Concrete is a mixture of cement, sand, gravel, and water that hardens into a building material. It is the second most consumed substance on Earth after water. Concrete is made by mixing cement and water to form a paste that is then mixed with fine and coarse aggregates. The paste coats the surface of the aggregates and binds them together into a rock-like mass once hardened. Concrete's strength comes from reinforcement like steel bars for buildings and structures.

1. Introduction of Concrete
Mr. Kiran R. Patil
Assistant Professor,
Department of Civil Engineering,
D. Y. Patil College of Engineering & Technology,
Kolhapur

2. What is Concrete?
• Concrete is the most commonly used construction material. It is the most widely-used
material on our planet after water.
• We use more concrete today than steel, wood, plastics, and aluminum combined.
• Basically, concrete is just a bunch of rubble mixed with water and cement.
• Together, these ingredients form rocky jelly that can be poured into a mould to get
desired shape.
• Thus it is sometimes called liquid stone or artificial stone. The mixture when placed in
forms and allowed to cure hardens into rock-like mass.
• The hardening is caused by chemical reaction between water and cement. This reaction
continues for a long time and thus, the concrete becomes stronger with age.
• The voids of coarse aggregate are filled by fine aggregate and the voids of fine
aggregate are filled with cement paste.
• The water-cement paste also coats the surface of fine and coarse aggregates and binds
them together in a compact mass.
• Hardened concrete is strong in compression but weak in tension. To overcome this
weakness, steel bars (reinforcement) are introduced in it. Such type of concrete is called
Reinforced Cement Concrete (R.C.C.).

3. • Concrete is obtained by mixing cement, fine aggregate (sand), coarse aggregate (metal)
and water in required proportions.
• A number of additives (admixtures) are available which are useful in construction of
highways, flyovers, dams, runways or buildings.
• There are additives that increase concrete’s electrical conductivity, strength, durability,
ductility, and resistance to acid corrosion.
• There are chemical retarders that slow concrete’s hydration, accelerators that speed it
up, and plasticizers that increase its workability. There are corrosion inhibitors. There
are pigments. There are decorative stones and seashells.
• Manufacture of good concrete is indeed a challenging job. The quality of concrete
greatly depends on the workmanship, as quality of cement and aggregates is generally
assured.
• A good concrete must satisfy the three basic requirements,
(i) it must be workable enough in fresh state while being transported and placed in the
formwork,
(ii) it must be strong enough in hardened sate,
(iii) it must be sufficiently durable in hardened state.

4. 1. Cement
• Cement is finely ground material having adhesive and cohesive properties which is
used as binding material for the ingredients of cement concrete
• Joseph Aspdin, a British bricklayer invented cement in 1824. He called it Portland
cement because when it hardened, it produced a solid mass which was similar to the
stone from the quarries near Portland in U.K.
• Cement is obtained by burning a mixture of calcareous (containing lime) and
argillaceous (containing alumina) materials at about 1500°C. The product of
burning is called clinker. Clinker is then cooled and ground to the required fineness
to produce cement. Gypsum (CaSO4) is added during grinding to adjust the setting
time. The amount of gypsum is about 3 to 5% by weight of the clinker. If gypsum is
not added, the cement would set as soon as water is added to it. Gypsum slows
down the setting action of cement.
• For general construction, Ordinary Portland Cement (O.P.C.) is used. O.P.C. is
available in two grades – 43 Grade and 53 Grade
• 43 Grade O.P.C. means, the minimum compressive strength of cement after 28 days
is 43 N/mm².
• Portland Pozzolana Cement (P.P.C) is becoming popular these days.
• For special purposes other cements like Quick Setting Cement, Sulphur Resisting
Cement, Rediset Cement, Low Heat Cement, etc. are used.

5. Manufacture of Cement
• There are two processes depending upon whether the mixing and grinding of raw
material is done in wet or dry conditions,
• Wet Process (Old Method)
• Dry Process (Modern Method)
• The dry process has become popular because it requires less fuel as the materials are
in a dry state, whereas in the wet process the slurry contains about 35 to 50% water.
More fuel is required to dry the slurry. In India most of the cement factories are using
the dry process.
• Dry Process:
• The raw materials (calcareous and argillaceous) are first reduced in size to about 25
mm in crushers.
• These materials are dried by passing a current of dry air.
• These dried materials are then pulverized into fine powder in ball mills.
• These operations are done separately for each raw material and they are stored in
separate hoppers.
• The raw materials are then mixed in correct proportions and made ready for feeding
the rotary kiln. This is called the raw meal which is stored in storage tanks.
• The raw meal is then burnt in rotary kiln at about 1500°C.

