Cement Definition and its types by NPTEL website

CEMENT SHORT VERSION

1. Radhakrishna G. Pillai
Building Technology & Construction Management Division
Department of Civil Engineering
Indian Institute of Technology Madras, Chennai, India
Cement
(CE 3420 – Concrete Technology)

2. Outline
•Cement manufacturing
•Cement chemistry
•Cement hydration

3. •Portland cement was first patented in 1824
•Named after the natural limestone quarried on the
Isle of Portland in the English Channel
Beginning of the Industry
PCA
Isle of Portland, UK

4. Hydraulic and nonhydraulic cements
•Hydraulic cement (e.g., Portland cement)
–Hardens by reaction with water
–Hydrated products are resistant to water
–Do not require pozzolanic materials to develop the
resistance to water
•Non-hydraulic cement (e.g., Gypsum and lime
cements)
–Hardens by reaction with water
–Hydrated products are NOT resistant to water

5. Hydraulic and nonhydraulic cements
•Reaction product (i.e., gypsum cement) is unstable in waterGypsum crystals
http://edafologia.ugr.es/comun/trabajos/orla99/texto.htm; Mehta and Monteiro
(Plaster of paris)

6. Hydraulic and nonhydraulic cements
•Hydrated lime is unstable in water  Non-hydraulic
•Calcium Silicate Hydrate is stable in water 
Hydraulic

7. Hydraulic lime mortar
•Romans made “hydraulic lime mortar” by mixing
lime with a reactive volcanic ash (i.e., a pozzolanic
material) found in Pozzuoli near Naples, Italy
http://www.crisacross.com/en/2009/10/testtettest/
http://www.unifr.ch/geoscience/mineralogy/archmet/index.php?page=781

8. What is Portland cement?
•Definition by ASTM C150:
–“…A hydraulic cement produced by pulverizing clinkers
consisting essentially of hydraulic calcium silicates, and a
small amount of one or more forms of calcium sulfate as
an interground addition…”
•A general definition
–A material capable of setting, hardening and remaining
stable under water.
ASTM C150 / C150M - 09 Standard Specification for Portland Cement

9. •1871— Coplay, Pennsylvania, USA
•1889 — Hull, Quebec, Canada
Portland Cement First Produced
PCA

10. Indian cement companies
•More than 70% of the cement in India comes
from…
Company Production (MT) Installed Capacity (MT)
ACC 17,902 18,640
Gujarat Ambuja 15,094 14,860
Ultratech 13,707 17,000
Grasim 14,649 14,115
India Cements 8,434 8,810
JK Group 6,174 6,680
Jaypee Group 6,316 6,531
Century 6,636 6,300
Madras Cements 4,550 5,470
Birla Corp. 5,150 5,113
http://business.mapsofindia.com/cement/
Data may be wrong
MT = Million Tonnes

11. Primary Components and sources of Raw Materials
Necessary for Portland Cement Manufacturing

12. Sources of Raw Materials Used in Manufacture of
Portland Cement
Calcium Silica Alumina Iron Sulfate
Alkali waste
Aragonite
Calcite
Cement-kiln dust
Cement rock
Chalk
Clay
Fuller’s earth
Limestone
Marble
Marl
Seashells
Shale
Slag
Calcium silicate
Cement rock
Clay
Fly ash
Fuller’s earth
Limestone
Loess
Marl
Ore washings
Quartzite
Rice-hull ash
Sand
Sandstone
Shale
Slag
Traprock
Aluminum-ore
refuse
Bauxite
Cement rock
Clay
Copper slag
Fly ash
Fuller’s earth
Granodiorite
Limestone
Loess
Ore washings
Shale
Slag
Staurolite
Blast-furnace
flue dust
Clay
Iron ore
Mill scale
Ore washings
Pyrite cinders
Shale
Anhydrite
Calcium
sulfate
Gypsum

13. Quarry
PCA

14. Storage of raw materials
PCA

15. PCA
Measurement of chemical composition

16. Cement manufacturing - Animation
•http://www.cement.org/basics/flashtour.html

17. Cement manufacturing processes
•Wet process
–almost outdated now
•Dry process
–mostly used now-a-days

18. Dry Process Manufacture of Portland Cement – Step 1
•Stone is first reduced to 125 mm (5 in.) size, then to
20 mm (3/4 in.), and stored.
PCA

19. •Raw materials are
ground, to powder and
blended.
Dry Process Manufacture of Portland Cement – Step 2
PCA

20. Dry Process Manufacture of Portland Cement – Step 3
•Burning changes raw mix chemically into clinker.
•Four stages: Preheater, flash furnaces, and shorter
kiln.
PCA

