Cement

CEMENT
DEFINITION
A cement is a binder, a substance
used for construction that sets,
hardens, and adheres to other
material to bind them together
Cement basically constituents of two different
types of compound – Argillaceous compound
(clay) & Calcareous compound (lime)

CEMENT
Cement Ingredients Formula %
Lime 𝐶𝑎𝑂 62-65
Silica 𝑆𝑖𝑂2 17-25
Alumina 𝐴𝑙2 𝑂3 3-8
Gypsum 𝐶𝑎𝑆𝑂4 3-4
Iron Oxide 𝐹𝑒2 𝑂3 3-4
Magnesia 𝑀𝑔𝑂 1-3
Sulphur 𝑆 1-2
Alkali 𝑁𝑎2 𝑂, 𝐾2 𝑂 0.2-1
Raw Materials Of Cement

CEMENT
Functions of Different Ingredients in Cement
1. LIME
 Lime Imparts strength and soundness (change in volume) to the cement
 If it is in excess it makes the cement unsound, causes it to expand and disintegrate.
 If it is in deficiency it reduces the strength of the cement and causes it to set quickly.
2. SILICA
 Silica also imparts strength to the cement.
 If it is in excess, it increases the strength of the cement but also increase the setting
time of the cement.

CEMENT
3. Alumina
 Alumina imparts quick setting properties to the cement.
 It acts as a flux and help in reducing the clinkering temperature during the burning of
the cement.
 If it is in excess it weakens the cement.
4. Gypsum
 It helps in increasing the initial setting time of the cement.
 It prevents flash set.

CEMENT
5. Iron Oxide
 It Imparts colour, strength, hardness and toughness to the cement.
 It imparts reddish brown tint in the cement.
6. Magnesia
 It also imparts colour and hardness to the cement. It gives yellow tint to the cement.
 If it is in excess it makes the cement unsound.

CEMENT
7. Sulphur
 It is also responsible for inducing the soundness in the cement.
8. Alkali
 Presence of alkalis in cement leads to the efflorescence and staining of the structure in
which the cement is used for construction.
Efflorescence – Alkali absorb moisture and reacts with it and leads to the development of white grey
spot over the surface of the structure

CEMENT
Manufacturing of Cement
1. Manufacturing of cement is carried out in 3 operations.
 Mixing of raw ingredients
 Burning
 Grinding
2. Generally two methods are available for the manufacturing of cement.
 Dry process method (Modern method)
 Wet process method

CEMENT
Bogues Compound
When water is added in the cement it reacts with the ingredients of the cement clinker
chemically and results in the formation of complex chemical compound termed as Bogues
compound
Tricalcium Silicate 𝐶3 𝑆 3𝐶𝑎𝑂. 𝑆𝑖𝑂2 Alite 30 – 50 %
Dicalcium Silicate 𝐶2 𝑆 2𝐶𝑎𝑂. 𝑆𝑖𝑂2 Belite 20 – 45 %
Tricalcium Aluminate 𝐶3 𝐴 3𝐶𝑎𝑂. 𝐴𝑙2 𝑂2 Celite 8 – 12 %
Tetra Calcium
Alumina ferrite
𝐶4 𝐴𝐹 4𝐶𝑎𝑂. 𝐴𝑙2 𝑂3 𝐹𝑒2 𝑂3 Felite 6- 10 %

CEMENT
1. Tri-Calcium Silicate
 This compound is formed with in a week on the addition of water in cement.
 It is responsible for the development of strength of the concrete in its initial age.
 If in any structure early development of strength is required proportion of tri-calcium
silicate is increased. For ex- prefabricate concrete construction, cold weather concrete,
where form work is to be removed early in speedy construction.
 Heat of hydration of tri-calcium silicate is higher in comparison to di-calcium silicate
Bogues Compound

CEMENT
Bogues Compound
2. Di-Calcium Silicate
 It is the last compound that is formed during the hydration process which may take an
year or so for its formation.
 It is responsible for progressive strength of the concrete in its later stage, it means it
gives ultimate strength to the structure.
 Heat of hydration is very less in this case.
 Di-calcium silicate in high proportion is used in cement in hydraulic structure ( gravity
dams, canals etc.), bridges, mass concreting etc.
𝐶3 𝑆 gives faster rate of reaction accompanied by greater heat
evolution and gives early strength.
On the other hand, 𝐶2 𝑆 hydrate and hardens slowly and provides
much of the ultimate strength.

