Building Materials.pptx

Types of cement with their specific use
Grades of cement as per BIS
Engineering properties of cement
Field and Laboratory test of cement as per
BIS
Methods of storing the cement

 The invention of Portland cement usually is attributed to Joseph
Aspdin of Leeds, Yorkshire, England, who in 1824 took out a patent for a material that
was produced from a synthetic mixture of limestone and clay.
 He called the product “Portland cement” because of a fancied resemblance of the
material, when set, to Portland stone, a limestone used for building in England.
Aspdin’s product may well have been too lightly burned to be a true Portland cement,
and the real prototype was perhaps that produced by Isaac Charles Johnson in
southeastern England about 1850. The manufacture of Portland cement rapidly
spread to other European countries and North America.
 During the 20th century, cement manufacture spread worldwide. By 2019 China and
India had become the world leaders in cement production, followed by Vietnam, the
United States, and Egypt.

 Portland cement consists essentially of compounds of lime.
 (calcium oxide, Cao) mixed with silica (silicon dioxide, SiO2) and
 Alumina (aluminum oxide, Al2O3). The lime is obtained from a calcareous (lime-
containing) raw material, and the other oxides are derived from an argillaceous
(clayey) material.
 Additional raw materials such as silica sand, iron oxide (Fe2O3), and bauxite—
containing hydrated aluminum, Al(OH)3—may be used in smaller quantities to get the
desired composition.

 Cement is one of the most important building materials, is a binding agent that sets
and hardens to adhere to building units such as stones, bricks, tiles, etc. Cement
generally refers to a very fine powdery substance.
 The raw ingredients are processed in cement manufacturing plants and heated to
form a rock-hard substance, which is then ground into a fine powder to be sold.
 Cement mixed with water causes a chemical reaction and forms a paste that sets and
hardens to bind individual structures of building materials.
 Cement is an integral part of the urban infrastructure. It is used to make concrete as
well as mortar, and to secure the infrastructure by binding the building blocks.
 Concrete is made of cement, water, sand, and gravel mixed in definite proportions,
whereas mortar consists of cement, water, and lime aggregate.

Ingredients Normal range in % Typical Composition %
1)Lime (Cao) 60-70% 62
2)Silica (SiO2) 17-25% 22
3)Alumina (Al2O3) 3-8% 5
4)Iron Oxide (Fe2O3) 0.5 – 6% 3
5)Magnesia (MgO) 0.1-4% 2
6)Sulphur Trioxide (SO3) 1-3% 1
7)Soda or potash 0.5 – 1.3% 1
8)Calcium sulphate (CaSo4) 3 – 5% 4
Total 100

1. Ordinary Portland Cement (OPC)
2. Portland Pozzolana Cement (PPC)
3. Rapid Hardening Cement
4. Quick setting cement
5. Low Heat Cement
6. Sulphates resisting cement
7. Blast Furnace Slag Cement
8. High Alumina Cement
9. White Cement
10.Coloured cement
11.Air Entraining Cement
12.Expansive cement
13.Hydrophobic cement

 OPC is the most widely used type of cement, which is suitable for all general concrete
construction.
 It is the most commonly produced and used type of cement around the world, with
annual global production of around 3.8 million cubic meters per year.
 This cement is suitable for all kinds of concrete construction.

 PPC is prepared by grinding pozzolanic clinker with Portland cement.
 It is also produced by adding pozzolana with the addition of gypsum or calcium
sulphate or by intimately and uniformly blending Portland cement and fine pozzolana.
 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.

 Rapid hardening cement attains high strength in the early days; it is used in concrete
where formworks are removed at an early stage and are similar to ordinary Portland
cement (OPC).
 This cement has increased lime content and contains higher c3s content and finer
grinding, which gives higher strength development than OPC at an early stage.
 The strength of rapid hardening cement at the three days is similar to 7 days strength
of OPC with the same water-cement ratio.
 Thus, the advantage of this cement is that formwork can be removed earlier, which
increases the rate of construction and decreases the cost of construction by saving
formwork cost.
 Rapid hardening cement is used in prefabricated concrete construction, road works,
etc.

 The difference between the quick setting cement and rapid hardening cement is that
quick-setting cement sets earlier.
 At the same time, the rate of gain of strength is similar to Ordinary Portland Cement,
while quick hardening cement gains strength quickly.
 Formworks in both cases can be removed earlier.
 Quick setting cement is used where works is to be completed in very short period and
for concreting in static or running water.

 Low heat cement is produced by maintaining the percentage of tricalcium aluminate
below 6% by increasing the proportion of C2S.
 A small quantity of tricalcium aluminate makes the concrete to produce low heat of
hydration.
 Low heat cement suitable for mass concrete construction like gravity dams, as the low
heat of hydration, prevents the cracking of concrete due to heat.
 This cement has increased power against sulphates and is less reactive and initial
setting time is greater than OPC.

 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.
 This cement has reduced the contents of C3A and C4AF.
 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.

 Blast furnace slag cement is obtained by grinding the clinkers with about 60% slag
and resembles more or less in properties of Portland cement.
 It can be used for works where economic considerations are predominant.

 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.

 It is prepared from raw materials free from Iron oxide and is a type of ordinary
Portland cement, which is white.
 It is costlier and is used for architectural purposes such as precast curtain wall and
facing panels, terrazzo surface, etc. and for interior and exterior decorative work like
external renderings of buildings, facing slabs, floorings, ornamental concrete products,
paths of gardens, swimming pools, etc.

 It is produced by mixing 5- 10% mineral pigments with ordinary cement.
 They are widely used for decorative works on floors.