6. • After burning, the raw meal gets converted into small hard greenish balls called
clinker.
• Clinker are then cooled and finely ground in ball mills.
• During grinding, 3 to 5% Gypsum is added to control the initial setting time of
cement.
• This cement is then taken to storage silos from where it is filled in 50 kg bags.
• Flow Diagram of Dry Process
Calcareous Material (Limestone) Argillaceous Material (Clay/ Shale)
Crusher
Raw Meal Silo
Rotary kiln
Cooler
Clinker Silo
Clinker Silo
Add Gypsum 2-3% Ball Mill

7. • Chemical Composition of Cement
• Role of oxides in cement:
• Lime (CaO): It is responsible for strength. Excessive lime makes the cement unsound
i.e. expansion would be more.
• Silica (SiO2): It imparts strength but excessive silica makes the cement difficult to
fuse and form clinker.
Cement Silo
Packing Unit
Oxide Percentage
Lime CaO 60 - 67
Silica SiO2 17 - 25
Alumina Al2O3 3 - 8
Iron oxide Fe2O3 0.5 - 6
Magnesia MgO 0.1 - 4
Sulphur trioxide SO3 1 - 3
Alkalis Na2O + K2O 0.2 – 1.3

8. • Alumina (Al2O3): It gives early strength to cement.
• Iron oxide (Fe2O3): It gives typical gray colour to cement. It acts as catalyst and helps
in burning process.
• Magnesia (MgO): Excess magnesia causes unsoundness.
• Bogue’s Compounds:
• The oxides present in the raw material when subjected to high temperature, combines
with each other to form complex compounds called Bogue’s compounds.
• Role of constituents of cement:
• The combined content of C3S and C2S is about 70 to 80% of the cement. The
average content of C3S is 45% and that of C2S is 25%. They control most of the
strength properties.
• C3S reacts very fast with water. It evolves great amount of heat and develops early
strength. Thus, cement with high C3S content is better for cold weather concreting.
Sr.No. Name of
Compound
Formula Abbreviated
Formula
Percentage
1 Tricalcium Silicate 3CaO.SiO2 C3S 30 - 50
2 Dicalcium Silicate 2CaO.SiO2 C2S 20 - 45
3 Tricalcium
Aluminate
3CaO.Al2O3 C3A 8 - 12
4 Tetra calcium
Aluminoferrite
4CaO.Al2O3.Fe2O3 C4AF 6 - 10

9. • C2S is responsible for later age strength of concrete. It hydrates slowly and evolves
comparatively less heat of hydration than C3S. C2S provides resistance to chemical
attack.
• C3A reacts quickly with water and may cause immediate stiffening of paste (flash
set). To prevent this flash set, gypsum is added during the manufacture of cement.
C3A speed up the hardening of concrete. Thus, C3A content is increased for
producing rapid hardening cement. C3A evolves greater heat of hydration.
• C4AF also hydrates rapidly. Its contribution to strength is quite less. C4AF gives
resistance to the attack of alkalis and sulphates.

10. • Properties of Cement / Testing of Cement:
• Field Tests:
1. There should not be any visible lumps.
2. The colour should be uniformly greenish grey.
3. When hand is inserted in a cement bag, it should feel cool.
4. Cement should be smooth when touched or rubbed in between fingers.
5. If a handful of cement is thrown into a bucket full of water, it should float for some time
before sinking.
6. Take about 100 gm of cement and a small quantity of water and make a stiff paste. Make
a cake with this paste having sharp edges. Put it on a glass plate and slowly take it under
water in a bucket. After 24 hours, the cake should retain its original shape and it should
attain some strength.
• Laboratory Tests:
1. Fineness test
2. Setting time test
3. Compressive strength test
4. Soundness test
5. Heat of hydration test
6. Chemical composition test

