Helps for engineering students

1. Er. Mahadev Singh Saud
Acme Engineering College
Civil Engineering Department
1
Cementing Materials
Chapter: Seven

2. OUTLINE
• Cementing material
• Lime
• Types of lime
• Cement
• Types of cement
• Manufacturing process of cement
• Cement clinker
• Cementing test
2

3. Chapter: Seven
Cementing Materials
Cementing Materials:
• Posses property of cohesion or adhesion with other
materials to form a strong bond
• Used to join similar and dissimilar type of materials
• Examples: clay, lime, cement
• Their mortar are used to join these materials
3

4. Lime: General introduction
• Lime is a general term for calcium-containing
inorganic materials, in which carbonates, oxides and
hydroxides predominate.
• Strictly speaking, lime is calcium oxide or calcium
hydroxide.
• It is also the name for a single mineral (native lime) of
the CaO composition, occurring very rarely.
• The word "lime" originates with its earliest use as
building mortar and has the sense of "sticking or
adhering.”
• Lime can also refer to a sticky substance (birdlime)
smeared on branches to catch small birds.
4

5. • The rocks and minerals from which these materials are
derived, typically limestone or chalk, are composed
primarily of calcium carbonate.
• They may be cut, crushed or pulverized and chemically
altered.
• "Burning" (calcination) converts them into the highly
caustic material quicklime (calcium oxide, CaO) and,
• Through subsequent addition of water, into the less caustic
(but still strongly alkaline) slaked lime or hydrated lime
(calcium hydroxide, Ca(OH)2), the process of which is
called slaking of lime.
• When the term is encountered in an agricultural context, it
probably refers to agricultural lime.
5

6. • Otherwise it most commonly means slaked lime, as the
more dangerous form is usually described more specifically
as quicklime or burnt lime.
• Used from ancient time as cementing materials
(Dharahara, Singha Durbar)
• Extracted from limestone containing CaCo3
• Calcination of calcium carbonate gives off carbon dioxide to
produce calcium oxides.
• This calcium oxide is called “quick lime”
• Lime: high workability, plasticity, durability and less
shrinkage on drying.
• Limestone can be found in limestone hills, limestone
boulders in river side and kankar below the ground. 6

7. Production
• Excavation
• Crushing Limestone
• Grinding
• Calcination → Quicklime
• Pulverize quicklime
• Mix with water under pressure → Slaked Lime
• Drying of Slaked Lime
• Pulverizing
• Marketing in bags.

8. Calcination
CaCO3 CaO + CO2 ( > 900°C)
“quick lime”
• Calcination is carried out in kilns:
- Intermittent
- Continuous
- Rotary
- Reactor

9. Intermittent Kiln
1. Load kiln
2. Calcine
4. Unload kiln
heat
crushed limestone
1
2
4
quick lime
3. Cool
3

10. Continuous Kiln
heat
crushed limestone
ash + quick lime
heat
air

11. Rotary Kiln
Finely crushed
limestone

12. 12

13. Reactor Kiln
ground limestone Hot pressurized air
Cooling compartment

14. Properties of lime:
• Resist moisture attack
• Highly workable and durable
• Provide good resistance strength to masonry
• Posses high plasticity
• Low shrinkage
Uses of lime:
• Mortar, plastering works in wall and ceiling
• As white washing and base coat for distemper
• For manufacturing of cement
• Fixing wall, floor tiles and other joinery works
• For knotting in timber etc
14

15. Lime Pops
 If quicklime is not mixed completely with water 
some CaO will be carried to construction stage.
 In its final stage it will absorb water & CO2 from air
and will expand upto 2.5-3 times.
 This will cause cracking & pop-outs in the structure.

16. Types of Lime :
• Fat lime
• Hydraulic lime
• Poor lime
Fat lime:
• Known as rich or pure or white lime
• Slakes vigorously
• Volume increased to about 2-3 times the volume of quick lime
• Setting : solely depends on the absorption of Co2
• Contains: >93%CaO and rest silica and alumina in the form o
clay.
• Hardens very slowly, high plasticity, perfectly white
• Can be use in plastering, white washing and lime mortar16

17. Classification of Quicklime
1. According to Particle Size
• Lump Lime (10-30 cm lumps)
• Pebble Lime (2-5 cm)
• Granular Lime (~0.5 cm)
• Crushed Lime (~5-8 mm)
• Ground Lime (passes #10 sieve, by grinding crushed
lime)
• Pulverized Lime (passes #100 sieve)