 Air entraining cement is produced by adding indigenous air-entraining agents such as
resins, glues, sodium salts of sulfates, etc. during the grinding of clinker.
 This type of cement is especially suited to improve the workability with a smaller
water-cement ratio and to improve frost resistance of concrete.

 Expansive cement expands slightly with time and does not shrink during and after the
time of hardening.
 This cement is mainly used for grouting anchor bolts and prestressed concrete ducts.

 Hydrophobic cement is prepared by mixing water-repelling chemicals and has high
workability and strength.
 It has the property of repelling water and is unaffected during monsoon or rains.
 Hydrophobic cement is mainly used for the construction of water structures such as
dams, water tanks, spillways, water retaining structures, etc.

 There are different grades of cement, Grade of Cement is nothing but the strength of
cement (How much strength a person has to lift a weight, is same related to the How much
Strength does cement can yield or bear.)
 The grade is the metric to measure the strength of cement. There are different grades of
of cement increases as the grade of cement increases. Fineness of cement increases with
grade. Grade of cement is chosen as per the one requirement and type of work.
 Different grades of cement
No matter what's the brand of cement is, There are three different grades of Ordinary
available in the market.
1.33 Grade
2.43 Grade
3.53 Grade

 As per Indian Standards, IS 269 – 2015, 33 Grade of cement means the Compressive Strength
of cement after 28 days is 33 N/mm2. This grade of cement is outdated and no one is using in
recent times. 33 Grade of cement is not suitable for making more than M20 grade of concrete.
 Where to use 33 grade of cement?
This type of cement is generally used for building compound walls, parapet walls, etc.

 As you already know 43 grade of cement means the Compressive strength of cement when tested under
the CTM is 43N/mm2 as per Indian Standards, IS 8112 – 2013. Concrete of grade up to M30 grade can
be made using 43 grade of cement.
This type of cement is used in making Plain Cement Concrete (PCC) and for plastering the walls, brickwork
mortar, Precast items like tiles, Cement pipes.

 This is the high grade of cement where anyone can easily buy from the market. The Strength of cement
having the Compressive strength of 53N/mm2 is called 53 grade of cement as per Indian standards IS
12269-2013. The setting time of cement is quicker when compared with the 33 and 43 grade of cement.
Any grade more than M25 is easily achievable by using 53 grade of cement.
This type of cement is used in Precast walls, Concrete Roads, Bridges, Dams, RCC for Structural works.

 Different blends of cement used in construction are characterized by their physical
properties. Some key parameters control the quality of cement. The physical properties of
good cement are based on:
1) Fineness of cement
2) Soundness
3) Consistency
4) Strength
5) Setting time
6) Heat of hydration
7) Loss of ignition
8) Bulk density
9) Specific gravity (Relative density)

 The size of the particles of the cement is its fineness.
 The required fineness of good cement is achieved through grinding the clinker
in the last step of cement production process.
 As hydration rate of cement is directly related to the cement particle size,
fineness of cement is very important.

 Soundness refers to the ability of cement to not shrink upon hardening.
 Good quality cement retains its volume after setting without delayed
expansion, which is caused by excessive free lime and magnesia.

 The ability of cement paste to flow is consistency.
 It is measured by Vicat Test.
 In Vicat Test Cement paste of normal consistency is taken in the Vicat
Apparatus. The plunger of the apparatus is brought down to touch the top
surface of the cement. The plunger will penetrate the cement up to a certain
depth depending on the consistency. A cement is said to have a normal
consistency when the plunger penetrates 10¡À1 mm.

 Three types of strength of cement are measured compressive, tensile and
flexural. Various factors affect the strength such as water-cement ratio, cement-
fine aggregate ratio, curing conditions, size and shape of a specimen, the
manner of molding and mixing, loading conditions and age.
 Compressive Strength: It is the most common strength test. A test specimen
(50mm) is taken and subjected to a compressive load until failure. The loading
sequence must be within 20 seconds and 80 seconds.
 Tensile strength: Though this test used to be common during the early years of
cement production, now it does not offer any useful information about the
properties of cement.
 Flexural strength: This is actually a measure of tensile strength in bending. The
test is performed in a 40 x40 x 160 mm cement mortar beam, which is loaded
at its center point until failure.

 cement sets and hardens when water is added. This setting time can vary
depending on multiple factors, such as fineness of cement, cement-water ratio,
chemical content, and admixtures.
 Cement used in construction should have an initial setting time that is not too
low and a final setting time not too high. Hence, two setting times are
measured:
 Initial set: When the paste begins to stiffen noticeably (typically occurs within
30-45 minutes)
 Final set: When the cement hardens, being able to sustain some load (occurs
below 10 hours)

 When water is added to cement, the
reaction that takes place is called
hydration.
 Hydration generates heat, which can
affect the quality of the cement and also
be beneficial in maintaining curing
temperature during cold weather.
 On the other hand, when heat generation
is high, especially in large structures, it
may cause undesired stress.
 The heat of hydration is affected most by
C3S and C3A present in cement, and also
by water-cement ratio, fineness and
curing temperature.
 The heat of hydration of Portland cement
is calculated by determining the
difference between the dry and the
partially hydrated cement (obtained by
comparing these at 7th and 28th days).

 When cement is mixed with water, the water replaces areas where there would
normally be air.
 Because of that, the bulk density of cement is not very important.
 Cement has a varying range of density depending on the cement composition
percentage. The density of cement may be anywhere from 62 to 78 pounds per
cubic foot.

 Specific gravity is generally used in mixture proportioning calculations.
 Portland cement has a specific gravity of 3.15, but other types of cement (for
example, Portland-blast-furnace-slag and Portland-pozzolan cement) may have
specific gravities of about 2.90.

