KTU CE 204 Construction Technology - Module 1

CONSTRUCTION
TECHNOLOGY
Module 1
Fr. Dr. Bennet Kuriakose
Department of Civil Engineering

Syllabus
Department of Civil Engg., SJCET Palai 2
Properties of masonry materials – review of specifications
Mortar Types – Sand – properties – uses.
Timber products properties and uses of plywood, fibre
board, particle board.
Iron and Steel Reinforcing steel – types –
specifications.
Structural steel specifications
Miscellaneous materials : Glass, Plastics, A.C. Sheets,
Bitumen, Adhesives, Aluminium (only properties,
classifications and their use in construction industry)

MASONRY MATERIALS

Masonry
• Masonry is the building of structures from individual units,
which are often laid in and bound together by a filler material
(mortar, clay etc.).
• Individual units may be of stones, bricks or concrete
blocks
• Most primitive form of construction

Building Stones (a review)
Taxonomy (Classification)
• Geological Classification
– Igneous rocks: rocks formed by cooling and solidification
of magma. Ex. Basalt, Quartzite, granite
– Sedimentary rocks: solidification of sediment deposits.
Ex. Sandstone, limestone, shale, slate
– Metamorphic rocks: formed by change in characteristics
of igneous and sedimentary rocks due to temperature and
pressure. Ex. Gneiss, Schist, laterite

• Physical Classification
– Stratified Rocks: Layered structure (strata). Ex. Slate,
sandstone, limestone
– Unstratified Rocks: do not show stratification. Ex.
Granite, basalt
– Foliated rocks: tendency to split up in certain directions.
Stratified Rock

• Chemical Classification
– Silicious Rocks: Contain silica. Hard and durable. Ex.:
Quartzite, sandstone.
– Argillaceous Rocks: Contain Alumina. Less durable and
brittle. Ex. Slate, laterite.
– Calcareous Rocks: Contain Lime. Ex. Marble, limestone.

Characteristics of good stones (specifications)
1. Strength: to withstand compressive load. (crushing
strength > 100 MPa)
2. Durability: resistance against water, heat, chemicals
etc. for a long duration.
3. Hardness: Resistance against abrasion. (Hardness
coeff. > 14)
4. Toughness: Resistance against impact load and
vibrations.
5. Specific gravity: relative measure of strength. Should
be more than 2.8
6. Appearance: pleasing
7. Dressability: less wastage during dressing.
8. Porosity: should be less porous.

Properties of Common Stones
1. Granite
– Hard and durable
– Compressive strength 80 to 130 MPa.
– Specific gravity 2.6 to 2.8
– Not suitable for carving
2. Basalt
– Very hard and tough
– Compressive strengh 150 to 190 MPa.
– Not suitable for carving

3. Sandstone
– Not very hard
– Comp. strength ~ 60 MPa.
– Ornamental carving
– High specific gravity (> 2.7)
4. Limestone
– Not very hard
– Comp. strength ~ 50 MPa.
– Specific gravity 2 to 2.8
– Flooring, paving, manufacture of cement

5. Laterite
– Wet and soft
– Comp. strength ~ 10-20 MPa.
– Masonry works
6. Quartzite
– Sandstone under metamorphic action makes this
– Dense and strong
– Stratified and chrystalline
– Rubble masonry, aggregates of concrete

7. Marble
– Metamorphic from limestone
– Strongest and very durable
– Can be easily carved
– Comp. strength ~70 MPa
6. Gneiss
– Metamorphic from granite
– Comp. strength > 200 MPa.
– Paving slab, masonry work

Bricks (a review)
Classification of Bricks
• Unburnt brick – sun-dried. Not suitable for
permanent structures. Brittle
• Burnt bricks
1. First Class – table molded
2. Second Class – ground molded
3. Third class – ground molded – less quality.
4. Fourth Class – poor quality and not used for masonry.
They are overburnt. Very brittle. used to make Surkhi

Bricks (a review)
Properties of Bricks
1. Size
– “Modular size”
as per IS 1077:1992
2. Compressive strength
– minimum comp. strengh
3.5 MPa.