18. Classification of Quicklime
2. According to Chemical Composition
• High-Calcium Quicklimes (~90% CaO)
• Calcium Quicklime (75% CaO)
• Magnesian Quicklime ( > 20% of MgO)
• Dolomitic Quicklime ( > 25% of MgO)
3. According to Intended Use
• Mortar Lime
• Plaster Lime

19. Properties of Fat Lime
1. Composition:
• Produced from sea shell, coral deposits etc or from lime stone
• Containing impurities like free sand and soluble silica
combined with Al, Mg, 𝐂𝐎𝟑
−−
etc.
• If the proportion of free sand is large, the resulting lime
becomes progressively poor and is called poor or lean lime.
2. Behavior in slaking:
• Fat lime slakes rapidly when water is added giving out
considerable heat and making hissing and cracking noise and
increases 2 to 3 times its original volume.
• If it is exposed to air, it absorbs moisture and 𝐂𝐎𝟐
.
from the
atmosphere and becomes inert Ca𝐂𝐎𝟑
−−
or chalk again and
loses its cementing power.
• For developing the cementing power, quick lime must be
slaked with water as early as possible, after it is obtained from
the kiln. 19

20. 3. Shrinking:
• Fat lime has a greater tendency to shrink and crack as it
dries.
• To prevent this, a large quantity of sand (2 to 3 times) must
be mixed with it to prepare mortar.
4. Hardening or setting:
• Fat lime is hydrated calcium oxide and sets by the
absorption of CO2 from the air.
Ca (OH) 2 + CO2 ==> CaCO3 + H2O
• Crystals of CaCO3 are formed and the water goes by
evaporation.
• Fat lime hardens only where it comes in contact with air, as
in plaster work.
20

21. • In the interior of thick walls, it does not acquire strength as
CO2 i.e. air cannot reach there.
• Mixing of sand (2 to 3 times) forms pores for access of CO2
and helps hardening.
5. Strength:
• Crystals of CaCO3 formed by fat lime are not very strong.
• Therefore, does not possess much strength and is used for
plastering walls, while washing etc. in exposed positions.
21

22. Hydraulic lime
• It is a variety of lime, a slaked lime used to make lime
mortar.
• Hydraulicity is the ability of lime
• To set under water.
• Hydraulic lime is produced by heating calcining limestone
that contains clay and other impurities.
• Calcium reacts in the kiln with the clay minerals to
produce silicates that enable the lime to set without
exposure to air.
• Any unreacted calcium is slaked to calcium hydroxide.
• Hydraulic lime is used for providing a faster initial set
than ordinary lime in more extreme conditions (including
under water). 22

23. Use in construction
Hydraulic lime is a useful building material for the following
reasons:
• It has a low modulus of elasticity.
• There is no need for expansion (movement) joints.
• It allows buildings to "breathe", and does not trap moisture
in the walls.
• It has a lower firing temperature than Portland cement, and
is thus less polluting.
• Stone and brickwork bonded with lime is easier to re-use.
• It is less dense than cement, thus less cold bridging.
• Lime re-absorbs the carbon dioxide (CO2) emitted by its
calcination (firing), thus partially offsetting the large
amount emitted during its manufacture.. 23

24. Hydraulic lime:
• Set in absence of Co2 under water
• Obtained by burning kankar or clayey limstone
• May be feebly hydraulic, moderately hydraulic and
eminently hydraulic lime depending upon the clay
content.
• Presence of clay reduces the slaking and increase
hydraulic properties of lime
• Eminently hydraulic lime contains about 30% of clay
and also called as natural cement
• Slakes difficulty with no more increase in volume
• Hardens soon, can be used as mortar for heavy
construction and used in lime concrete.
• Grayish white in color 24

25. Poor Lime :
• Clay content is more than 30%
• Slakes very slowly and form a thin paste with water
• Poor binding property
• Used in inferior type of works
• Also known as lean lime
25

26. Limestone Uses
• Limestone is used as a building material, and to purify iron in blast
furnaces. It is also used in the manufacture of glass, and of cement
(one of the components of concrete)
• Glass is made by melting sand and then cooling it – flat sheets of glass
for windows are made by floating molten glass on a layer of molten
tin
• Glass manufacturers add sodium carbonate to sand during the
manufacturing process, to reduce the melting temperature of the
sand and so save energy – the sodium carbonate decomposes in the
heat to form sodium oxide and carbon dioxide, but this makes the
glass soluble in water
• Calcium carbonate (limestone) is therefore also added, to stop the
glass dissolving in water – the calcium carbonate decomposes in the
heat to form calcium oxide and carbon dioxide