 The raw materials for cement production are limestone (calcium), sand or clay
(silicon), bauxite (aluminum) and iron ore, and may include shells, chalk, marl, shale,
clay, blast furnace slag, slate.
 Chemical analysis of cement raw materials provides insight into the chemical
properties of cement.
Tricalcium aluminate (C3A)
 Low content of C3A makes the cement sulphate-resistant.
 Gypsum reduces the hydration of C3A, which liberates a lot of heat in the early stages
of hydration.
 C3A does not provide any more than a little amount of strength.
Type I cement: contains up to 3.5% SO3 (in cement having more than 8% C3A)
Type II cement: contains up to 3% SO3 (in cement having less than 8% C3A)

Tricalcium silicate (C3S)
C3S causes rapid hydration as well as hardening and is responsible for the cement’s
early strength gain an initial setting.
Dicalcium silicate (C2S)
As opposed to tricalcium silicate, which helps early strength gain, dicalcium silicate in
cement helps the strength gain after one week.
Ferrite (C4AF)
Ferrite is a fluxing agent. It reduces the melting temperature of the raw materials in the
kiln from 3,000°F to 2,600°F. Though it hydrates rapidly, it does not contribute much to
the strength of the cement.

Magnesia (MgO)
The manufacturing process of Portland cement uses magnesia as a raw material in
dry process plants. An excess amount of magnesia may make the cement unsound
and expansive, but a little amount of it can add strength to the cement. Production of
MgO-based cement also causes less CO2 emission. All cement is limited to a content
of 6% MgO.
Sulphur trioxide
Sulfur trioxide in excess amount can make cement unsound.
Iron oxide/ Ferric oxide
Aside from adding strength and hardness, iron oxide or ferric oxide is mainly
responsible for the color of the cement.

Alkalis
The amounts of potassium oxide (K2O) and sodium oxide (Na2O) determine the alkali
content of the cement. Cement containing large amounts of alkali can cause some
difficulty in regulating the setting time of cement.
Low alkali cement, when used with calcium chloride in concrete, can cause
discoloration. In slag-lime cement, ground granulated blast furnace slag is not
hydraulic on its own but is "activated" by addition of alkalis.
There is an optional limit in total alkali content of 0.60%, calculated by the equation
Na2O + 0.658 K2O.
Free lime
Free lime, which is sometimes present in cement, may cause expansion.

Silica fumes
Silica fume is added to cement concrete in order to improve a variety of properties,
especially compressive strength, abrasion resistance and bond strength. Though
setting time is prolonged by the addition of silica fume, it can grant exceptionally high
strength. Hence, Portland cement containing 5-20% silica fume is usually produced for
Portland cement projects that require high strength.
Alumina
Cement containing high alumina has the ability to withstand frigid temperatures since
alumina is chemical-resistant. It also quickens the setting but weakens the cement.

 Sometimes it may be required to perform cement quality tests at a site within a very
short period of time for evaluating the condition of the supplied cement.
 In most of the cases, it is not possible to have any laboratory test in the short period of
time.
 Therefore, the quality check is performed with the help of some basic field tests.
Although these tests are not very accurate, they provide some basic idea to the civil
engineer regarding the quality of the cement.

1. Date of Manufacturing: As the strength of cement reduces with age, the date
of manufacturing of cement bags should be checked.
2. Cement Color: The color of cement should be uniform. It should be typical cement
color i.e. gray color with a light greenish shade.
3. Whether Hard Lumps are Formed: Cement should be free from hard lumps. Such
lumps are formed by the absorption of moisture from the atmosphere.
4. Temperature Inside Cement Bag: If the hand is plunged into a bag of cement, it
should be cool inside the cement bag. If hydration reaction takes place inside the bag, it
will become warm.

5. Smoothness Test: When cement is touched or rubbed in between fingers, it should
give a smooth feeling. If it felt rough, it indicates adulteration with sand.
6. Water Sinking Test: If a small quantity of cement is thrown into the water, it should
float some time before finally sinking.
7. The smell of Cement Paste: A thin paste of cement with water should feel sticky
between the fingers.
If the cement contains too much-pounded clay and silt as an adulterant, the paste will
give an earthy smell.

8. Glass Plate Test: A thick paste of cement with water is made on a piece of a glass
plate and it is kept under water for 24 hours. It should set and not crack.
9. Block Test: A 25mm × 25mm × 200mm (1”×1”×8”) block of cement with water is
made. The block is then immersed in water for three days. After removing, it is
supported 150mm apart and a weight of 15kg uniformly placed over it. If it shows no
sign of failure the cement is good.
 https://www.youtube.com/watch?v=f_YnylDTpo4

 Cement Tests are performed to know the strength and characteristic
properties of cement. Various Test on cement is known nowadays to
check the quality of cement.
 To know the properties of cement such as specific gravity, strength,
fineness, consistency, etc. various Cement Testing Methods are used.
Testing of materials is essential before use in construction work.

 The following tests on cement in the laboratory,
1.Fineness test of Cement
2.Consistency test of Cement
3.Setting time test of Cement
4.Soundness test of Cement
5.Heat of hydration of Cement
6.Specific gravity test of Cement
7.Tensile strength test
8.Chemical composition test

 The fineness of cement is a
measure of cement particle size
and is denoted as terms of the
specific surface area
of cement. The Test is done by
sieving cement sample
through standard IS sieve.
 The weight cement particle whose
size greater than 90 microns is
determined and the percentage of
the retained particle are
calculated. This is known as
the Fineness of cement.