11. 1. Fineness Test:
• Fineness of cement is tested by two methods,
• By sieving
By sieving: This test is conducted by sieving 100 gm of cement on 90 microns IS sieve.
The residue left on the sieve shall not be more than 10gm (10 %).
% fineness= (weight of cement retain on 90 microns sieve/ Total weight of cement)*100

12. 2. Standard Consistency Test

13. • For finding out initial setting time, final setting time, soundness and compressive
strength of cement, it is necessary to determine the water content required to produce the
paste of standard consistency.
• The consistency is measured by using Vicat apparatus. The standard consistency of a
cement paste is defined as that consistency which will permit a Vicat plunger having 10
mm diameter and 50 mm length to penetrate a depth of 5 to 7 mm from the bottom of the
mould as shown in the figure.
• A trial paste of cement and water is mixed in a prescribed manner and placed in the Vicat
mould having 40 mm depth.
• The plunger is then brought into contact with the top surface of the mould and released.
Under the action of weight of the rod, the plunger will penetrate the paste.
• This is considered to be standard as per IS: 4031-1988, when the plunger penetrates the
paste to a depth of 5 to 7 mm from the bottom of the mould.
• The water content of the standard paste is expressed as a percentage by mass of the dry
cement. It is denoted by ‘P’. The usual range of standard consistency is 26 to 33%.

14. 3. Setting Time Test
• Initial setting time is the time elapsed between the moment at which water is added to
the cement and the time when the paste starts losing its plasticity.
• Final setting time is the time elapsed between the moment at which water is added to
cement and the time when at which the paste has completely lost its plasticity and has
attained sufficient firmness.
• In actual construction, certain time is required for mixing, transporting and placing of
concrete or mortar. During this period, the cement paste should remain in plastic
condition.
• Normally, a minimum time of 30 minutes is given for mixing and handling operations.
Once the concrete is placed in the final position, compacted and finished, it should lose
its plasticity in the earliest possible time so that it will not be damaged by external
agencies. This time should not be more than 600 minutes (10 hours).
• Setting times are tested by using Vicat apparatus with appropriate needles.
❖ Initial setting time test:
• For conducting this test, cement paste is prepared by adding 0.85P water to the dry
cement and the mould is filled with it. The initial setting time needle (c/s area 1 sq.mm)
is attached to the apparatus and penetrations are noted at intervals.
• The time period elapsed between the moment at which water is added to the cement and
the moment at which the needle penetrates the test block to a depth of 5 ± 0.5 mm from
the bottom of the mould is considered as initial setting time.

15. • Final setting time test:
• Once the initial setting time is obtained, the needle is replaced with final setting time
needle. The impressions of the needle on the test block are observed at intervals. Final
setting time is defined as the period elapsed between the moment at which water is
added to the cement and the time at which the needle makes an impression on the test
block while the circular attachment fails to do so.
• I.S. specifications for initial and final setting time:
Type of cement Initial setting time
(minimum)
Final setting time
(maximum)
O.P.C. 43 and 53 Grade 30 minutes 600 minutes
P.P.C. 30 minutes 600 minutes
Rapid hardening cement 30 minutes 600 minutes
Low heat cement 60 minutes 600 minutes

16. 4. Compressive strength test
• The compressive strength of cement is the most important property. Strength tests are
not conducted on neat cement because of the difficulties of shrinkage and cracking of
neat cement paste.
• Strength of cement is indirectly found on cement-sand mortar in 1:3 proportions. The
standard sand is used for making this mortar.
• For one cube, take 555 gm of standard sand, 185 gm of cement in a non-porous tray and
mix them with a trowel for one minute.
• Then add water quantity (
𝑷
𝟒
+ 3) % of combined weight of cement and sand.
• Mix the three ingredients thoroughly. This mortar is immediately filled in the cube
mould of size 70.6 mm X 70.6 mm X 70.6 mm.
• The area of the face of the cube will be equal to 5000 mm². Compact the mortar in the
cube by hand compaction or by using table vibrator for 2 minutes.
• Keep the compacted cube in the mould at a temperature 27 ± 2°C and 90% relative
humidity for 24 hours.
• After 24 hours, the cubes are removed from the mould and immersed in clean fresh
water until taken out for testing.
• Three cubes are tested for compressive strength at the periods of 3, 7 and 28 days.
• The periods are considered from the completion of vibration. The compressive strength
will be the average of the strengths of the three cubes for each period respectively.

