This document provides information on concrete technology, specifically focusing on cement. It discusses the key ingredients in cement including lime, silica, alumina, iron oxide, and calcium sulfate. It explains the chemical compounds that form when water is added to cement, called Bogue compounds, and their roles in strength development over time. The document also covers testing methods for cement, including consistency testing to determine standard water content, setting time tests, compressive strength tests, and soundness tests to ensure cement does not excessively expand when setting.

1. CONCRETE TECHNOLOGY
CONTENTS
1.CEMENT ,AGGREGATE AND WATER
2. CONCRETE
3. CONCRETE MIX- DESIGN AND TESTING OF CONCRETE
4.QUALITY CONTROL OF CONCRETE
5. CHEMICAL ADMIXTURES, SPECIAL CONCRETE AND
EXTREME WEATHER CONCRETING

2. 1.CEMENT-
-It is used as the binding material only when it is contact
with water.

3. Composition of cement
i) Calcareous compound (Calcium)- lime, chalk,
marine shells, marble.
LIME MARINE SHELLS

4. ii) Argillaceous compound (Silica)- clay, shale,
slate, alumina, blast furnace slag.
CLAY SHALE

5. 2.CEMENT
Constituents of cement-
i)Lime (CaO):- 62-67%
ii)Silica(SiO2):-17-25%
iii)Alumina(Al2O3):-3-8%
iv)Calcium sulphate(CaSo4):-3-4%
v)Iron oxide (Fe2O3):- 3-4%
vi)Magnesia(MgO):- 1-3%
vii)Sulphur(S):1-3%
viii)Alkalies(K2O and Na2O):-0.2-1%

6.  Functions of Cement Ingredients
 The main features of these cement ingredients along with their
functions and usefulness or harmfulness are given below:
 Lime: Lime is calcium oxide or calcium hydroxide.
 The presence of lime in a sufficient quantity is required to form silicates
and aluminates of calcium.
 Deficiency in lime reduces the strength of property to the cement.
 Deficiency in lime causes the cement to set quickly.
 Excess lime makes cement unsound.
 The excessive presence of lime causes the cement to expand and
disintegrate.
 Silica: Silicon dioxide is known as silica, chemical formula SiO2.
 The sufficient quantity of silica should be present in cement to dicalcium
and tricalcium silicate.
 Silica imparts strength to cement.
 Silica usually presents to the extent of about 30 percent cement.

7.  Alumina: Alumina is Aluminium oxide. The chemical formula
is Al2O3.
 Alumina imparts quick setting property to the cement.
 Clinkering temperature is lowered by the presence of the requisite
quantity of alumina.
 Excess alumina weakens the cement.
 Magnesia: Magnesium Oxide. The chemical formula is
MgO.
 Magnesia should not be present more than 2% in cement.
 Excess magnesia will reduce the strength of the cement.

8.  Iron oxide: Chemical formula is Fe2O3.
 Iron oxide imparts color to cement.
 It acts as a flux.
 At a very high temperature, it imparts into the chemical reaction with
calcium and aluminum to form tricalcium alumino-ferrite.
 Tricalcium alumino-ferrite imparts hardness and strength to cement.
 Calcium Sulfate: Chemical formula is CaSO4
 This is present in cement in the form of gypsum(CaSO4.2H2O)
 It slows down or retards the setting action of cement.
 Sulphur : Chemical formula is S
 Excess Sulphur causes the cement to unsound, which leads to volume
changes.
 Alkaline:
 It should not be present more than 1%.
 Excess Alkaline matter causes efflorescence.

9.  Bogues Compounds: when water is added to cement it
react with the ingredients of the cement chemically &
results in the formation of complex
chemical compounds terms as BOGUES compounds.
1.Tri-Calcium Aluminate (3CaO.Al2O3 or C3A) - 8-12%
2. Tetra Calcium Alumino Ferrate (4CaO.Al2O3.Fe2O3 or
C4AF)- 6-10%
3. Tri-Calcium Silicate (3CaO.SiO2 or C3S)- 30-50%
4. Di-Calcium Silicate (2CaO.SiO2 or C2S) - 20-45%

10.  Tri-Calcium Aluminate (3CaO.Al2O3 or C3A)
 Formed in 24 hrs of addition of water
 Max. evolution of heat of hydration
 check setting time of cement
2. Tetra Calcium Alumino Ferrate (4CaO.Al2O3.Fe2O3 or
C4AF)
 Formed within 24 hrs of addition of water
 High heat of hydration in initial periods

11.  3. Tri-Calcium Silicate (3CaO.SiO2 or C3S)
 Formed within week
 Responsible for initial strength of cement
 Contribute about 50-60% of strength
 Content increase for the pre fabricated concrete
construction, Cold weathering construction.
 4. Di-Calcium Silicate (2CaO.SiO2 or C2S)
 Last compound formed during hydration of cement
 responsible for progressive later stage strength
 Structure requires later stages strength proportion of this
component increase
 e.g. hydraulic structures, bridges.