Apparatus required
 90 microns IS Sieve
 Weighing balance having a capacity
of 10 mg to 100 g
 Nylon or pure bristle brush
IS Code
Determining the fineness of cement by
using 90 microns IS Sieve is done as
per IS 4031 (part 1) – 1996.
RESULT
The standard value of finess of cement
should have fineness less than 10 % or
fineness should not be more than 10 %
as per IS recommendations.

 The standard consistency of cement
past is defined as the percentage of
water added in 300 gm weight of
cement which will permit a vicat
plunger having 50 mm length and 10
mm diameter to penetrate in cement
paste to a depth of 33-35 mm from
the top of the mould.

 Vicat apparatus
 Weighing Balance
 Gauging Trowel
 Stop watch, etc.
IS Code
Consistency test of cement IS codes –
IS:5513-1976, IS:4031 (part 4) - 1988
 RESULT
The standard consistency of cement
paste generally varies between 25-
35%.

 Initial setting time gives an idea about
how fast cement can start losing
its plasticity and the final setting
time of cement gives an idea about
how much Time cement takes to lose
its full plasticity and gain some strength
to resist pressure.
 Initial Setting Time of Cement: It is
the time elapsed between the moments
that the water is added to the cement,
to the time that the paste starts losing
its plasticity.
 Final Setting Time of Cement: It is
the time elapsed between the moment
the water is added to the cement and
the time when cement paste loses its
plasticity completely and has attained
sufficient firmness to resist certain
definite pressure.

 Weighing balance
 Vicat apparatus
 Stop watch
 Gauging or mixing trowel
 Glass plate
 Enamel tray
IS Code
As per IS:4031 (part 5) – 1988. The
initial and final setting time of cement is
calculated using the VICAT apparatus
conforming to IS: 5513 -1976.
RESULT
As per standards, the initial setting time
of cement should be less than 30 min for
OPC cement. Whereas, it should not be
more than 600 min for OPC cement.

 The soundness of cement indicates
the stability of any cement during
the volume change in the process of
setting and hardening.
 In case the volume change in cement
is unstable after setting and
hardening, the concrete element will
crack, which can affect the quality of
the structure or even cause serious
accidents, known as poor
dimensional stability.

 Le-Chatelier mould
 Cement
 Glass sheets
 Mixing pan
 Trowel
 Weight
IS Code
IS code for soundness test of cement is
IS:4031-part-3-1988
RESULT
The soundness calculated L1-L2 for
the types of cement ordinary or OPC,
rapid, low heat, PPC, and high
alumina cement should not exceeds 10
mm

 During the curing of concrete, hydro-
thermal reaction takes place,
resulting in the production of heat
because of chemical reactions. The
rise of heat in concrete could be as
high as 50 degrees.
 Hence in order to reduce such heat,
low heat cement is used. The test is
carried out using a calorimeter using
the principle of heat gain.

 Calorimeter
 Insulated wood case
 Thermometer plus holder
 Vacuum jar with stopper
 Glass funnel
 Stirring paddle and chuck
IS Code
IS:4031-1968 is recommended for
testing the heat of hydration of
cement.
RESULT
It has been standardised that the low
heat cement should not generate the
heat of 65 calories per gram of cement
in 7 days and 75 calories per gram for
the duration of 28 days.

 The specific gravity of cement is
defined as the mass of cement of
specified volume to the mass of
water of the same volume of cement.
 It can also be defined as the density
of cement to the density of water for
the same volume.

 Le chaterlier’s flask
 Weighing balance
 Kerosene (free from water)
IS Code
IS code for specific gravity test is
IS 2270-Part 3
RESULT
The specific gravity of cement is 3.1 to
3.16 g/cc. Around this value, the
specific gravity of cement is considered
to be standard and suitable for
construction.
NOTE:
From this, we can say that the specific
gravity of cement is more than the
specific gravity of water that is 1. It
means cement will sink in water if we
put it on the water. Also, we can say that
cement is heavier than water.

 The tensile strength of cement is the
maximum load that cement in its
hardened state can withstand
without fracture when tension is
applied.
 It is necessary to test the tensile
strength of cement or concrete
because concrete structures are
highly prone to tensile cracking due
to various kinds of load applied. As
compares to compressive strength is
very low.

Testing machine
 Tamping rod
 Concrete mould
 Trowel
IS Code
IS:456-2000 gives the formula for
calculating the tensile strength of
concrete.
 RESULT
The tensile strength of cement is
between 3-5 Mpa i.e., 300 – 700 psi.

 The components present in cement
for forming cement as the complete
products are lime or limestone,
silica, alumina, magnesia etc. Among
which most important of the raw
materials required for making
cement are limestone, clay, and marl.

 Flame Photometer and ELE Flame
Photometer are the instruments
used to know the constitutes of
cement.
IS Code
IS 269-1998 is recommended for
keeping a check on the chemical
composition of cement.
RESULT
A good cement should have the
constitution of components as per
listed,
 Lime or Limestone – 62%
 Silica – 22%
 Alumina – 7.5%
 Magnesia – 2.5%
 Other components – remaining 6%

 Wherever possible, the cement should be stored in weatherproof shed and kept dry.
 The shed should preferably be without any openings such as windows.
 The doors of such storages shed should be on leeward side to prevent rain
penetration and draughts.
 The floor for cement storage should be made of strong boards and joists raised clear
to the grounds, or of blanks load on a dry concrete slab above ground level.
 All cement should be stored for the shortest possible time.