17. • Compressive strength of various cements:
Type of cement
Compressive strength in N/mm² (minimum)
1 day 3 days 7 days 28 days
O.P.C. 43 Grade - 23 33 43
O.P.C. 53 Grade - 27 37 53
P.P.C. - 16 22 33
Rapid hardening cement 16 27 - -
Low heat cement - 10 16 35
5. Soundness Test

18. • Unsoundness of cement means its undesirable expansion, which may cause severe
cracking of concrete or mortar. Unsoundness of cement is due to the presence of
excessive lime.
• The soundness test is conducted by using Le Chatelier apparatus as shown in the
figure.
• 100 gm cement is mixed with 0.78P water to make a paste of standard consistency.
• The mould is placed on a glass plate and filled with the prepared paste.
• The mould is covered on the top by another glass plate.
• The whole assembly is immersed in water for 24 hours.
• The assembly is taken out and the distance between the indicator points is measured.
• The assembly is again submerged in water. The water is kept boiling for 3 hours.
• The mould is then removed from the water, allowed to cool and the distance between
the indicator points is measured.
• The difference between these two readings should not be more than 10 mm.
Otherwise, the cement is unsound.

19. 6. Heat of hydration test
• This test is essential for low heat cement only. This test is carried out over a few days by
vacuum flask method, or over a longer period in an adiabatic calorimeter. The heat of
hydration of low heat cement should not be more than 65 cal/gm at 7 days and 75
cal/gm at 28 days.
• Hydration of cement
• As soon as water is added to cement, setting and hardening begins due to chemical
reaction between water and cement constituents. The reaction by virtue of which cement
becomes a binding agent is known as hydration.
• When water is added to cement, the quickest to react with water is C3A and in the order
of decreasing rate are C4AF, C3S and C2S.
• The silicates and aluminates in cement form products of hydration which in time
produce a firm and hard mass. The hydration process is not instantaneous one. The
reaction is faster in the early period and continues indefinitely at a decreasing rate.
• The first to react is C3A and the reaction is violent and lead to immediate stiffening of
the paste. This is known as flash set. To prevent this, gypsum is added to cement clinker.
• C3S reacts with water and produce more heat of hydration. It is responsible for early
strength development.
• C2S hydrates slowly. After 28 days, the hydration of C3S comes to an end and the
hydration of C2S just begins at that time. Hence, when a high strength is required within
a short time, cement is made with high C3S content. If high strength is required at a later
age, cement is made with high C2S.

20. • Hydration starts at the surface of cement particles. Thus the rate of hydration depends upon
fineness of cement. More finer the cement, higher is the rate of hydration.
• Products of hydration:
• During the chemical reaction of C3S and C2S with water, calcium silicate hydrate (C-S-H)
and calcium hydroxide Ca(OH)2 are formed. C-S-H determines good properties of concrete.
2 C3S + 6H C3S2H3 + 3Ca (OH)2
2 C2S + 4H C3S2H3 + Ca (OH)2
• C3A and C4AF together form calcium aluminate trisulphate hydrate (C6AS3H32) and
calcium aluminate monosulphate hydrate (C4ASH18).
• Heat of hydration:
• The reaction of cement with water is exothermic. The reaction liberates a considerable
quantity of heat. This liberated heat is called heat of hydration. Normal cement produces
about 90 cal/gm in 7 days and about 100 cal/gm in 28 days.
• The early heat of hydration is mainly contributed from the hydration of C3S. Fineness also
affects the heat of hydration. High rate of heat liberation may be controlled by reducing the
proportions of compounds that hydrate more rapidly i.e. C3S and C4AF.
• Concrete acts as an insulator due to its low conductivity. In the interior of large concrete
mass, hydration can result in a large rise in temperature. At the same time, the exterior of
the concrete mass loses some heat causing development of steep temperature gradient.
During subsequent cooling of the interior, serious cracking may occur.
• Sometimes, the heat of hydration is advantageous. It prevents freezing of water in the
capillaries and pores of freshly placed concrete in cold weather.