13.  Descending order of rate of hydration
C4AF>C3A>C3S>C2S
 Descending order of heat of hydration
C3A>C3S>C4AF>C2S
Heat of hydration (cal/gm)
compounds 3 days 90days
C3A 210 310
C4AF 70 100
C3S 60 105
C2S 10 40

14. -Heat of hydration of OPC at the age of 7 days is
approximately 89 to 90 cal/gm and at the age 28 days is in
the range of 90 to 100 cal/gm.
-C3S requires approximately 24% of water by weight for thr
complete hydration where C2S requires approximately 21%
of water by weight for its complete hydration.
-cement in total requires 23% water by weight for its complete
hydration.
-About 15% of the water is entrapped in the voids of the
cement particles. It is not available for hydration process.
Hence total water required for complete hydration of water is
approximately 38%.

15.  Water cement ratio
-The water–cement ratio is the ratio of the weight of water to
the weight of cement used in a concrete mix.
-A lower ratio leads to higher strength and durability, but may
make the mix difficult to work with and form. Workability can
be resolved with the use of plasticizers or super-plasticizers.
- Normally water cement ratio falls under 0.4 to 0.6 as per IS
Code 10262 (2009) for nominal mix (M10, M15 …. M25).

16.  Testing of cement
-Quality Tests on cement are carried out to check the strength
and quality of the cement used in construction. It helps to
identify the usage of cement for different purposes based on
its durability and performance.
-The following tests are conducted on cement in the
laboratory are as follows:
 Fineness Test
 Consistency Test
 Setting Time Test
 Strength Test
 Soundness Test
 Heat of Hydration Test
 Tensile Strength Test
 Chemical Composition Test

17.  Fineness of cement
-The fineness of cement is responsible for the rate of hydration, rate
of evolution of heat and the rate of gain of strength. Finer the
grains more is the surface area and faster the development of
strength.
-The fineness represents the particle size of cement. It should not be
greater than 90-microns when sieved as per IS standard.
-The fineness of cement can be determined by Sieve Test or Air
Permeability test.
 Sieve Test:
-In this test 100gm of sample to be tested is placed over IS Sieve no.
9(90 µ) and the cement is sieved continuously in a circular and
vertical motion for a period of 15 minutes. The residue left on the
sieve is weighed, and it should not exceed 10% for ordinary
cement. This test is rarely used for fineness.

18.  Air Permeability test
- Blaine's Air Permeability Test is used to find the specific
surface, which is expressed as the total surface area in
sq.cm/g. of cement. The surface area is more for finer
particles.
- For OPC, specific surface area should not be less than
2250 cm2/gm.

19.  consistency test apparatus, Vicat's apparatus.
- Standard consistency of cement paste is defined as that
water content which will permit a Vicat plunger of 10 mm
diameter and 50 mm length to penetrate depths of 33-35
mm within 3-5 minutes of mixing.
 The test has to undergo three times, each time the cement
is mixed with water varying from 24 to 27% of the weight of
cement.
 This test should be conducted at a constant temperature of
25°C or 29°C and at a constant humidity of 20%.

20.  Setting Time of cement
 Vicat's apparatus is used to find the setting times of cement
i.e., initial setting time and final setting time.
 Initial Setting Time:
- It is defined as the time that is measured from the instant,
water is added into the cement upto the time it start loosing
its plasticity.
- In order to perform this test,500gms of sample is taken and
gauged with 0.85p and the paste prepared is filled in the
mould.
- For this test, a needle of 1 mm square size is used. The
needle is allowed to penetrate into the paste (a mixture of
water and cement as per the consistency test). The time
taken to penetrate 33-35 mm depth is recorded as the initial
setting time.
- For OPC, initial setting time is approximately 30 min.