 STORING OF CEMENT ON SITE – GUIDELINES
• Store cement in a building which is dry, leak proof and as moisture proof as possible.
• There should be minimum number of windows in the storage building.
• Stack the cement bags off the floor on wooden planks in such a way, so that it is about
150 mm to 200 mm above the floor.
• The floor may comprise of lean cement concrete or two layers of dry bricks laid on well
consolidated earth.
• Maintain a space of 600 mm all-round between the exterior walls and the stacks.(see
figure below)
• tack the cement bags close to each other to reduce circulation of air.
• The height of stack should not be more than 10 bags to prevent the possibility of lumping
under pressure.

• The width of the stack should not be more than four bags length or 3 meters.
• In stacks more than 8 bags high, the cement bags should be arranged alternately
length-wise and cross-wise, so as to tie the stacks together and minimize the danger
of toppling over.
• Stack the cement bags in such a manner so as to facilitate their removal and use in
the order in which they are received.
• Put label showing date of receipt of cement on each stack of cement bags to know
the age of cement.
• When it is required to store cement for a long period of time or during the monsoon;
completely enclose the stack by a water proofing membrane such as polyethylene.
• Different types of cement must be stacked and stored separately.

Sources and classification of Lime
Uses of lime with specific field situation
Types of pozzolanic materials
Advantages of addition of pozzolanic material

 The use of lime as a cementing material has been made since ancient times.
 The Egyptians and Romans made remarkable application of this material for various
constructional purposes.
 Even in India, the various engineering structures such as big palaces, bridges, temples,
forts, monuments, etc. were constructed with lime as a cementing material and some
of these structures still exist in perfectly good condition.
 At present, the cement has replaced lime to a great extent. But at places where lime is
locally available and when there is acute shortage of cement, the lime certainly
provides a cheap and a reliable alternative to the cement.

 The lime is not usually available in nature in free state.
 It is procured by- burning one of the following materials:
(i) Lime stones from the stone hills,
(ii) Boulders of lime stones from the beds of old rivers,
(iii) Kankar found below the ground, and
(iv) Shells of sea animals.
 It may be noted that white chalk is pure limestone and kankar is an impure limestone.

 Calcination: The heating of limestone to redness in contact with air is known as
calcination.
 Hydraulicity: It is the property of lime by which it sets or hardens in damp places,
water or thick masonry walls where there is no free circulation of air.
 Lime: Due to calcination of limestone, the moisture and carbon dioxide are
removed from it. The product which remains thereafter is known as the lime.
 It chemical composition is (Cao) i.e. oxide of calcium. The chemical reaction is as
follows
CaCO3 ------------- CaO + CO2

 Quick Lime: The lime which is obtained by the calcination of comparatively pure
limestone is known as the quick lime or caustic lime. It is capable of slaking with
water and has no affinity for carbonic acid.
 Its chemical composition of Cao i.e. oxide of calcium and it has great affinity for
moisture.
 Setting: The process of hardening of lime after it has been converted into paste
form is known as the setting. It is quite different from mere drying.
 Slaked Lime: The product obtained by slaking of quick lime is known as the
slaked lime or hydrate of lime. It is in the form of white powder and its chemical
composition is Ca(OH)2 or hydrated oxide of calcium.
CaO + H2O ---------- Ca(OH)2 + Heat

The limes which are obtained by calcination of lime stones are
broadly classified into the following three categories:
(1) Fat lime
(2) Hydraulic lime
(3) Poor lime.

 This lime is also known as the high calcium lime, pure lime, rich lime or white lime.
 It is popularly known as the fat lime as it slakes vigorously and its volume is increased
to about 2 to 2½ times the volume that of quick lime.
 It is prepared by calcining comparatively pure carbonate of lime which is composed of
about 95 per cent of calcium oxide.
 The percentage of impurities in such limestone is less than 5 per cent.

(i) It hardens very slowly.
(ii) It has a high degree of plasticity.
(iii) It is soluble in water which is changed frequently.
(iv) Its colour is perfectly white.
(v) It sets slowly in presence of air.
(vi) It slakes vigorously.

(i) It is used in whitewashing and plastering walls.
(ii) With sand, it forms lime mortar which sets in thin joints. Such mortar can be used
for thin joints of brickwork and stonework,
(iii) With surkhi, it forms lime mortar which possesses good setting and hydraulic
properties. Such mortar can be used for thick masonry walls, foundations, etc.
(iv) The surkhi is the powder obtained by grinding of the burnt bricks.

 This lime is also known as the water lime as it sets under water. It contains clay and some
amount of ferrous oxide.
 Depending upon the percentage of clay, the hydraulic lime is divided into the following
three types:
(i) Feebly hydraulic lime
(ii) Moderately hydraulic lime
(iii) Eminently hydraulic lime.
 Following facts should be noted:
(i) The increase in percentage of clay makes the slaking difficult and increases the hydraulic
property.
(ii) With about 30 per cent of clay, the hydraulic lime resembles natural cement.
(iii) The hydraulic lime can set under water and in thick walls where there is no free
circulation of air.

 This lime is also known as the impure lime or lean lime.
 It contains more than 30 per cent of clay.
 It slakes very slowly.
 It forms a thin paste with water.
 It does not dissolve in water though it is frequently changed.
 It sets or hardens very slowly.
 It has poor binding properties and its colour is muddy white.
 This lime makes a very poor mortar.
 Such mortar can be used for inferior type of work or at places where good lime is not
available.

The lime is an important engineering material and its uses can be
enumerated as follows:
(i) It is used as chemical raw material in the purification of water and for sewage
treatment.
(ii) It is used as a flux in the metallurgical industry.
(iii) It is used as a matrix for concrete and mortar.
(iv) It is used as a refractory material for lining open-hearth furnaces.
(v) It is used in the production of glass.