CEMENT
Bogues Compound
3. Tri-Calcium Aluminate
 It is formed within 24 hours of the addition of water in the cement
 This compound is responsible for maximum evolution of heat of hydration.
 𝐶3 𝐴 is fast reacting with water and may lead to an immediate setting of paste and this
process is termed as flash set.
 𝐶3 𝐴 provides weak resistance against sulphate attack.

CEMENT
Bogues Compound
4. Tetra-Calcium Aluminate ferrite
 It is also formed with in 24 hours of the addition of the water.
 This compound is also responsible for high heat of hydration.
𝐶3 𝐴 and 𝐶3 𝐴𝐹 contributes less in strength ( ‹ 10 %).

CEMENT
Hydration Of Cement
 The chemical reaction that takes place between cement and water is referred as
hydration of cement.
 The reaction of cement with water is exothermic.
 During hydration 𝐶3 𝑆 & 𝐶2 𝑆 react with water and calcium silicate hydrate ( C-S-H) gel
is formed along with calcium hydroxide
2𝐶3 𝑆 + 6𝐻 𝐶3 𝑆2 𝐻3 + 3𝐶𝑎(𝑂𝐻)2 + 𝐻𝑒𝑎𝑡
2𝐶2 𝑆 + 4𝐻 𝐶3 𝑆2 𝐻3 + 𝐶𝑎(𝑂𝐻)2 + 𝐻𝑒𝑎𝑡
 More quantity of calcium hydroxide is formed in hydration of 𝐶3 𝑆 in comparison to 𝐶2 𝑆.

CEMENT
Hydration Of Cement
Disadvantages of Calcium Hydroxide
 Calcium hydroxide is not a desirable product in the concrete mass because it is soluble
in water and gets leached out, making the concrete porous, less durable, particularly in
hydraulic structure.
 The calcium hydroxide also reacts with sulphates present in soils and water to form
calcium sulphate which further reacts with 𝐶3 𝐴 and cause disintegration of concrete.
This is known as Sulphate Attack
Advantages of Calcium Hydroxide
 The only advantage is that it is alkaline in nature and it maintains PH value around 13 in
the concrete which resist the corrosion of reinforcement.

CEMENT
Quantity of water required in hydration of cement
 It has been estimated that on an average 23% of water by weight of cement is required
for chemical reaction. This 23% of water chemically combines with cement and
therefore it is called bound water.
 A certain quantity of water is imbided with in the gel course, this water is known as gel
water. It has been estimated that about 15% by weight of cement is required to fill up
the gel course.
 Therefore a total of 38% of water by weight of cement is required for the complete
chemical reaction and occupy the space with in the gel course.

CEMENTTest On Cement
Field test
Colour test
Physical properties test
Lumps test
Strength test
Lab test
Chemical composition test
Standard consistency test
Initial & final setting time
Compressive strength test
Tensile strength test
Soundness test
Fineness test
Specific gravity test
Heat of hydration test

1. Colour Test
The cement should have uniform grey colour with a light greenish shade.
2. Physical Property Test
• The cement should feel smooth when rubbed in between the fingers.
• Throw a small quantity of cement in a bucket of water, it should sink and not float over
the surface.
FEILD TESTS

3. Lumps Test – the sample of the cement should be free from the presence of lumps
which are formed due to the absorbtion of moisture from the atmosphere by the cement.
4. Strength Test – Prepare a block of 25mm x 25mm x 200mm from the given sample of
the cement and immersed it in water for curing for 7 days, remove the block and placed it
over the support that are 150 mm apart. Subject the block to a point load of 340 N. It
should show no sign of failure under the application of this load.

1. Standard Consistency Test
 The test estimate the quantity of
mixing water to form a cement paste
of normal consistency.
 Normal consistency is defined as the
% water requirement of the cement
paste, the viscosity of paste will be
such that the vicat plunger
penetrates up to 33 mm to 53 mm
from the top (5 mm to 7 mm from
bottom) of the vicat mould.
LAB. TESTS

 PROCEDURE
 Take 500 gm of cement and mix it with 24% of water by weight in the first trail.
 Remove all the air voids present in the sample
 Release the 10 mm dia. Plunger gently to allow it to penetrate into the mould and gind
depth of penetration from the top.
 For Ordinary cement, 33 to 35 mm penetration from the top corresponds to standard
consistency of cement
 The % water corresponding to standard consistency is denoted by ‘P’.
 Temperature 27⁰C ± 2⁰C and relative humidity 90%.
LAB TESTS