21. ❖ Types of Cement
1. Ordinary Portland Cement (O.P.C.):
• O.P.C. is most widely used cement.
• O.P.C. is classified into three grades – 33 Grade, 43 Grade and 53 Grade depending upon
the compressive strength at 28 days.
• Due to popularity of higher grade cements, 33 grade cement is out of market.
• It has been possible to upgrade the qualities of cement by using high quality lime stone,
modern equipment's, closer control on constituents, maintaining better particle size
distribution, finer grading & better packing.
• Use of higher grade cements offer many advantages for making stronger concrete.
• Although they are little costlier than low grade cement, they offer 10 to 20% saving in
cement consumption. They also develop strength at faster rate.
• The manufacturing of OPC is decreasing all over the world in view of the popularity of
blended cement on account of lower energy consumption, environmental pollution,
economic & other technical reasons.
2. Rapid Hardening Cement (IS: 8041 – 1990):
• This cement is similar to OPC. As the name indicates it develops strength rapidly & as
such as it may be more appropriate to call it as high early strength cement.
• Rapid hardening cement develops strength at the age of three days, the same strength as
that is expected of OPC at seven days.
• The rapid rate of development of strength is attributed to the higher fineness of grading,
higher C3S ( Tri-calcium silicate) & lower C2S ( Dri-calcium silicate) content.
• A higher fineness of cement particles expose greater surface area for action of water &
also higher proportion of C3S results in quicker hydration.

22. • Rapid hardening cement gives out much greater heat of hydration during the early
period.
• Therefore, rapid hardening cement should not be used in mass concrete construction.
• Uses:
➢ In pre-fabricated concrete construction
➢ Where formwork is to be removed early for re-use
➢ Concrete repair works
➢ In cold weather concreting
3. Sulphate Resisting Cement (IS: 12330 – 1988):
• OPC is susceptible to the attack of sulphates, in particular to the action of magnesium
sulphate.
• Sulphates react both with the free calcium hydroxide in set cement to form calcium
sulphate & with hydrate of calcium aluminate to form calcium sulphoaluminates, the
volume which is approximately 227% of the volume of the original aluminates.
• Their expansion within the formwork of hardened cement paste results in cracks &
subsequent disruption.
• Sulphate attack is greatly accelerated if go along with alternate drying & wetting which
normally takes place in marine structures in the zone of tidal variations.
• To reduce the sulphate attack, the use of cement with low C3A content is found to be
effective. Such cement with low C3A and comparatively low C4AF content is known as
Sulphate Resisting Cement. In other words, this cement has a high silicate content.
• The specification generally limits the C3A content to 5 per cent. Tetracalcium Alumino
Ferrite (C3AF) varies in Normal Portland Cement between to 6 to 12%.

23. • Since it is often not feasible to reduce the Al2O3 content of the raw material, Fe2O3
may be added to the mix so that the C4AF content increases at the expense of C3A. IS
code limits the total content of C4AF and C3A, as 2C3A + C4AF should not exceed
25%
• The use of sulphate resisting cement is recommended under the following conditions:
a) Concrete to be used in marine condition;
b) Concrete to be used in foundation and basement, where soil is infected with sulphates;
c) Concrete used for fabrication of pipes which are likely to be buried in marshy region or
sulphate bearing soils;
d) Concrete to be used in the construction of sewage treatment works.
4. Portland Pozzolana Cement (P.P.C.) (IS: 1489 – 1991):
• P.P.C. is manufactured by grinding of O.P.C. clinker with 15 to 35% of pozzolanic
material like fly ash.
• Fly ash is a waste material generated in thermal power stations where powdered coal is
used as a fuel. A pozzolanic material is siliceous or aluminous material which has no
cementaceous properties. This material reacts with calcium hydroxide to form
compounds possessing cementaceous properties.
Ca (OH) 2 + Pozzolana + Water = C-S-H gel
• P.P.C. produces less heat of hydration and offers resistance to chemical attack.
• It is useful for mass concreting, hydraulic structures and marine structures.
• P.P.C. is economical as costly clinker is replaced by cheaper pozzolanic material.
• The rate of development of strength is slightly slower than O.P.C.