27. Cement
• Important engineering materials
Used as binding materials:
• Cement mortar, RCC, Cement slurry, grouting
• Widely used in building, road, bridge, water tank,
dams, tunnel constructions etc
Advantages of cements:
• High plasticity, workability, higher moisture resistivity
• Provide good strength 27

28. Basic Ingredients of OPC
• Lime (CaO)- 60-65%
• Silica (SiO2)- 17-25%
• Alumina (Al2O3)- 3-8%
• Calcium sulphate (CaSO4)- 3-4%
• Ferrous Oxide (Fe2O3)- 0.5-6%
• Magnesium oxides (MgO)- 0.5-4%
• Sulphur Trioxides (SO3)- 1-2%
• Alkalies – small amount
• Soda and Potash (Na20, K2O)- 0.5-1%
28

29. Lime:
• Major constituents of cement
• Provides plasticity to the cement
• Make cement sound and strong (if in right proportion)
• Excess lime causes cement unsound, causes
expansion and disintegration
29

30. Silica:
• Major constituents of cement
• Helps in formation of dicalcium silicate and tricalcium
silicates
• Responsible for the strength of cement
• Excess silica increases the strength but reduces the setting
time of cement
30

31. Alumina:
• Imparts quick setting quality of cements
• Lowers the clinkering temperature of cement
• Excess amount reduces the strength of cement
Calcium sulphate:
• In the form of gypsum is added to the cement clinker
before grinding
• Increases the initial setting time of cement
31

32. Ferrous oxides:
• Increases the hardness of cement
• Provides the color to the cement
• Acts as flux and helps to fuse raw materials of cement
Magnesium oxides:
• Imparts hardness to the cement
• Imparts color to the cement
• Excess amount causes unsound to the cement
32

33. Sulphur trioxides:
• Makes cement sound if in proper amount
Alkalies:
• Should present in small quantity
• Excess alkalies causes efflorescence
• Excess amount causes alkali-aggregate reaction
33

34. Harmful ingredients of cement
• Excess alkali oxides in cement such as potassium
oxides and sodium oxides causes failure of structure
made by such cement
• Alkalies oxides causes cracks in mortar made from
such cement
• K2O and Na2O
• MgO
34

35. PRODUCTION STEPS
1) Raw materials are crushed, screemed & stockpiled.
2) Raw materials are mixed with definite proportions
to obtain “raw mix”.
3) They are mixed either dry (dry mixing) or by
water (wet mixing).
4) Prepared raw mix is fed into the rotary kiln.
5) As the materials pass through the kiln their
temperature is rised upto 1300-1600 °C. The
process of heating is named as “burning”.
6) The output is known as “clinker” which is 0.15-5
cm in diameter.

36. 5) Clinker is cooled & stored.
6) Clinker is ground with gypsum (3-6%) to
adjust setting time.
7) Packing & marketting.

39. THE CEMENT MANUFACTURING PROCESS
1. BLASTING : The raw materials that are used to manufacture cement (mainly limestone and clay) are
blasted from the quarry.
Quarry face
1. BLASTING 2. TRANSPORT
3. CRUSHING AND TRANSPORTATION : The raw materials, after crushing, are transported to
the plant by conveyor. The plant stores the materials before they are homogenized.
quarry
3. CRUSHING & TRANSPORTATION
2. TRANSPORT : The raw materials are loaded into a dumper.
crushing
conveyor
dumper
storage at
the plant
loader

40. THE CEMENT MANUFACTURING PROCESS
1. RAW GRINDING : The raw materials are very finely ground in order to produce the raw mix.
1. RAW GRINDING
Raw grinding and burning
2. BURNING
2. BURNING : The raw mix is preheated before it goes into the kiln, which is heated by a flame that can
be as hot as 2000 °C. The raw mix burns at 1500 °C producing clinker which, when it leaves the kiln, is
rapidly cooled with air fans. So, the raw mix is burnt to produce clinker : the basic material needed to
make cement.
conveyor Raw mix
kiln
cooling
preheating
clinker
storage at the
plant
Raw mill

41. REACTIONS IN THE KILN
• ~100°C→ free water evaporates.
• ~150-350C°→ loosely bound water is lost from
clay.
• ~350-650°C→decomposition of
clay→SiO2&Al2O3
• ~600°C→decomposition of MgCO3→MgO&CO2
(evaporates)
• ~900°C→decomposition of CaCO3→CaO&CO2
(evaporates)

42. • ~1250-1280°C→liquid formation & start of
compound formation.
• ~1280°C→clinkering begins.
• ~1400-1500°C→clinkering
• ~100°C→clinker leaves the kiln & falls into a
cooler.
 Sometimes the burning process of raw materials
is performed in two stages: preheating upto
900°C & rotary kiln