 Initial and Final setting time
a. A cement paste is prepared with 500 gram of cement + 0.85 times the ‘P’ water (0.85P
water) to prepare the paste.
b. Cement paste is filled in Vicat apparatus
c. 1 sqmm needle is lowered gently and penetration is recorded.
d. Procedure is repeated until the needle fails to penetrate the mould by about 5 mm to 7
mm measured from the bottom of the mould.
e. Time period between the time when water was added to prepare the paste and whe
needle fails to penetrate the mould by 5 mm to 7 mm from bottom is taken as initial
setting time.
LAB. TESTS

 Initial and Final setting time
e. Now the needle is replaced by a needle with 5 mm diameter annular collar.
f. Time interval when the centre needle makes an impression on the sample but annular
collar fails to give impression to the same cement paste, is taken as the final setting time.
LAB. TESTS
 For OPC –
Initial Setting Time = 30 min
Final Setting Time = 10 hours

1. Soundness Test
 Purpose of this test is to detect change in volume of cement after setting.
 Soundness can be measured by following test
I. Le-Chatelier’s test
II. Auto-clave
LAB. TESTS

1. Soundness Test
 Le-Chatelier’s Test
o Apparatus
 Apparatus of this test consist a
split cylinder of 30 mm diameter
and 30 mm height, having a split
of size 0.5 mm along the length of
cylinder
 Indicator arms of 160 mm are
placed on either side of split to
measure the size of the split.
LAB. TESTS

1. Soundness Test
o Procedure
 Cement paste is prepared with 100 gram of cement sample + 0.78P of water.
 A mould of 30mm diameter and 30mm height is placed on glass plate and it is
filled with cement paste.
 Now mould is covered with another glass plate and small weight is placed on
this glass plate.
 Mould is than submerged in the water at temperature of 27⁰C to 32⁰C for 24
hours. After 24 hours mould is taken out at and the distance saperating the
indicator arms is measured.
LAB. TESTS

1. Soundness Test
o Procedure
 Mould is again submerged in water and water is now in boiled condition for 3
hours. Mould is removed from water and the distance between the indicator
arms is measured again.
 Difference between these two measurements represent the soundness of
cement.
LAB. TESTS
 For OPC, Rapid hardening cement, PPC, this value is limited to
10 mm whereas for sulphate cement, high alumina cement, this
value should not exceed 5 mm

1. Soundness Test
 Auto-Clave Test
 This method calculate soundness due to lime and magnesia.
 In this test a mould of 25 mm is prepared (cube) and placed in Autoclave.
 Steam pressure is raised in the autoclave such that gauge pressure of 21
kg/sqcm is attained in 1 hour which is maintained for next 3 hours.
 Remove the sample and measure the change in dimension.
LAB. TESTS
 For OPC, the change in any dimension should not be greater than
0.8%.
 i.e. 25 ×
0.8
100
= 0.2 𝑚𝑚, therefore, Final dimension ≥
25.2 mm

2. Strength Test
 Standard Compressive Strength test
 A Sample of cement (185 gm) is mixed with standard sand (555 gm) in proportion of
1:3 by weight is mixed for 1 minute and then water
𝑃
4
+ 3.5 % is added and mixed
until the paste becomes uniform colour.
 Mould is filled completely with cement paste and is placed on the vibration table for
compaction.
 3 specimen cubes are prepared of size 70.6 mm.
 After 24 hours cubes are removed from the mould and submerged in cleaned water
for desired days.
 Load is applied on the cube in UTM until the specimen fails.
 Compressive strength is calculated from the crushing load divided by average area
LAB. TESTS

2. Strength Test
 Standard Compressive Strength test
LAB. TESTS
 NOTE
≈ 50% of 28 day
strength
≈ 2/3 of 28 days
strength
3 days ( 𝑁 𝑚𝑚2
) 7 days ( 𝑁 𝑚𝑚2
) 28 days ( 𝑁 𝑚𝑚2
)
OPC 33 grade 16 23 33
OPC 43 grade 23 33 43
OPC 53 grade 27 37 53
PPC 16 23 33

2. Strength Test
 Tensile Strength test
There is no test to measure the tensile strength of the cement
directly.
o Procedure
 Briquette method is the indirect method to measure the tensile
strength of the cement.
 Mixture of cement and sand is prepared in 1:3 at % of water is
𝑃
5
+ 2.5 %
 In this test 12 numbers of standard briquette are prepared to
measure the tensile strength of cement.
LAB. TESTS