(vi) It is used for making mortar for masonry work.
(vii) It is used for plastering of walls and ceilings.
(viii) It is used for the production of artificial stone, lime-sand brick, foam- silicate
products, etc.
(ix) It is used for the soil stabilization and for improving soil for agricultural purposes.
(x) It is used for whitewashing and for serving as a base coat for distemper.
(xi) When it is mixed with Portland cement, the mortar attains valuable properties and
such a mortar can be used in place of the costly cement mortar.

 Depending upon the particle size,
chemical composition and dosage,
different pozzolans will affect the concrete
strength differently and at different times
during curing.
Typical pozzolans include:
• metakaolin
• silica fume
• fly ash
• slag
• VCAS (vitrified calcium alumino-silicate)

Left to right: Class C fly ash, Metakaolin,
Silica Fume, Class F fly ash, Slag, Calcined
Shale. From the Portland Cement Association

 Many pozzolans are waste products from industrial processes. As such the
color, quality, gradation and properties can vary and are not controlled.
• Fly ash comes from coal-fired power plants.
• Silica fume and slag come from some steel refineries.
 VCAS and metakaolin are purposefully manufactured pozzolans. Quality, color
and other characteristics can be controlled, so product consistency is greater.
There may also be different grades available.
• I recommend VCAS by Vitro Minerals because it is white, recycled and
enhances workability.

 The ideal dosage of VCAS is:
• For precast mixes, 15% cement replacement
• For GFRC mixes, 20% cement replacement
 The dosage range of pozzolans depends upon the particular pozzolan selected:

Pozzolan Dosage Effects
Fly ash: Class C 15% to 40% Increased workability. Early strength suffers with
higher replacement doses
Fly ash: Class F 15% to 25% Increased workability. Early strength suffers with
Slag 25% to 50% Increased workability. Early strength suffers with
Silica fume 5% to 10% Significantly decreased workability
VCAS 5% to 25 % Increased workability
Metakaolin 10% to 15% Decreased workability

Types of timber
Uses and application of timber
Defects in timber and wood
Seasoning
Wood products with specific uses

 The word timber is derived from an old English word Timberian which means to
build. Three terms are to be noted in connection with the timber:
1. Converted timber: This indicates timber which is sawn and cut into suitable
commercial sizes.
2. Rough timber: This indicates timber contained in a living tree.
3. Standing timber: This indicates timber contained in a living tree.
A timber is nothing but a form of wood that is shaped into beams and planks. It is
also known as “lumber” in the US and Canada.

 A single tree can cool the summer heat for an entire day and night and is found
better than 20 air-conditioners running for 20 hours.
 A hectare of trees will produce about 10 tons of oxygen which is enough for 45
person to live for one year.

 The structure of wood apparent only at great magnifications is called the
microstructure.
 Wood consists of living and dead cells of various sizes and shapes.
 A living cell consists of four parts, namely (i) membrane (ii) protoplasm (iii) sap
(iv)core.
 Cell membrane consists mainly of cellular tissue and cellulose. Protoplasm is a
granular, transparent, viscous, vegetables protein composed of carbon, hydrogen,
oxygen, nitrogen and Sulphur.
 Core of cell differs from protoplasm merely by the presence phosphorus and it is
generally oval.

 Different types of timbers are used for building construction as structural
members. Those woods which are adapted for building purposes are timbers.
Woods are cut and shaped in a specified dimension or standard size for the
industry.
1. Bamboo Timber
2. Birch Timber
3. Cedar Timber
4. Cherry Timber
5. Mahogany Timber
6. Oak Timber
7. Walnut
8. Fir Timber

 A bamboo tree is a natural organic tree
that is used for house construction. It
is one special and unique type of tree
on earth. Bamboo trees are available
in many countries, especially in
tropical and subtropical regions.
 Most of the timer-producing
bamboo trees are available in
South Asia. The Bamboo color
varies from pale yellow to almost
gold. It is one of the industrial
materials also identified as the
most promising building material.
 Bamboo timber is proven as an
alternative to tropical hardwoods in
recent years. It is available in any
size and length as per requirement.

 Birch is one of superior craft-
wood. It is a major source for
getting hardwood. Birch is
available in many forms like
yellow birch, white birch, etc.
Among these, the yellow birch is
widely used and is also known as
gray birch or swamp birch. Birch
offers a low natural luster.

 Cedar is one of the high-
quality types of wood. It is
manufactured from different trees
wood known as cedars.
 As when the strength and
appearance of the exposed wood
beams are essential requirements,
cedar is the only savior and perfect
fit for this.
 It is widely used for landscape,
park, and garden structures. It
offers moderate strength and
softness which makes it unique and
most important it is an easily
workable construction material.

 Cherry timber is well known as a tree
plantation type of wood. There are
many forms of cherry timber; but, black
cherry timber is a major source of
native cherries and the only of
commercial value.
 It is mostly found in Eastern United
Nations. The prime quality of cherry
timber is that its grains are generally
straight.
 It is one of the source of hardwood.
Cherry timber generally offers medium
density and is moderately durable.
 It is mostly used for small pieces of
furniture’s-veneers, handles, cabinets,
scientific instruments, etc.

 It has high quality as types of wood.
 It is utilized commercially in almost
every continent.
 Mahogany is majorly used for the
furniture and cabinet building industry.
 It is used to form plywood's and all
kinds of trim. It has hard grain.
 It is one of the softer wood among the
hardwoods that are commonly in use.
 Mahogany is a moderate natural luster.
Its color get darkens with age and the
texture is medium and uniform.
 The price of mahogany timber comes in
the medium range.

 Oak timber is processed from Oak
trees.
 One of the oldest timber used for
construction from the last
thousands of years.
 Oak types of wood has straight
gain.
 It is mostly used for light
construction work where no
heavy loads to be carry by timber.
 It is generally used for
homeware, wine barrels,
firewood, etc.