24. 5. Low Heat Portland Cement (IS: 12600 – 1989):
• It is well known that hydration of cement is an exothermic action which produces large
quantity of heat during hydration.
• Formation of cracks in large body of concrete due to heat of hydration has focussed the
attention of the concrete technologists to produce a kind of cement which produces less heat
or the same amount of heat, at a low rate during the hydration process.
• Cement having this property was developed in U.S.A. during 1930 for use in mass concrete
construction, such as dams, where temperature rise by the heat of hydration can become
excessively large.
• A low-heat evolution is achieved by reducing the contents of C3S and C3A which are the
compounds evolving the maximum heat of hydration and increasing C2S.
• A reduction of temperature will delay the chemical action of hardening and so further
restrict the rate of evolution of heat.
• The rate of evolution of heat will, therefore, be less and evolution of heat will extend over a
longer period. Therefore, the feature of low-heat cement is a slow rate of gain of strength.
• But the ultimate strength of low-heat cement is the same as that of ordinary Portland
cement.
• As per the Indian Standard Specification the heat of hydration of low-heat Portland cement
shall be as follows:
7 days — not more than 65 calories per gm.
28 days — not more than 75 calories per gm
• The 7 days strength of low heat cement is not less than 16 MPa in contrast to 22 MPa in the
case of ordinary Portland cement. Other properties, such as setting time and soundness are
same as that of ordinary Portland cement.

25. 6. High Alumina Cement (IS: 6452 – 1989):
• High alumina cement is obtained by fusing or sintering a mixture, in suitable proportions, of
alumina and calcareous materials and grinding the resultant product to a fine powder.
• The raw materials used for the manufacture of high alumina cement are limestone and
bauxite.
• These raw materials with the required proportion of coke were charged into the furnace.
• The furnace is fired with pulverised coal or oil with a hot air blast. The fusion takes place
at a temperature of about 1550-1600°C.
• The cement is maintained in a liquid state in the furnace. Afterwards the molten cement is
run into moulds and cooled.
• These castings are known as pigs. After cooling the cement mass resembles a dark, fine
grey compact rock resembling the structure and hardeness of basalt rock.
• The pigs of fused cement, after cooling are crushed and then ground in tube mills to a
fineness of about 3000 sq. cm/gm.
7. Super Sulphated Cement (IS: 6909 – 1990):
• Super sulphated cement is manufactured by grinding together a mixture of 80-85 per cent
granulated slag, 10-15 per cent hard burnt gypsum, and about 5 per cent Portland cement
clinker.
• The product is ground finer than that of Portland cement. Specific surface must not be less
than 4000 cm2 per gm.
• This cement is rather more sensitive to deterioration during storage than Portland cement.
• Super-sulphated cement has a low heat of hydration of about 40-45 calories/gm at 7 days
and 45-50 at 28 days.

26. • This cement has high sulphate resistance. Because of this property this cement is
particularly recommended for use in foundation, where chemically aggressive conditions
exist.
• As super-sulphated cement has more resistance than Portland blast furnace slag cement to
attack by sea water, it is also used in the marine works.
• Other areas where super-sulphated cement is recommended include the fabrication of
reinforced concrete pipes which are likely to be buried in sulphate bearing soils.
• The substitution of granulated slag is responsible for better resistance to sulphate attack.
Super-sulphated cement, like high alumina cement, combines with more water on hydration
than Portland cements. Wet curing for not less than 3 days after casting is essential as the
premature drying out results in an undesirable or powdery surface layer.
• When we use super sulphated cement the water/cement ratio should not be less than 0.5. A
mix leaner than about 1:6 is also not recommended.
8. Coloured Cement (White Cement): (IS: 8042- 1989):
• For manufacturing various coloured cements either white cement or grey Portland cement is
used as a base. The use of white cement as a base is costly. With the use of grey cement
only red or brown cement can be produced.
• Coloured cement consists of Portland cement with 5-10 per cent of pigment. The pigment
cannot be satisfactorily distributed throughout the cement by mixing, and hence, it is usual
to grind the cement and pigment together.
• The properties required of a pigment to be used for coloured cement are the durability of
colour under exposure to light and weather, a fine state of division, a chemical composition
such that the pigment is neither effected by the cement nor damaging to it, and the absence
of soluble salts.