2. Strength Test
 Tensile Strength test
o 𝑇𝑒𝑛𝑠𝑖𝑙𝑒 𝑠𝑡𝑟𝑒𝑛𝑔𝑡ℎ =
𝑇𝑒𝑛𝑠𝑖𝑙𝑒 𝑓𝑜𝑟𝑐𝑒 𝑎𝑡 𝑓𝑎𝑖𝑙𝑢𝑟𝑒
𝐶𝑟𝑜𝑠𝑠 𝑠𝑒𝑐𝑡𝑖𝑜𝑛 𝑎𝑟𝑒𝑎
=
25.4 ×25.4 𝑚𝑚2
=
6.45 𝑐𝑚2
LAB. TESTS

3. Specific Gravity Test
 Specific gravity of cement is obtained by
using “Le-chatelier’s flask.
 In this method either kerosene or napthene
having specific gravity not less than 0.73 is
used.
LAB. TESTS
 Specific gravity of cement solid =
3.15

4. Fineness Test
 Fineness of the cement is tested in order to check its extent of grinding that directly effect
the rate of hydration, rate of gain of strength and rate of evolution of heat.
 Fineness of the cement can be tested by any of the following method:-
a. Sieve test (using 90 µ sieve)
b. Air permeability test. (Nurse and Blain test)
c. Sedimentation method.
LAB. TESTS

4. Fineness Test
a. Sieve test (using 90 µ sieve)
 100 g of cement sample is taken & lumps in the sample are broken fingers.
 Sample is placed on a 90 µ sieve & continuously sieve for 15 min & note the weight of the
residue left over the sieve after the test.
LAB. TESTS
 For OPC the % weight residue should
not be more than 10%.

4. Fineness Test
b. Air permeability test no. 2250
 This method of test covered the procedure for determining the fineness of the cement that
is represented as specific surface area.
Specific surface area =
𝑇𝑜𝑡𝑎𝑙 𝑠𝑢𝑟𝑓𝑎𝑐𝑒 𝑎𝑟𝑒𝑎
𝑢𝑛𝑖𝑡 𝑤𝑒𝑖𝑔ℎ𝑡
Unit – (
𝑚2
𝑘𝑔
) or (
𝑐𝑚2
𝑔𝑚
)
 The principle of this test is based on the relationship between flow of air through the
cement bed and the surface area of the cement particles forming the cement bed.
LAB. TESTS
 For OPC, 𝑆𝑆𝐴 ≮ 225
𝑚2
𝑘𝑔

5. Heat of Hydration Test
 Heat of hydration of cement is measured by Calorimeter.
LAB. TESTS
 𝐶3 𝐴 865
𝑗
𝑔𝑚
> 𝐶3 𝑠 500
𝑗
𝑔𝑚
> 𝐶3 𝐴𝐹 420
𝑗
𝑔𝑚
> 𝐶2 𝑆 260
𝑗
𝑔𝑚
Rate of hydration
𝐶3 𝐴𝐹 > 𝐶3 𝐴 > 𝐶3 𝑆 > 𝐶2 𝑆

6. Chemical Composition Test
 Ratio of alumina to that of iron oxide should no be less than 0.6
𝐴𝑙2 𝑂3
𝐹𝑒2 𝑂3
≮ 0.66
 Lime saturation ratio
0.66 <
𝐶𝑎𝑂 − 0.7𝑆𝑂3
2.8𝑆𝑖𝑂2 + 1.2𝐴𝑙2 𝑂3 + 0.65𝐹𝑒2 𝑂3
< 1.02
 Total sulphur content not be greater than 2.75%
 Weight of magnesia(MgO) ≯ 5%
 % of Insoluble residue ≯ 1.5%
LAB. TESTS

CEMENT
Types Of Cement
• Ordinary
Portland
Cement
• RHC
• Extra RHC
• Quick Setting Cement
• Sulphate resisting cement
• Super Sulphate Cement
• Portland Slag Cement
• PPC
• High Alumina
Cement
• Hydrophobic
cement
• IRS T-40
Cement

CEMENTTypes Of Cement
1. Ordinary Portland cement
 Prepare yourself

2. Rapid Hardening cement
 This cement achieve high rate of development of strength it should not be confused with
quick setting cement which only sets quickly.
 The early strength of this cement is because of higher % of 𝐶3 𝑆 (approx. 56%) and lower % of
𝐶2 𝑆.
 This cement attains strength at the age of 3 days, equivalent to the strength of OPC at 7 days.
 Uses
 Emergency repair works
 In rigid pavement construction
 Where formwork is to be remove early to ensure further construction.
 In cold weather condition where rate of hydration is slow due to low temperature.

