issues

Bags of cement routinely have health and safety warnings printed on them because not only is cement highly

alkaline, but the setting process is also exothermic. As

a result, wet cement is strongly caustic and can easily cause severe skin burns if not promptly washed off

with water. Similarly, dry cement powder in contact

with mucous membranes can cause severe eye or respiratory irritation.[16][17][18][19] The reaction of cement dust

with moisture in the sinuses and lungs can also cause a

chemical burn as well as headaches, fatigue,[20] and lung

cancer.[21]

The production of comparatively low-alkalinity cements

(pH<11) is an area of ongoing investigation.[22]

In Scandinavia, France, and the UK, the level of

chromium(VI), which is considered to be toxic and a major skin irritant, may not exceed 2 ppm.

7 Environmental effects

Portland cement manufacture can cause environmental impacts at all stages of the process. These include

emissions of airborne pollution in the form of dust; gases;

noise and vibration when operating machinery and during blasting in quarries; consumption of large quantities

of fuel during manufacture; release of CO2 from the raw

materials during manufacture, and damage to countryside from quarrying. Equipment to reduce dust emissions

during quarrying and manufacture of cement is widely

used, and equipment to trap and separate exhaust gases

are coming into increased use. Environmental protection also includes the re-integration of quarries into the

countryside after they have been closed down by returning them to nature or re-cultivating them.

Epidemiologic Notes and Reports Sulfur

Dioxide Exposure in Portland Cement Plants,

from the Centers for Disease Control, states

“Workers at Portland cement facilities, particularly those burning fuel containing sulfur,

should be aware of the acute and chronic

effects of exposure to SO2 [sulfur dioxide],

and peak and full-shift concentrations of SO2

should be periodically measured.”
6 8 CEMENT PLANTS USED FOR WASTE DISPOSAL OR PROCESSING

—[23]

“The Arizona Department of Environmental Quality was

informed this week that the Arizona Portland Cement

Co. failed a second round of testing for emissions of hazardous air pollutants at the company’s Rillito plant near

Tucson. The latest round of testing, performed in January

2003 by the company, is designed to ensure that the facility complies with federal standards governing the emissions of dioxins and furans, which are byproducts of the

manufacturing process.”[24] Cement Reviews’ “Environmental News” web page details case after case of environmental problems with cement manufacturing.[25]

An independent research effort of AEA Technology to

identify critical issues for the cement industry today

concluded the most important environment, health and

safety performance issues facing the cement industry

are atmospheric releases (including greenhouse gas emissions, dioxin, NOx, SO2, and particulates), accidents, and

worker exposure to dust.[26]

The CO2 associated with Portland cement manufacture

comes from 3 sources:

1. CO2 derived from decarbonation of limestone,

2. CO2 from kiln fuel combustion,

3. CO2 produced by vehicles in cement plants and distribution.

Source 1 is fairly constant: minimum around 0.47 kg CO2

per kg of cement, maximum 0.54, typical value around

0.50 worldwide. Source 2 varies with plant efficiency:

efficient precalciner plant 0.24 kg CO2 per kg cement,

low-efficiency wet process as high as 0.65, typical modern practices (e.g. UK) averaging around 0.30. Source

3 is almost insignificant at 0.002–0.005. So typical total

CO2 is around 0.80 kg CO2 per kg finished cement. This

omits the CO2 associated with electric power consumption because this varies according to the local generation

type and efficiency. Typical electrical energy consumption is of the order of 90–150 kWh per tonne cement,

equivalent to 0.09–0.15 kg CO2 per kg finished cement

if the electricity is coal-generated.

Overall, with nuclear- or hydroelectric power and efficient manufacturing, CO2 generation can be reduced to

0.7 kg per kg cement, but can be twice as high. The thrust

of innovation for the future is to reduce sources 1 and 2

by modification of the chemistry of cement, by the use

of wastes, and by adopting more efficient processes. Although cement manufacturing is clearly a very large CO2

emitter, concrete (of which cement makes up about 15%)

compares quite favourably with other building systems in

this regard.

8 Cement plants used for waste disposal or processing

Used tires being fed to a pair of cement kilns

Due to the high temperatures inside cement kilns, combined with the oxidizing (oxygen-rich) atmosphere and

long residence times, cement kilns are used as a processing option for various types of waste streams: indeed, they efficiently destroy many hazardous organic

compounds. The waste streams also often contain combustible materials which allow the substitution of part of

the fossil fuel normally used in the process.

Waste materials used in cement kilns as a fuel

supplement:[27]

• Car and truck tires – steel belts are easily tolerated

in the kilns

• Paint sludge from automobile industries

• Waste solvents and lubricants

• Meat and bone meal – slaughterhouse waste due to

bovine spongiform encephalopathy contamination

concerns

• Waste plastics

• Sewage sludge

• Rice hulls

• Sugarcane waste

• Used wooden railroad ties (railway sleepers)

• Spent cell liner from the aluminium smelting industry (also called spent pot liner)

Portland cement manufacture also has the potential to

benefit from using industrial byproducts from the waste

stream.[28] These include in particular:

• Slag
7

• Fly ash (from power plants)

• Silica fume (from steel mills)

• Synthetic gypsum (from desulfurisation)

9 See also

• Calcium silicate hydrate

• Energetically modified cement

• Lime mortar

• Rosendale cement

10 References

[1] Gillberg, B. Fagerlund, G. Jönsson, Å. Tillman, A-M.

(1999). Betong och miljö [Concrete and environment] (in

Swedish). Stockholm: AB Svensk Byggtjenst. ISBN 91-

7332-906-1.