43. Composition of cement clinker
• During manufacturing of cement, all the ingredients
except gypsum is heated up to 14000C to 15000C
• After heating fuse mass of diameter about 0.3mm to
2.5mm is formed which is called as clinker
• Grinding of clinker with gypsum is done then is ready
for packing
43

44. 44

45. THE CEMENT MANUFACTURING PROCESS
1.GRINDING : The clinker and the gypsum are very finely ground giving a “pure cement”. Other secondary
additives and cementitious materials can also be added to make a blended cement.
1. GRINDING
Grinding, storage, packing, dispatch
2. STORAGE, PACKING, DISPATCH
2. STORAGE, PACKING, DISPATCH :The cement is stored in silos before being dispatched either in
bulk or in bags to its final destination.
clinker
storage
Gypsum and the secondary
additives are added to the clinker.
silos
dispatch
bags
Finish grinding

46. Bouge compounds
• After all the compounds undergo some chemical
combination during manufacturing process following
end products can be realized in cement which are
called Bouge compounds and these are :
• Alite – C3S- 25-50%
• Belite- C2S- 25-40%
• Celite – C3A- 5-11%
• Felite- C4AF- 8-14%
46

47. 47
Name
Chemical
Formula
Abbreviatio
ns
Tri Calcium
Silicate
3CaO.SiO2 C3S
Di Calcium Silicate 2CaO.SiO2 C2S
Tri Calcium
Aluminate
3CaO.Al2O3 C3A
Tetra Calcium
Alumino Ferrite
4CaO.Al2O3.Fe2O3 C4AF

48. Tricalcium Aluminate (C3A):
• On adding water it is earliest to hydrates
• Contributes to the strength of the cement paste at one to
three days
• In advance age it causes retrogression in the
development of strength
• Develop large amount of heat of hydration,
• It causes cracks in the paste and disintegrates the
hardened paste or concrete
• It acts as flux for the fusion of clinker and reduces the
temperature of fusion, resulting in the saving of fuel.
48

49. Tricalcium silicates (C3S):
• Hydrates immediately next to C3A
• Contributes to the early strength to the cement paste or
concrete
• It contributes most to the strength development during
the first four week
Dicalcium silicates (C2S):
• Gain in strength of C2S has been found after 28 days.
• At seven days no strength develops in C2S
• At the age of 1 year, C3S and C2S both compounds
contributes equally to the ultimate strength.
49

50. Tetra-calcium alumino-ferrite (C4AF)
• Considered as inert materials
• It acts as flux for clinker fusing at lower temperature
• Practically it doesn’t contribute in any strength
development process
• Increase the volume of cement
50

51. 51
C3S C2S C3A C4AF
Rate of Reaction Moderate Slow Fast Moderate
Heat Liberation High Low Very High Moderate
Early Cementitious Value Good Poor Good Poor
Ultimate Cementitious Value Good Good Poor Poor
ASTM Type & Name of P.C. Average Compound Composition
C3S C2S C3A C4AF
Type I - O.P.C. 49 25 12 8 General Purpose
Type II - Modified 46 29 6 12 For Moderate Heat of Hydration
Type III - High Early
Strength 56 15 12 8
C3S&C3A increased, C2S
decreased
Type IV - Low Heat P.C. 30 46 5 13 C2S increased
Type V - Sulfate Resistant
P.C. 43 36 4 12
Limit on C3A≤5%,
2C3A+C4AF≤25%

52. Types of cement
• OPC (Ordinary Portland Cement)
• High Alumina Cement
• Portland Slag cement
• Rapid Hardening Cement
• Low heat Cement
• Quick Setting Cement
• White Cement
• Colored Cement
• Portland Pozzolana Cement
52

53. Ordinary Portland cement:
• Common type of cement having medium rate of strength
development and medium rate of heat generation.
• Initial Setting time: 30 min
• Final setting time: 10 Hrs
• Higher resistance against dry shrinkage and cracking
• Less resistance to chemical attack
• Widely accepted in all types of general construction
53

54. High Alumina Cement: (for under water construction)
• A type of rapid hardening cement
• Manufactured by fusing the limestone and bauxite at high
temperature
• Contains 35% of alumina
• Posses chocolate color
• Higher resistance against sulphate attack, fire and acid.
• Initial setting time is higher than that of OPC (2.5 to 3 hrs)
• But final setting is quick due to which heat generation is
also fast
• Gains higher strength in short time
• Unsuitable for mass concrete and expensive than OPC
54