21.  Final Setting Time:
- It is defined as the time that is measured from the instant,
water is added into the cement upto the time it completely
loosing its plasticity and attain sufficient firmness, So as to
resist definite pressure.
- After the paste has attained hardness, the needle does not
penetrate the paste more than 0.5 mm. The time at which
the needle does not penetrate more than 0.5 mm is taken as
the final setting time.
- For OPC, Final setting time is approximately 10 hrs.

22.  Strength test of cement
 Compressive strength test
- The strength of cement cannot be defined directly on the
cement. Instead the strength of cement is indirectly defined
on cement-mortar of 1:3. The compressive strength of this
mortar is the strength of cement at a specific period.
- Water is added in the mortar in the proportion of [p/4+3]%
and the paste prepared is filled in the mould of size 150 mm
and compacted and immersed in the water for curing.
- Samples are further being tested for compressive strength in
CTM.

23.  Soundness test of cement
- No significant change in the volume of cement takes place
after its setting as it affects the durability of the structure in
which it is used for construction.
- Unsoundness of the cement is due to the presence of lime,
magnesia and sulphur in it.
- This test is conducted in Le Chatelier's apparatus to detect
the presence of uncombined lime and magnesia in cement.

24.  Unsoundness due to lime
- It is measured by Le Chatelier's apparatus , that consist of
split cylinder of dia and height of 30 mm and indicator arms
of length 165mm provided on either side of the split.
- Cement is gauged with 0.78 times then the required and
filled into the mould kept on the glass plate then it will
covered on the top with another glass plate.
- Immersed in water at room temperature and kept for
24hrs.
- Measure the distance between the indicator and again
immersed into the water, Heat the water for about 3 hrs
and then remove it and allow to cool.
- Measure the distance between the indicator points
- Split not more than 10 mm.

25.  Unsoundness due to Magnesia
- It is measured by Auto clave test.
- This test is sensitive to both Unsoundness due to line and
Magnesia .
- In this test the mould of size 25×25×282 mm from the given
sample of the lean cement and is placed in the apparatus.
- Steam pressure is increased such that gauges pressure of
21kg/cm2 is attain in 1hr and is maintain for next 3 hrs.
- The mould is removed from the apparatus allowed to pulled
of and is tested for its size.
- For OPC, increase in size of any side should not exceed
0.8%.

26.  PHYSICAL PROPERTIES OF OPC(ORDINARY
PORTLAND CEMENT)
PROPERTIES VALUES
Specific Gravity 3.12
Normal Consistency 29%
Initial Setting time 65min
Final Setting time 275 min
Fineness 330 kg/m2
Soundness 2.5mm
Bulk Density 830-1650 kg/m3

27.  PHYSICAL PROPERTIES OF PPC (POZZOLANA
PORTLAND CEMENT)
PROPERTIES VALUES
Fineness (by
Blaines apparatus)
Not less than 300 m2/Kg
Soundness
a) Le Chatelier
method
Not more than 10 mm
b) Autoclave test Not more than 0.8%
Setting time
a) Initial setting time
in minutes
Not less than 30
b) Final setting time
in minutes
Not less than 600

28. PROPERTIES VALUES
Compressive strength
a) (3 days) Not less than 16 MPa
b) (7 days) Not less than 22 MPa
c) (28 days) Not less than 33 MPa
5. Drying shrinkage % Not more than 0.15

29. -DIFFERENT GRADES OF OPC-
- As per Indian standard code there are three types of grade-
PHYSICAL PROPERTIES-
GRADES 33 43 53
Setting Time
3
days
7
Days
28
Days
3
days
7 Days
28
Days
3 days 7 Days
28
Days
Avg.
Compressiv
e Strength
in N/mm^2
16 22 33 23 33 43 27 37 53
Fineness in
m^2 /kg,
Min.
225
225 225

30. SOUNDNESS
a) By Le Chatelier method,
mm, Max
10
b) By autoclave test method,
percent, Max
0.8
Setting time
a) Initial in minutes, Min 30
b) Final in minutes, Max 600

31. STORAGE OF CEMENT AND EFFECT OF STORAGE ON
PROPERTIES OF CEMENT-
Precautions should be taken while storing of cement on site are as
following:
 1. Before the storage the cement ensure that the separate
industrial shade.
 2. Cement should be stored in a special water-tight shed with a dry
and damp proof door, waterproof walls and leak proof shade.
 3. Building should be with 150 mm concrete floor and 230 mm
brick walls.
 4. For ventilation there should be exhaust fans and Windows.
 5. Bags should be stored in such a way that received first should
be used first.
 6. The stacks of cement bag should be placed at a distance of at
least 30 cm from walls with 1 m gap between two rows for easy
handling.
 7. Bags should not be stacked more than 8 to 10 bags vertically.
 8.Width of stack should not exceed 3 m.