21. Dry Process Manufacture of Portland Cement – Step 4
•Clinker with gypsum is ground into portland cement
and shipped
PCA

22. Rotary kiln (furnace)
PCA

23. What happens in the rotary kiln (furnace)?
Mindess & Young, 1981

24. Process of Clinker Production – 1
Hills 2000

25. Process of Clinker Production – 2
Hills 2000

26. Process of Clinker Production – 3
Hills 2000

27. C
3S (alite) and C
2S (belite) crystals
Alite (C
3
S) crystals in portland
clinker
[Magnification 3000X]
Light, angular  Alite (C
3
S)
Darker, rounded crystals  Belite (C
2S)
[Magnification 400X]
PCA: Kosmatka (2005)

28. Chemical formula NotationName Typical
weight %
CaO
SiO
2
H
2
O
Al
2O
3
Fe
2O
3
MgO
K
2O, Na
2O
SO
3
CO
2
C
S
H
A
F
M
K, N
S
C
Lime, calcium oxide
Silica, silicon dioxide
Water
Alumina, aluminum oxide
Iron or ferric oxide
Magnesia, magnesium oxide
Alkalis, Potassium & sodium oxides
Sulphur trioxide
Carbon dioxide
60-67
17-25
--
3-8
1-6
1-4
0.5-1.2
2-3.5
--
3CaO·SiO
2
2CaO·SiO
2
3CaO·Al
2O
3
4CaO·Al
2
O
3
·Fe
2
O
3
CaSO
4·2H
2O
C
3
S
C
2S
C
3A
C
4
AF
CSH
2
Tricalcium silicate, Alite
Dicalcium silicate, Belite
Tricalcium Aluminate
Tetracalcium Aluminoferrite
Gypsum, Calcium sulphate dihydrate
45-60
15-30
6-12
6-8
3-4
Cement Composition
M. Santhanam

29. •Clinker
–Formed by burning calcium and
siliceous raw materials in a kiln.
–Size: About 20 mm (3¼4 in.) in
diameter.
•Gypsum
–A source of sulfate, is
interground with portland
clinker to form portland cement.

–It helps control setting, drying
shrinkage properties, and
strength development.
Clinker + Gypsum = Portland Cement
PCA

30. Clinker + Gypsum = Portland Cement
•Clinker
–Limestone  CaO + CO
2 [ C + C]
–Clay  SiO
2 + Al
2O
3 + Fe
2O
3 [S + A + F]
–Clay + Limestone  3CaO.SiO
2
[C
3
S]
2CaO.SiO
2 [C
2S]
3CaO.Al
2
O
3
[C
3
A]
4.CaO. Al
2
O
3
.Fe
2
O
3

[C
4
AF]
•Gypsum  CaSO
4
.2H
2
O [CSH
2
]
•Cement  Clinker + Gypsum

31. What is hydraulic cement?
•A material capable of setting, hardening and
remaining stable under water.
•Scanning-Electron Micrograph of Cement Powder

32. Cement Production - Summary
•Limestone and clay are quarried, crushed,
stockpiled and ground separately. In the wet
process, slurries are made and blended. However,
this is uneconomical. In the dry process, the
grinding is performed with dry materials but some
water maybe added to facilitate handling.
•The ground and blended material is fed into a
rotating inclined kiln. As the material slowly moves
down the kiln, evaporation, calcination, clinkering
and cooling take place. (Clinkering is a heat
treatment where partial melting occurs.)

33. Cement Production – Summary (cont’d)
•The clinker (dark porous nodules of 6-50 mm
diameter) is further cooled with air or water. It is
ground to a powder in a ball mill, along with a small
amount of gypsum, to obtain portland cement.
(Gypsum is added to avoid the flash set of the
ground clinker.)

34. Two mechanisms of hydration
•Through-solution hydration (TSH)
–Dissolution of anhydrous compounds
–Formation of highly insoluble hydrates in solution
–Precipitation of hydrates from the supersaturated solution
•Topochemical or solid-state hydration (SSH)
–Reaction at the surface of anhydrous cement compounds
•Initially TSH and then SSH
Mehta and Monteiro

35. •Videos on cement hydration (ACBM-NSF, Univ. of Illinois, USA)
http://www.youtube.com/watch?v=VLzoD-g_o5g&feature=related