55. Portland Slag Cement:
• Obtained by mixing slag from the blast furnace with
cement clinker and gypsum and grinding them in the ball
mill.
• Has less heat of hydration
• Better resistance to acid and other corrodent environment
• Rate of strength development is slightly lower than that of
OPC
• Generally used for mass concreting works
• All other properties are similar to the OPC
55

56. Rapid hardening cement:
• Gives strength faster than that of OPC
• Initial and final setting time is similar to OPC
• Contains more C3S
• Finer than OPC
• Used in that place where formworks is to be removed
soon
• Lighter than OPC
• Curing period is also shorter than that of OPC
• Having higher early strength than OPC
56

57. Low heat cement:
• Lesser heat of hydration
• Decrease in the percentage of C3S and increase in
percentage of C2S
• Posses less amount of compressive strength
• Used in mass concrete works
Quick setting cement:
• Amount of gypsum is reduced
• Aluminum sulphate is added to get initial setting time
less than 5 minute and final setting time less
than30minutes
• Fineness also accelerates the setting time of cement
57

58. White Cement:
• Same strength as that of OPC
• Greater aesthetic values
• Clear white in color due to absence of Iron oxides and
magnesium oxides in cement
• Cement is heated in the kiln where Oil is used as fuel
instead of coal to avoid the contamination by coal ash.
• Care should be taken at grinding stage of clinker
• More expensive than OPC
• Used in finished surfacing works, tile joints, mortar for
marble, some aesthetic precast works
58

59. Colored cement:
• For aesthetical works: floor finish, windowsill, stair
treads etc
• Obtained by adding 5 t0 15% of suitable coloring
compound before grinding of cement
• Iron oxides, magnesium oxides, chromium oxides or
cobalt oxide is added to obtained red, yellow, green or
blue color in cement
• More expensive than OPC
59

60. Portland Pozzolana Cement:
• Contains about 80% clay along with lime, magnesia and
iron oxides etc
• Pozzolana itself has no cementing value but when
mixed with lime produces cementing property.
• More resistant to chemical attack and hardens slowly
• About 70% by weight of OPC clinker is mixed with
30% by weight of pozzolana and grinded first in ball
mill and then in tube mill to get the pozzolana cement
• Has lower heat of hydration and requires long period of
wet curing for better strength
• It is cheaper than OPC
60

61. Test of Cement
• Consistency test
• Setting time test of cement
• Soundness test
• Compressive strength test
Test of mortar
Adhesiveness to building Unit Test
 Tensile strength test
(Refer manual and book for more details)
61

62. Compressive strength Test
• Mortar of 1:3 is taken with 0.4 w/c ratio
• Moulds of either cube size 70.6mm or 76mm
• Cement required 185gm or 235gm
• Cubes are tested in compression testing machine at end
of 3 days and 7 days
• Testing of cubes are carried out on their three sides
without packing . Average value is then worked out.
• Load is applied uniformly at the rate of 350kg/cm2
• CS > 115kg/cm2 (3days), CS >175kg/cm2(7 days)
62

63. Tensile strength Test
• 1:3 mortar with 8% water by weight
• 12 standard briquettes are prepared
• Quantity of cement may be 600gm for 12 briquettes
• Six briquettes are tested after 3 days and 7 days . Rate
of loading 35kg/cm2
• X-sectional are of briquette at least section is 6.45cm2
• Ultimate tensile stress = failing load/6.45
• At 3 days TS>20kg/cm2, at 7 days TS>25kg/cm2
63

64. Consistency Test
• 300gm of cement is taken with 30% water
• Fill the mould of Vicat apparatus
• The interval between the addition of water to the
commencement of filling of mould is known as the
time of gauging and it should be 33/4 to 41/4 minutes
• Vicat apparatus is attached with movable rod
weighing 300gmand having diameter and length as
10m and 50mm respectively
• Square needle(1mm*1mm) for initial setting time,
plunger for consistency test, needle with annular
collar for final setting time
• Settlement of plunger is noted and if the penetration
is betn 5 to 7mm from bottom of mould, the water
added is correct
64

65. Soundness Test
• Test to detect the presence uncombined lime in
cement
• Test performed with the help of Le chatelier.
• Brass mould of 30mm dia. and 30mm height
• There is split in mould and it doesn’t exceed
0.50mm
• On either side of split there are two indicators
with pointed ends
• Thickness of mould cylinder is 0.50mm
65

66. 66

67. 67

68. 68

69. World production of hydraulic cement by region
(http://pubs.usgs.gov/of/2005/1152/2005-1152.pdf).