[2] Robert G. Blezard, “The History of Calcareous Cements”

in Hewlett, Peter C., ed.. Leaʼs chemistry of cement and

concrete. 4. ed. Amsterdam: Elsevier ButterworthHeinemann, 2004. 1-24. Print.

[3] Saikia, Mimi Das. Bhargab Mohan Das, Madan Mohan

Das. Elements of Civil Engineering. New Delhie: PHI

Learning Private Limited. 2010. 30. Print.

[4] Reid, Henry (1868). A practical treatise on the manufacture of Portland Cement. London: E. & F.N. Spon.

[5] Francis, A.J. (1977). The Cement Industry 1796–1914: A

History.

[6] Rayment, D. L. (1986). “The electron microprobe analysis of the C-S-H phases in a 136 year old cement

paste”. Cement and Concrete Research 16 (3): 341–344.

doi:10.1016/0008-8846(86)90109-2.

[7] Hahn, Thomas F., and Emory Leland Kemp. Cement mills

along the Potomac River. Morgantown, WV: West Virginia University Press, 1994. 16. Print.

[8] Reid, Henry (1877). The Science and Art of the Manufacture of Portland Cement with observations on some of its

constructive Applications. London: E&F.N. Spon.

[9] “125 Years of Research for Quality and Progress”. German Cement Works’ Association. Retrieved 2012-09-30.

[10] Meade, Richard Kidder. Portland cement: its composition,

raw materials, manufacture, testing and analysis. Easton,

PA: 1906. The Chemical Publishing Co. 4-14. Print.

[11] “Portland Cement”. dot.gov.

[12] Dylan Moore. “Cement Kilns: Clinker Thermochemistry”. cementkilns.co.uk.

[13] McArthur, Hugh, and Duncan Spalding. Engineering materials science: properties, uses, degradation and remediation. Chichester, U.K.: Horwood Pub., 2004. 217. Print.

[14] “Housing Prototypes: Page Street”. housingprototypes.org.

[15] The contractor’s guide to quality concrete construction. 3rd

ed. St. Louis, MO: American Society of Concrete Contractors ;, 2005. 17. Print.

[16] http://www.hse.gov.uk/pubns/cis26.pdf

[17] “Mother left with horrific burns to her knees after kneeling

in B&Q cement while doing kitchen DIY”. Daily Mail

(London). 2011-02-15.

[18] Pyatt, Jamie (2011-02-15). “Mums horror cement burns”.

The Sun (London).

[19] Bolognia, Jean L.; Joseph L. Jorizzo; Ronald P. Rapini

(2003). Dermatology, volume 1. Mosby. ISBN 0-323-

02409-2.

[20] Oleru, U. G. (1984). “Pulmonary function and symptoms

of Nigerian workers exposed to cement dust”. Environ.

Research 33: 379–385.

[21] Rafnsson, V; H. Gunnarsdottir; M. Kiilunen (1997).

“Risk of lung cancer among masons in Iceland”. Occup.

Environ. Med 54: 184–188.

[22] Coumes, Céline Cau Dit; Simone Courtois; Didier Nectoux; Stéphanie Leclercq; Xavier Bourbon (December

2006). “Formulating a low-alkalinity, high-resistance and

low-heat concrete for radioactive waste repositories”. Cement and Concrete Research (Elsevier Ltd.) 36 (12):

2152–2163. doi:10.1016/j.cemconres.2006.10.005.

[23] “Epidemiologic Notes and Reports Sulfur Dioxide Exposure in Portland Cement Plants”. cdc.gov.

[24] “ADEQ: Newsroom: Press Release Archive: January

2003”. azdeq.gov.

[25] “Environmental”. cemnet.com.

[26] “Toward a Sustainable Cement Industry: Environment,

Health & Safety Performance Improvement” (PDF).

wbcsd.ch.

[27] Chris Boyd (December 2001). “Recovery of Wastes in

Cement Kilns” (PDF). World Business Council for Sustainable Development. Archived from the original (PDF)

on 2008-06-24. Retrieved 2008-09-25.

[28] S.H. Kosmatka, W.C. Panarese (1988). Design and Control of Concrete Mixtures. Skokie, Illinois: Portland Cement Association. p. 15. ISBN 0-89312-087-1. As

a generalization, probably 50% of all industrial byproducts have potential as raw materials for the manufacture

of Portland cement.
8 11 EXTERNAL LINKS

11 External links

• World Production of Hydraulic Cement, by Country

• PCA – The Portland Cement Association

• Alpha The Guaranteed Portland Cement Company:

1917 Trade Literature from Smithsonian Institution

Libraries

• Cement Sustainability Initiative

• A cracking alternative to cement

• What is the Difference Between Cement, Portland

Cement & Concrete?

• Aerial views of the world’s largest concentration of

cement manufacturing capacity, Saraburi Province,

Thailand, at 14°37′57′′N 101°04′38′′E / 14.6325°N

101.0771°E

• Fountain, Henry (March 30, 2009). “Concrete Is

Remixed With Environment in Mind”. The New

York Times. Retrieved 2009-03-30.

• CDC - NIOSH Pocket Guide to Chemical Hazards

• ASTM C150
9

12 Text and image sources, contributors, and licenses

12.1 Text

• Portland cement Source: https://en.wikipedia.org/wiki/Portland_cement?oldid=675384412 Contributors: AxelBoldt, Bryan Derksen,

Aldie, William Avery, Heron, Hephaestos, Edward, Michael Hardy, MichaelJanich, Mac, Julesd, Nikai, BRG, Steinsky, Pacific1982,

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