36. Hydration reactions (Oxide notation)
– reading assignment
2 (3CaO•SiO
2
)
Tricalcium silicate
+ 11 H
2
O
Water
= 3CaO•2SiO
2
•8H
2
O
Calcium silicate
hydrate (C-S-H)
+ 3 (CaO•H
2
O)
Calcium hydroxide (CH)
2 (2CaO•SiO
2)
Dicalcium silicate
+ 9 H
2O
Water
= 3CaO•2SiO
2•8H
2O
Calcium silicate
hydrate (C-S-H)
+ CaO•H
2O
Calcium hydroxide (CH)
3CaO•Al
2O
3
Tricalcium aluminate
+ 3 (CaO•SO
3•2H
2O)
Gypsum
+ 26 H
2O
Water
= 6CaO•Al
2O
3•3SO
3•32H
2O
Ettringite (AFt)
2 (3CaO•Al
2O
3)
Tricalcium aluminate
+ 6CaO•Al
2O
3•3SO
3•32H
2O
Ettringite
+ 4 H
2O
Water
= 3 (4CaO•Al
2O
3•SO
3•12H
2O)
Calcium monosulfoaluminate
3CaO•Al
2O
3
Tricalcium aluminate
+ CaO•H
2O
Calcium hydroxide
+ 12 H
2O
Water
= 4CaO•Al
2O
3•13H
2O
Tetracalcium aluminate hydrate
4CaO• Al
2
O
3
•Fe
2
O
3
Tetracalcium
aluminoferrite
+ 10 H
2
O
Water
+ 2 (CaO•H
2
O)
Calcium hydroxide
= 6CaO•Al
2
O
3
•Fe
2
O
3
•12H
2
O
Calcium aluminoferrite
hydrate
PCA: Kosmatka (2005)

37. Typical composition of cement
C
3
A (10%)
C
2S (20%)
C
4
AF
(8%)
CSH
2
(5%)

38. Relative reactivity of cement compounds (typical)
Fig. 2-29, Kosmatka (2005), PCA; Tennis and Jennings 2000
The curve
labeled “overall”
with no marker
has a
composition of
55% C
3S,
18% C
2
S,
10% C
3
A, and
8% C
4
AF
(see previous slide
for a pie-chart)

39. Peculiarity of the cement hydration process
•Simultaneous reactions between anhydrous
compounds and water
•Hydration rate varies from one reaction to the other
–Rate
aluminates > Rate
silicates
•Aluminates  Stiffening/Setting
•Silicates  Hardening/Strength development

40. •Stiffening - Loss of consistency by the plastic cement paste
–Free water  plasticity
–Loss in free water due to the adsorption by the C-S-H and AFt and evaporation
•Setting - Solidification of the plastic cement paste
–Initial set: Beginning of the solidification (unworkable)
–Final set: Complete solidification
•Hardening - Strength gain with time
–Higher C
3
S and C
3
A content  Higher early strength
–Higher proportion of C
2
S
•Slow hardening  Lower early strength and higher final strength
•Lower rate of heat of hydration
–Fineness also influences the strength development and heat evolution
Physical aspects of setting and hardening
processes

41. Hydration process (until about 14 days)
Mehta and Monteiro

42. •Ettringite (AFt) formation:
–Fast reaction, low strength and very high heat liberation
•Monosulfoaluminate (AFm) formation:
–After the depletion of sulfates and increase in aluminate
ions, AFt reacts further to become AFm
•Overall reaction:
Formation of calcium sulphoaluminates
Taylor
J/g) 1672- H( HSAC 26H HS3C A C
32
3
623 
124332
3
6 HSA3C 4H A 2C HSAC 
18432
3
63
12423
HSA3C 22H HSAC A 2C
OR
J/g) 1144- H( HSAC 10H HSC A C



43. •AFt (first): Prismatic needles
•AFm (later): Plane hexagonal crystals
–low surface area ≈ 2 m
2
/g
•Volume ≈15-20%
Mehta and Monteiro; Mindess and Young
Microstructure of calcium sulfoaluminates
Ettringite Monosulfoaluminate

Why AFt first and AFm second?

44. Formation of calcium aluminohydrate
•C
4AF may also react with gypsum, as C
3A does, but
it is much less reactive.
Young et al., 1998
 

hydroxide
aluminum-ferric
3
hydrate
aluminate umtetracalci
134
water
hydroxide
calcium
ferrite alumino
umtetracalci
4
F)H(A, F)H(A,C H14 CH2 AFC 

45.  
 
gJH /500
3CH HSC 11H S2C
3CH HSC 6H S2C

823

3
hydroxide calcium
H-S-C
323
water
silicate tricalcium
3












•Moderate reaction rate
•High strength
•High heat liberation
Formation of calcium silicate hydrate (C-S-H) and
calcium hydroxide (CH)
Young et al., 1998

46. Formation of calcium silicate hydrate (C-S-H) and
calcium hydroxide (CH)
•Slow reaction rate
•Low initial but high later strength
•Low heat liberation
•Overall reaction: C
3S + C
2S + water → C-S-H + CH
Mehta and Monteiro; Mindess et al.