27. • The process of manufacture of white Portland cement is nearly same as OPC. As the raw
materials, particularity the kind of limestone required for manufacturing white cement is
only available around Jodhpur in Rajasthan, two famous brands of white cement namely
Birla White and J.K. White Cements are manufactured near Jodhpur.
• The raw materials used are high purity limestone (96% CaCo3 and less than 0.07% iron
oxide). The other raw materials are china clay with iron content of about 0.72 to 0.8%,
silica sand, flourspar as flux and selenite as retarder.
• The fuels used are refined furnace oil (RFO) or gas. Sea shells and coral can also be used as
raw materials for production of white cement.
• The properties of white cement is nearly same as OPC. Generally white cement is ground
finer than grey cement.
• White cement is used for decorative purposes such as flooring, cladding, special plasters
and finishes, etc.
9. Portland Slag Cement- PSC (IS: 455 - 1989):
• Portland slag cement is obtained by mixing Portland cement clinker, gypsum and granulated
blast furnace slag in suitable proportions and grinding the mixture to get a thorough and
close mixture between the constituents.
• It may also be manufactured by separately grinding Portland cement clinker, gypsum and
ground granulated blast furnace slag and later mixing them very well.
• The resultant product is a cement which has physical properties similar to those of ordinary
Portland cement.
• In addition, it has low heat of hydration and is relatively better resistant to chlorides, soils
and water containing excessive amount of sulphates or alkali metals, alumina and iron, as
well as, to acidic waters, and therefore, this can be used for marine works with advantage.

28. • The major advantages currently recognized are:
(a) Reduced heat of hydration;
(b) Refinement of pore structure;
(c) Reduced permeability;
(d) Increased resistance to chemical attack.
10. Hydrophobic Cement (IS: 8043 - 1991):
• Hydrophobic cement is obtained by grinding ordinary Portland cement clinker with water
repellant film-forming substance such as oleic acid, and stearic acid.
• The water-repellant film formed around each grain of cement, reduces the rate of
deterioration of the cement during long storage, transport, or under unfavorable conditions.
• The film is broken out when the cement and aggregate are mixed together at the mixer
exposing the cement particles for normal hydration.
• The film forming water-repellant material will entrain certain amount of air in the body of
the concrete which incidentally will improve the workability of concrete.
• The transportation and storage of cement in highly humid areas cause deterioration in the
quality of cement. In such places with poor communication system, cement perforce
requires to be stored for long time.
• Ordinary cement gets deteriorated and loses some if its strength, whereas the hydrophobic
cement which does not lose strength is in such situations.
• The properties of hydrophobic cement is nearly the same as that ordinary Portland cement
except that it entrains a small quantity of air bubbles. The hydrophobic cement is made
actually from ordinary Portland cement clinker.

29. • After grinding, the cement particle is sprayed in one direction and film forming materials
such as oleic acid, or stearic acid, or pentachlorophenol, or calcium oleate are sprayed from
another direction such that every particle of cement is coated with a very fine film of this
water repellant material which protects them from the bad effect of moisture during storage
and transportation.
• The cost of this cement is nominally higher than ordinary Portland cement.
11. Masonry Cement (IS: 3466 – 1988):
• Ordinary cement mortar, however good when compared to lime mortar with respect to
strength and setting properties, is inferior to lime mortar with respect to workability, water
retention, shrinkage property and extensibility.
• Masonry cement is a type of cement which is particularly made with such combination of
materials, which when used for making mortar, incorporates all the good properties of lime
mortar and discards all the not so ideal properties of cement mortar.
• This kind of cement is mostly used, as the name indicates, for masonry construction. It
contains certain amount of air-entraining agent and mineral admixtures to improve the
plasticity and water retention.
12. Oil- Well Cement (IS: 8229 – 1986):
• Oil-wells are drilled through stratified sedimentary rocks through a great depth in search of
oil. It is likely that if oil is struck, oil or gas may escape through the space between the steel
casing and rock formation.
• Cement slurry is used to seal off the annular space between steel casing and rock strata and
also to seal off any other fissures or cavities in the sedimentary rock layer.
• The cement slurry has to be pumped into position, at considerable depth where the
prevailing temperature may be upto 175°C.