32. STORAGE OF CEMENT AND EFFECT OF STORAGE ON
PROPERTIES OF CEMENT-
 Effect of storage of cement on properties:
 1. Due to long storage of cement, cement loses its strength,
cement becomes lumpy and due to its loss of capacity for
hydration, becomes unusable.
 2. When a sealed bag of cement is opened, oxygen in air
starts reacting with the ingredients as well as the humidity in
the air starts reactions with the ingredients.
 3. It is advisable to use cement stored within 3 months at the
maximum.

33. Effect of storage of cement on properties:
 Cement fresh form factory – 100% strength
 Reduction In Strength
Cement Reduction In Strength
Fresh Nil
After 3 Months 15%
After 6 Months 25%
After 1 Year 40%
After 2 Years 52%

34. FIELD APPLICATION of DIFFERENT TYPES OF CEMENT :
1. RAPID HARDENING CEMENT-
- The Rapid Hardening Cement is used for repair and
rehabilitation works and where speed of construction and
early completion is required due to limitations of time,
space or other reasons.
- The cement is to be used in cold weather concreting i.e.
temperature < 5oC.
- Rapid hardening cement is basically OPC but its fineness is
3250 cm2/g against 2250 cm2/g in case of OPC.

35. -The compressive strength after 1 day is 16 N/mm2 and that of
3 days 27 N/mm2.
-These days higher grade OPC are available in the country to
meet these requirements and therefore, this cement is not
being manufactured and marketed on regular basis.
2. LOW HEAT CEMENT-
- Low Heat Portland Cement is particularly suited for making
concrete for dams and many other types of water retaining
structures, bridge abutments, massive retaining walls, piers
and slabs etc.
- - In mass concreting, there is often considerable rise in
temperature because of the heat produced as the cement
sets and hardens.

36. -The shrinkage which occurs on subsequent cooling sets up
tensile stresses in the concrete, may result in cracking.
-The use of low heat cement is advantageous since it evolves
less heat than OPC.
3. PORTLAND POZZOLANA CEMENT-
-Portland pozzolana cement is prepared by grinding pozzolanic
clinker with Portland cement.
-It is also produced by adding pozzolana with the addition of
gypsum or calcium sulfate or by intimately and uniformly
blending Portland cement and fine pozzolana.

37. -This cement has a high resistance to various chemical attacks
on concrete compared with ordinary portland cement, and
thus, it is widely used.
-It is used in marine structures, sewage works, sewage works,
and for laying concrete underwater, such as bridges, piers,
dams, and mass concrete works, etc
4. SULPHATE RESISTING CEMENT-
- Sulfate resisting cement is used to reduce the risk of sulfate
attack on concrete and thus is used in the construction of
foundations where the soil has high sulfate content.

38.  Sulfate resisting cement is used in construction exposed to
severe sulfate action by water and soil in places like canals
linings, culverts, retaining walls, siphons, etc.
 5. BLAST FURNACE SLAG-
 Slag from a blast furnace is actually a waste product.
 Application
 Blast furnace slag cement mainly used in Marine
construction.
 It is used in Mass concreting.
 Also used for sea walls and break waters.
 All construction work when OPC is used.

39.  Sulfate resisting cement is used in construction exposed to
severe sulfate action by water and soil in places like canals
linings, culverts, retaining walls, siphons, etc.
 6. HIGH ALUMINA CEMENT-
 High alumina cement is obtained by melting a mixture of
bauxite and lime and grinding with the clinker. It is a rapid
hardening cement with initial and final setting time of about
3.5 and 5 hours, respectively.
 The compressive strength of this cement is very high and
more workable than ordinary portland cement and is used in
works where concrete is subjected to high temperatures,
frost, and acidic action.

40.  7. WHITE CEMENT-
 White cement is used in decoration works like false ceiling.
 It is used in high class filing works so that the joints are not
visible.
 Also its used for internal plaster work and finishing work.
 White cement is also used for waterproofing work.