 
 
gJH /250
CH HSC 9H S2C
3CH HSC 4H S2C

823

2
hydroxide calcium
H-S-C
323
water
silicate dicalcium
2













47. •C/S ratio of 1.5 to 2 ( )
•High surface area (≈ 100-700 m
2
/g)
•High covalent/ionic and Van der Waals forces
•Volume ≈ 50-65%
Taylor; Mehta and Monteiro
Microstructure of C-S-H gel
323
HSC

48. Young et al., 1998
Schematic representation of the
features of C-S-H gel

49. •Large hexagonal crystals
•Low surface area (0.5 m
2
/g)
•Low Van der Waals forces
•Volume – 20-25%
Mehta and Monteiro
Microstructure of calcium hydroxide or portlandite

50. Microstructure of hydration products
•Fibrous nature of the calcium silicate hydrates
•Broken fragments of angular calcium hydroxide crystallites
•The aggregation of fibers and the adhesion of the hydration particles
is responsible for the strength development
Dicalcium silicate hydrateTricalcium silicate hydrateHydrated normal cement
Brunauer 1962 and Copeland and Schulz 1962

51. Mehta and Monteiro
C-S-H:
Agglomerations of C-S-H
particles of 1-100 nm.
H:
Hexagonal crystals of
calcium hydroxide,
monosulfoaluminate and
calcium aluminohydrate of
about 1 μm.
C:
Capillary pores and voids of
10 nm to 1 μm.
Microstructure of hydrated cement paste

52. Morphology of hydration products in 7 days
Young et al., 1998
Cement particle
coated with C-S-H,
which is surrounded
by ettringite needles
Platelets of
monosulfoaluminate
Large crystals of
calcium hydroxide

53. Mehta and Monteiro
Dimensional range of solids and pores in hydrated
cement paste
•1 to 10
7
nanometers OR 10
-6
to 10 millimeters

54. Rate of heat evolution during hydration
Mindess & Young
Stage I: Rapid evolution of heat, lasts about 15 minutes (C
3A and some C
3S reaction).
Stage II: Dormant period, lasts until initial set occurs in 2 to 4 hours
Stage III: Rapid reaction of C
3
S during the acceleration period, with the peak being reached
at about 8-10 hours, much after final set at 4-8 hours and hardening has begun
Stage IV: Rate of reaction slows down until steady state is reached in 12-24 hours
Stage V: Steady state

55. Amount of hydration products formed
PCA, Young et al.

56. Relative volumes of pores, cement compounds, and
hydration products
PCA: Tennis and Jennings 2000
(55%)
(18%)
(10%)
(8%)
NOTE: “AFt and AFm” includes ettringite (AFt) and calcium
monosulfoaluminate (AFm) and other hydrated calcium aluminate compounds.

57. Evolution and volumes of hydration products
PCA: Kosmatka (2005)

58. Gel and pore volumes as a function of the degree of
hydration (α) and water-cement ratio (w/c)
w/c = 0.6
α 







r
e
l
a
t
i
v
e

v
o
l
u
m
e
0






































1
unhydrated cement
capillary pores
gel pores
hydration productshydration products
(gel)(gel)
w/c ≈ 0.42
α 
capillary pores
gel pores
hydration productshydration products
(gel)(gel)
unhydrated cement
w/c = 0.3
hydration productshydration products
(gel)(gel)
α 
unhydrated cement
capillary pores
gel pores
empty pores
≈ 0.5 to 10 nm  Gel pores are intrinsic part of C-S-H gel
≈10 to 10,000 nm  Capillary pores are water-filled space
between the partially hydrated cement grains

59. For degree of hydration α,
Non-evaporable water, w
ne
= 0.24α g/g of original cement
Gel water w
gel
= 0.18α g/g of original cement
Hydrated product (cement gel) volume, V
hp
= 0.68α cm
3
/g of original cement
Gel porosity = 0.26 (i.e., approximately one-fourth of C-S-H gel is pore volume)
Mindess and Young
Calculating the gel and pore volumes
For constant w/c = 0.5

60. To completely form the hydration products, the minimum w/c required = 0.42α (i.e., complete
hydration cannot occur if w/c < 0.42).
For durable concrete, it is recommended to keep it ≈ 0.35 and use chemical admixtures to
improve workability etc.
Mindess and Young
Calculating the gel and pore volumes
For degree of hydration,  = 1

61. •Determined using mercury intrusion porosimetry
•Same w/c
Evolution and distribution of pores in hydrated
cement paste with different pozzolan contents
Mehta and Monteiro

62. •Colour: Dark gray
•Specific gravity: 3.15
•Specific surface area: 300 – 500 m
2
/kg
•Grain size distributions of some cements
–Obtained by laser granulometry using a suspension of cement in ethanol
Physical Properties of Cement
de Larrardde Larrard
NOTE: Spinor E12 is a
special (micro-) cement for
grouts. La Malle cement is a
blended cement with 8% of
silica fume.
In general, 1 cm
3
of cement will occupy ≈2.1 cm
3

of space when fully hydrated  almost double
the original volume.