30. • The pressure required may go upto 1300 kg/cm2. The slurry should remain sufficiently
mobile to be able to flow under these conditions for periods upto several hours and then
hardened fairly rapidly.
• It may also have to resist corrosive conditions from sulphur gases or waters containing
dissolved salts.
• The type of cement suitable for the above conditions is known as Oil-well cement.
• The desired properties of Oil-well cement can be obtained in two ways:
❑ by adjusting the compound composition of cement or by adding retarders to ordinary
Portland cement. The commonest agents are starches or cellulose products or acids. These
retarding agents prevent quick setting and retains the slurry in mobile condition to facilitate
penetration to all fissures and cavities.
❑ Sometimes workability agents are also added to this cement to increase the mobility.
13. Expansive Cement:
• Concrete made with ordinary Portland cement shrinks while setting due to loss of free
water. Concrete also shrinks continuously for long time. This is known as drying shrinkage.
• Cement used for grouting anchor bolts or grouting machine foundations or the cement used
in grouting the prestress concrete ducts, if shrinks, the purpose for which the grout is used
will be to some extent defeated.
• There has been a search for such type of cement which will not shrink while hardening and
thereafter. As a matter of fact, a slight expansion with time will prove to be advantageous
for grouting purpose.
• This type of cement which suffers no overall change in volume on drying is known as
expansive cement.
• Cement of this type has been developed by using an expanding agent and a stabilizer very

31. carefully.
• Proper material and controlled proportioning are necessary in order to obtain the desired
expansion.
• Generally, about 8-20 parts of the sulphoaluminate clinker are mixed with 100 parts of the
Portland cement and 15 parts of the stabilizer.
• Since expansion takes place only so long as concrete is moist, curing must be carefully
controlled. The use of expanding cement requires skill and experience.
14. Rediset Cement:
• Accelerating the setting and hardening of concrete by the use of admixtures is a common
knowledge. Calcium chloride, lignosulfonates, and cellulose products form the base of
some of admixtures.
• The limitations on the use of admixtures and the factors influencing the end properties are
also fairly well known.
• High alumina cement, though good for early strengths, shows deterioration of strength
when exposed to hot and humid conditions.
• A new product was needed for use in the precast concrete industry, for rapid repairs of
concrete roads and pavements, and slip-forming.
• Properties of “Rediset”
(i) The cement allows a handling time of just about 8 to 10 minutes.
(ii) The strength pattern is similar to that of ordinary Portland cement mortar or concrete after
one day or 3 days. What is achieved with “Rediset” in 3 to 6 hours can be achieved with
normal concrete only after 7 days.
(iii) “Rediset” releases a lot of heat which is advantageous in winter concreting but excess heat
liberation is harmful to mass concrete.

32. (iv) The rate of shrinkage is fast but the total shrinkage is similar to that of ordinary Portland
cement concrete.
(vi) The sulphate resistance, is very poor.
• Applications :
(a) very-high-early (3 to 4 hours) strength concrete and mortar,
(b) patch repairs and emergency repairs,
(c) quick release of forms in the precast concrete products industry,
(d) slip-formed concrete construction,
(e) construction between tides

33. Physical properties of various types of cement:
Sr.
No.
Type of Cement
Fineness
(m²/kg)
Minimum
Soundness
(mm)
Maximum
SettingTime
Compressive Strength
(N/mm²) Minimum
Initial
(minutes)
Minimum
Final
(minutes)
Maximum
3 Days 7 Days 28 Days
1
43 Grade O.P.C.
IS 8112 -1989 225 10 30 600 23 33 43
2
53 Grade O.P.C.
IS 12269 -1987 225 10 30 600 27 37 53
3
Rapid Hardening
IS 8041 - 1990 325 10 30 600 16 27 N.S.
4
S.R.C.
IS 12330 - 1988 225 10 30 600 10 16 33
5
P.P.C.
IS 1489 - 1991 300 10 30 600 16 22 33
6
Low Heat
IS 12600 - 1989 320 10 60 600 10 16 35
7
High Alumina
IS 6452 - 1989 225 5 30 600 10 16 33
8
Super Sulphated
IS 6909 - 1990 400 5 30 600 15 22 30
9
Slag Cement
IS 445 - 1989 225 5 30 600 16 22 33
10
Masonry Cement
IS 3466 - 1988 N.S. 10 90 1440 N.S. 2.5 5