 It is one of the premium timber.
 It is the most popular and specialist
timber for house construction.
 It has a straight grain, but it can be
irregular.
 Walnut timber is widely used for
decorative purposes.
 It is available in a variety of designs
for the interior.
 It comes with a moderate natural
luster and is moderately durable.
 It has medium density.

 Fir is one of the most popular and
widely used timber species.
 It has major use and premium
product for a wide range of
applications.
 Fir is a softwood species and it
has a very straight grain.
 Fir becomes one of the standard
timber species for timber farming.
 It generally used for tin-housing,
framing, flooring, lining fascia's,
bargeboards, and pergolas.

Timber is used for the following works:
1. For heavy construction works like columns, trusses, piles.
2. For light construction works like doors, windows, flooring and roofing.
3. For other permanent works like for railway sleepers, fencing poles, electric poles and
gates.
4. For temporary works in construction like scaffolding, centering, shoring and strutting,
packing of materials.
5. For decorative works like showcases and furniture's.
6. For body works of buses, lorries, trains and boats
7. For industrial uses like pulps (used in making papers), card boards, wall papers
8. For making sports goods and musical instruments.

 Timber as construction material
1. Timber is one of the most useful and important material for constructions.
Selecting timber is not an easy task, because timber has different types out
of which selecting the right material is an important key.
2. Timber is an expensive material to be incorporated in a building for different
purpose therefore it should necessarily be strong, tough and durable.
3. Timber doors or windows and etc. contribute a lot in the beautification and
overall look of interiors. Timber is used in doors, windows, cabinet,
cupboards, shelves, tables and railings etc.
4. Timber is also popularly used in the form of plywood & raw wood. Products
like ply blocks and ply boards.
5. Heavy patterned doors and windows are made of solid wood/Timber to
provide the strength, toughness and durability.

 Type of timber to be used for right purpose is important because if timber used
in construction is of low quality then this may need replacement.
 While selecting timber one should consider its quality aspect as timber must be
free from decay like rotten, fungi and termite.
 Following are some essential tips and guidelines to know about timber
selection for buildings:
 Teakwood
 Sal wood
 Deodar
 Hardwood
 Ply board
 Particle board

 Teak wood is a most appropriate timber to be used in the construction of buildings.
 Teakwood is naturally durable with good merit and adaptability although it is prone to
attacks of white ants and insects.
 Yet builders choose teakwood for its natural look, durability with long lasting
characteristics.
 Sal wood is another timber material identified as much stronger and quite harder
than teakwood used in building purposes.
 Sal is less prone to termite or fungi attack and can be used for several constructive
purposes.
 Deodar is one of a strongest Indian conifer with less strength and weight than
teakwood.
 Deodar has maintained its good image for durability and style of appearance.
Deodar can be easily cast in any shape, easy to saw.
 Generally used for building & construction in homes and other civil structures.

• Hard wood is another form of wood which is treated thoroughly before use
as it is not durable as much as teakwood or deodar.
• After treated through, wood preservative and polishing on hardwood makes
it suitable for house building structure.
• Ply board is used in buildings for various purposes. They are formed by
pressing together several layers of wood.
• Particle board is made of agro waste, cellulose etc. and blended with
adhesive to make into a solid board.

Defect occurring in timber are grouped into the following five categories :
 Defects due to conversion.
 Defects due to fungi.
 Detects due to insects.
 Defects due to natural forces.
 Defects due to seasoning.

a. Chip Mark : Marks or signs placed by chips on the finished surface of timber.
b. Diagonal Grain : Formed due to improper sawing.
c. Torn Grain : Small depression formed due to falling of a tree.
d. Wane : Pressure of original rounded surface on manufactured piece of Lumber.

Fungi attacks the timber when moisture content is greater than 20% or there is
presence of air and warmth in timber. Some of the important defects due to fungi are
a. Dry Rot : Certain types of fungi attack on wood and convert it into dry form.
b. Wet Rot : Certain types of fungi cause chemical decomposition of wood and convert
timber into grayish brown powder.

The insects responsible for decay of timber are beetles, marine bores, termites.
(i) Beetles
 They form pin-holes of size about 2mm diameter in wood. They attack the sap wood
of all species of hard woods.
 The timber is converted into fine flour-like powder. They usually do not disturb the
outer shell or cover. Hence, timber piece attacked by beetles may look sound till it
completely fails.
(ii) Marine Borers
 These are generally found in salty water. Most of the varieties of marine borers do not
feed on wood. But they make holes or bore tunnels in wood for taking shelter.
 The diameter and length of these holes may go as high as 25mm and 60mm
respectively.
 No timber is completely immune from the attack of marine borers.

 These are popularly known as white ants and they are found in abundance in
tropical and subtropical countries dot these insects live in a colony and they are
very fast in eating away the wood from core of the cross section.
 They make tunnels inside the timber in different directions and usually do not
disturb the outer shell or cover.
 Very few timber such as teak, salt, etc. Can resist the attack of white ants.

 Important among these are shakes: these are cracks which partly or completely separate the
fibers of wood.
 Shakes
 These are cracks which partly or completely separate the fibers of wood. Following are the
different varieties of shakes.
(a) cup shakes
(b) heart shakes
(c) ring shakes
(d) star shakes
(e) Radial shakes
 Rind galls
 Knots
 Twisted fibers

 Rupture of tissues occur in circular
direction.
 Separate one annual ring from the
other.
 Occur due to non uniform growth or
due to excessive bending during a
cyclone weather.