63. •Ordinary Portland Cement
–IS:269-1989 (classified as 33, 43 and 53 grade; the grade implies
the strength achieved by the cement mortar at 28 days)
•Portland Cement, Low Heat
–IS:12600-1989
•Rapid Hardening Portland Cement
–IS:8041-1978
•Portland-Pozzolana Cement
–IS:1489-1976
•Portland-Slag Cement
–IS 455-1976
Indian Standard (BIS) Cements

64. •Permitted constituents
–Clinker, Ground granulated blast furnace slag (GGBS), Pozzolans, Fly Ash,
Burnt shale, Limestone, Silica fume, filler, calcium sulfate and additives
•Cement types
– I: 95-100% clinker
– II/A: 80-94% clinker (further classes depending on other
constituents)
– II/B: 65-79% clinker (further classes depending on other
constituents)
– III: Blast furnace cement (5-64% clinker; III/A, III/B, III/C)
– IV: Pozzolanic cement (45-89% clinker; IV/A, IV/B)
– V: Composite cement (20-64% clinker; V/A, V/B)
•Strength classes: 32.5, 32.5 R, 42.5, 42.5 R, 52.5 & 52.5 R (R: for higher
early strength)
–For example, Portland fly ash cement CEM II/B-V 42.5 R can have 65-79% clinker, 21-
35% fly ash (V) and 0-5% filler. Also, calcium sulfate and additive may be present but
not included in 100%. It should have an early 2-day strength ≥ 20 MPa, and a standard
28-day strength ≥ 42.5 MPa & ≤ 62.5 MPa.
European Standard (CEM) Cements: According to
ENV 197-1
Ravindra Gettu

65. •Type I: General purpose
•Type II: Moderate sulphate resistance and moderate heat of hydration
–Lower C
3S and C
3A
•Type III: High early strength
–Higher C
3
S, and a higher fineness
•Type IV: Low heat of hydration
–Lower C
3
S (lower than Type II) and C
3
A
•Type V: High sulphate resistance
–Lower C
3
A
•Type IA, IIA and IIIA are Air-entrained cements
•Blended cements (ASTM C 595)
–Portland Blast-Furnace Slag Cement: Type IS (slag content of 25-70%)
–Portland-pozzolan cement: Type IP (pozzolan content of 15-40%)
American Standard (ASTM) Cements: According to
ASTM C 150

66. •High alumina or calcium aluminate cement
•Expansive cements
•Rapid setting and hardening cements
•Oil-well cements
•Sulphate-resisting cement
•White cement
Special Cements
Uses?

67. References
•Concrete, S. Mindess, J.F. Young, & D. Darwin, 2
nd
Edition, Prentice-Hall,
Englewood Cliffs, New Jersey, USA, 1981
•Concrete: Microstructure, Properties and Materials, P.K. Mehta & P.J.M. Monteiro,
3
rd
Edition, Tata McGraw Hill Education Pvt. Ltd., New Delhi
•High-Performance Concrete, P.-C. Aïtcin, E&FN Spon, London, 1998
•The Science and Technology of Civil Engineering Materials, J.F. Young, S.
Mindess, R.J. Gray and A. Bentur, Prentice Hall, Upper Saddle River, New Jersey,
USA, 1998
•Cement Chemistry, H.F.W. Taylor, Thomas Telford Publ., London, 1997
•Euro-Cements, Eds. R.K. Dhir & M.R. Jones, E&FN Spon, London, 1994
•Properties of Concrete, A.M. Neville, Pearson Education, Delhi, 2004
•Concrete Mixture Proportioning, F. de Larrard, E&FN Spon, London, 1999
•Portland Cement Association, USA, web site:
http://www.cement.org/basics/concretebasics_classroom.asp
•Cement Manufacturers’ Association (India), web site:
http://www.cmaindia.org/index.html
•Cai Yuebo, Shi Quan, Ding Jian-tong, Gong Ying and Chen Bo, Indian Concrete
Journal, 2010

68. A text book with an emphasis on the durability of
concrete