3. Extra Rapid Hardening cement
 It is manufactured by integrating of RHC clinkers with 2% 𝐶𝑎𝐶𝑙2.
 This cement achieve 25% more strength than RHC in 1 day and 10 to 20% more strength tha
RHC in 7 days
 Uses
 This cement is not used these days because it is seen that chlorine creates cracks.

4. Quick Setting Cement
 This cement is produced by mixing a small quantity of 𝐴𝑙2(𝑆𝑂4)3 in fine grinding cement &
increasing the 𝐶3 𝐴 and reducing the cement
 Initial setting time is 5 minutes and final setting time is 30 minutes.
 Uses
 Construction in stagnant and running water.

5. Sulphate Resisting Cement
 This cement is produced by reducing the proportion of calcium aluminate (𝐶3 𝐴 𝑎𝑛𝑑 𝐶4 𝐴𝐹).
 This cement has resistance against sulphate attack.
 Uses –
 Marine structures
 Sewage treatment plant
 Foundation and basement in the soil having higher concentration of sulphate.

6. Super Sulphate Cement
 This cement is manufactured by integrating of 80 to 85% slag (residue of iron industry), 10 to
15 % gypsum & 5% of cement clinker.
 This cement is more resisting to the attack of sulphate than sulphate resisting cement.
 Uses –

7. Portland Slag Cement
 It is manufactured by mixing the cement clinker with blast furnace slag & gypsum in pre
determined proportion.
 This cement is low heat cement which has relatively more resistance against sulphate attack. It
gains strength with time.
 It offers less permeability and this cement is also cheap
 Uses –
 In construction of hydraulic structures.

8. Portland Pozzolona Cement
 In pozzolonic material cilicious or aluminous compounds are present which do not have its
own cementing properties but in presence of water it reacts with 𝐶𝑎(𝑂𝐻)2 (release during
hydration of cement) and form cementing material (C-S-H gel).
𝐶𝑒𝑚𝑒𝑛𝑡 + 𝑤𝑎𝑡𝑒𝑟 → 𝐶 − 𝑆 − 𝐻 𝑔𝑒𝑙 + 𝐶𝑎 𝑂𝐻 2 + ℎ𝑒𝑎𝑡
𝑃𝑜𝑧𝑧𝑜𝑙𝑜𝑛𝑖𝑐 𝑚𝑎𝑡𝑒𝑟𝑖𝑎𝑙 + 𝐶𝑎(𝑂𝐻)2 + 𝐻2 𝑂 → 𝐶 − 𝑆 − 𝐻 𝑔𝑒𝑙
 Examples of pozzolonic material – Fly ash, Rice Husk, Meta Kaoline (type of clay)
 PPC is manufactured by integrating of OPC clinker with 10% to 30% of pozzolonic material.
 Properties –
 It is a low heat cement.
 This cement is more resisting against sulphate attack.
 It offers less permeability.
 This cement is more plastic and workable in compare to OPC.

9. Low Heat Cement
 This cement is produce by reducing the % of 𝐶3 𝐴 & 𝐶3 𝑆 and corresponding increasing the
% of 𝐶2 𝑆 ( Nearly 46 %)
 The rate of development of strength is low but 28 days strength is same as OPC.
 Uses
 Mass Concreting (dams, foundation walls, piles etc.)

10. High Alumina Cement
 This cement is manufactured by grinding Bauxite ( this contain aluminium > 32%) & the
ratio of alumina to lime must be in the range of 0.85 to 1.3
 Initial setting time = 3.5 hours
Final setting time = 5 hours
Hence in this cement we can take more time to place the cement and less time to remove
the form work.
 This cement is more resistant against the attack of sulphate.
 Uses – it evolve great heat during setting hence not affected by frost action.

11. Hydrophobic Cement
 This cement is manufactured by integrating the OPC clinker with oleic acid and steric acid.
 These acids forms a water repellent film which reduces the tendency of cement particles to
absorb moisture from atmosphere.
 Uses – where it is required to store the cement for long duration.

12. IRS T-40 Cement
 It is specified type of cement in which higher % of 𝐶3 𝑆 is ensured to develop high early
strength.
 Used in manufacturing the concrete sleepers for Indian Railways.

Cement

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