 Cracks which extend from pith to sap
wood in the direction of medullary
rays.
 Occurs due to shrinkage of interior
part of tree.

 When cup shakes cover the entire
ring, they are known as ring shakes
as shown in figure

 These are cracks extending from
bark towards sapwood.
 Formed due to extreme heat or
severe frost during the growth of
trees.

 These are cracks extending from
heartwood towards sap wood .
 similar to star shakes but fine
irregular and numerous.
 Occurs when tree is exposed to sun
for seasoning after being fell down.

 These are peculiar curved swellings
on the body of the tree.
 Timber in this spot is very weak and
are not durable

 These are the basis of branches or
limbs which are broken or cut off
from tree.
 Continuity of wood fibers is broken
by knots, death from a source of
weakness.

 Fibers of wood are twisted in one
direction.
 Caused by twisting of young trees by
fast blowing wind.
(i) upsets
 Wood fibers which are injured by
crushing or compression.
 Due to improper felling of tree or
exposure of young trees to fast
blowing wind.

The different defects which occur due to improper seasoning are as follows:
 Bow
 Case hardening
 Check
 Collapse
 Cup
 Honey-combing
 Radial shakes
 Split
 Twist
 Wrap

 Seasoning of timber is the process by
which moisture content in the timber is
reduced to required level.
 By reducing moisture content, the
strength, elasticity and durability
properties are developed.
 A well-seasoned timber has 15%
moisture content in it.
 Methods of Seasoning of Timber
There are two methods of Seasoning of
timber which are explained below
1.Natural seasoning
2.Artificial seasoning

 Natural seasoning is the process in which timber is seasoned by subjecting it to the
natural elements such as air or water. Natural seasoning may be water seasoning or
air seasoning.
 Water Seasoning
 Water seasoning is the process in which timber is immersed in water flow which helps
to remove the sap present in the timber. It will take 2 to 4 weeks of time and after that
the timber is allowed to dry. Well-seasoned timber is ready to use.
 Air Seasoning
 The process of air seasoning timber logs are arranged in layers in a shed. The
arrangement is done by maintaining some gap with the ground. So, platform is built on
ground at 300MM height from ground stop the logs are arranged in such a way that air
is circulated freely between logs. By the movement of air, the moisture content in
timber slowly reduces and seasoning occurs. Even thought it is a slow process it will
produce well seasoned timber.

• Natural seasoning gives good results but takes more time. So, artificial seasoning of
timber is developed nowadays. By artificial seasoning, timber is seasoned with in 4-5
days.
• Here also different methods of artificial seasoning are there and they are as follows.
• Seasoning by Boiling
• Chemical seasoning
• Kiln seasoning
• Electrical seasoning

 Seasoning of timber is also achieved by boiling it in water for 3 to 4 hours.
 After boiling timber is allowed to drying.
 For large quantity of timber boiling is difficult so, sometimes hot steam is passed
through timber logs in enclosed room. It also gives good results.
 The boiling or steaming process develops the strength and elasticity of timber but
economically it is of heavier cost.

 In case of chemical seasoning, timber is stored in suitable salt solution for some time.
 The salt solution used has the tendency to absorb water from the timber.
 So, the moisture content is removed and then timber is allowed to drying. It affects the
strength of the timber.

 ICE CREAM
 Soft ice cream uses cellulose, the chief constituent of the cell walls of plants and
wood, has a thickener and stabilizer stop this wood product helps the ice cream to
keep its shape.
 Nail polish
 Nail Polish uses nitrocellulose, which is cellulose exposed a nitrating agent, for
strength and quick dry properties will stop essentially, trees give us fashionable
fingers.
 Parmesan cheese
 parmesan cheese also uses cellulose. This is FDA approved, as cellulose. is a
harmless organic matter and helps to prevent shredded cheese from clumping.

 Ink
 Ink incorporates tall oil crossing from hard Pines (subgenus Pinus) close stop some
inks are also made with nitrocellulose. BIC ballpoints will never be the same.
 Cigarette filters
 Cigarette filters use cellulose acetate fibers, one of the earliest synthetic fibers, which
is based on wood pulp cellulose.
 Medicine
 Medicine in the form of quick dissolve tablets often uses refined microcrystalline
cellulose has a pill filler. Play later
 Sunscreen
 Sunscreen is made with plant product like almond, clove bud oil and cocoa butter. A
summer necessity for all.

 Some paints
 Some paints contains hydroxy ethyl cellulose, which is a jelling and thickening
agent.
 Chewing gum
 Chewing gum uses wood chemicals like rosin esters, a solid form of resin obtained
by Pines.
 Tooth paste
 Toothpaste usually contains several different wood components, such as cellulose
gum under xylitol, which is made specifically from Birch trees. Trees keep as
minty fresh.

 Ping pong balls
 Ping pong balls are made from celluloid, which is a composition of nitrocellulose
and camphor.
 Doritos
 Doritos use smoke flavoring made from liquefied and refined lumber mill
sawdust.
 https://www.cif-ifc.org/2018/07/12-uses-of-wood-product-in-everyday-items/

 In this method timber is subjected to hot air in air tight chamber.
 The hot air circulates in between the timber logs and reduces the moisture content.
 The temperature inside the chamber is raised with the help of heating coils.
 When the required temperature is obtained moisture content and relative humidity
gets reduced and timber gets seasoned.
 Even though it is costly process it will give good results strength wise.

 In the method of electrical seasoning timber is subjected to high frequency alternating
currents. The resistance of timber against electricity is measured at every interval of
time.
 When the required resistance is reached seasoning, process is stopped because
resistance of timber increases by reducing moisture content in it.
 It is also called as rapid seasoning and it is uneconomical.

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