3. Water absorption
– Shall not be more than 20% of its weight for 24 hours of
immersion in cold water
4. Efflorescence
– Crystalline deposits of salts
– The efflorescence shall be less
5. General requirements
– Free from cracks and flaws
– Smooth rectangular faces
– Uniform colour

Concrete Blocks
• Otherwise known as Concrete Masonry Unit (CMU)
• size – 390 mm X 190 mm X 29 mm (or 19 mm or 9 mm)
• Size is higher – takes less time for construction.
• Cement + aggregate (ratio normally 1:6)
• 60% fine aggregate and 40 % coarse aggregate
• Water content is very less – compressed to get required
compaction

Classification
• Solid Blocks
– Dense aggregates are used
– Used for load bearing masonry
– Less time for construction compared to masonry
• Hollow blocks
– Hollow part to save material
– Less strength compared to solid block
– Normally used for non-structural parts
(ex. partition walls, parapets)

Fly ash Brick (Content beyond syllabus)
• Raw Materials
– Fly ash
– Cement
– Sand
– Water

AAC Blocks (Content beyond syllabus)
• AAC (Autoclaved Aerated Cement) blocks was developed in
1924 by a Swedish architect
• Contents: Cement, Gypsum, Lime (optional), Fine sand
(optional), water, Aluminium powder (0.05%), Fly ash
(optional)
• Aluminium induced aeration by reacting with Calcium
hydroxide
• Autoclaved –pressure and temperature (200 degrees)

AAC Blocks (Content beyond syllabus)

MORTAR

Mortar
• A paste prepared by adding water to a mixture of binding
material (cement, lime, pozzolana or mud) and fine
aggregate (adulterant) ( sand, M-Sand or Surkhi) .
• Latin “mortarium” meaning crushed
• Used to bind masonry, plastering and increase fire
resistance (firestop mortar)
Taxonomy (Types of Mortar)
• Based on Bulk Density
– Heavy Mortar: bulk density ≥ 15 kg/m3. Heavy
aggregates are used.
– Light Mortar: Bulk density < 15 kg/m3. Light weight
aggregates are used.

Mortar
• Based on Type of Binder
– Cement Mortar: proportion of cement is selected based on
the purpose. High strength and durability. Proportion vary
from 1:6 to 1:2.
– Lime Mortar: Lime is used as binding material. Normal ratio
is 1:2. It has high plasticity than cement mortar.
• Hydraulic Lime (HL) mortar – sets by hydration (water – lime
reaction).
• Non-Hydraulic Lime (NHL) mortar – sets by carbonation – carbon
dioxide is required. Cannot set under water/inside thick wall

Mortar
– Gypsum Mortar: gypsum is the binding material. Used in
ancient monuments like pyramids.
– Mud (clay) mortar: used for low cost housing
– Gauged (lime – cement) Mortar: Lime + cement + sand
– this will be plastic and have sufficient strength.
– Surkhi Mortar: Surkhi (powdered burnt clay brick) + Lime
• Not used for plastering
• Less durable.
• Cheap

Mortar
• Based on Nature of Application
– Masonry Mortar: used for bonding agent in masonry.
More strength is required.
– Finishing Mortar: used for plastering and other finishing
works. Much strength is not required. Durability should be
high
• Special Purpose Mortars
– Firestop Mortar: act as a shield for fire proofing (act as
fireproof shield). Aluminous cement + surkhi of fire
bricks firestop mortar. Used in fire places, ovens etc.
– Lightweight Mortar: for sould proof and heat proof. Saw
dust (or asbestos fibre or coir fibres) + cement.

Mortar
– Packing Mortar: cement+sand or cement + loam (a type
of soil). Used to pack the oil wells.
– Sound Absorbing Mortar: for sound proofing.
Cement/lime/gypsum / slag + porous aggregates
(pumice). Bulk density 6 to 10 kN/m3 .
– X- Ray shield Mortar : X- ray room walls and ceilings are
plastered. Fine aggregates from heavy rocks are used.
Bulk density ~ 22 kN/m3 .
– Chemical Resistant Mortar: reduce chemical attack on
structures. The content depend on the type of attack to be
resisted.

Mortar
Uses of Mortar
1. Used to provide the joints for masonry.
2. Used for plastering walls and for pointing masonry work.
3. Used to act as an adhesive in binding the bricks or stones
together into a solid mass.
4. It improves the appearance of a structure.
5. Plaster can cover up nonstructural cracks.
6. Open joints in brickwork and stonework can be hidden by
plaster.
7. Increase fire resistance (firestop).

Mortar
Properties of Good Mortar (Specifications)
1. It should develop good adhesion with building units
2. It should be efficient to resist water or chemical penetration
3. It should be capable of developing the designed stresses.
4. It should be workable
5. It should be durable
6. It should be inert with other materials in contact
7. The mortar joints should be strong and capable of resisting
cracks.
8. It should set quickly to achieve the speed in construction

Mortar – extra info (content beyond syllabus)
How to calculate amount of cement and sand?
• Let‟s say, the proportion of cement and sand in mortar is 1:X,
where X is the volume of sand required.
• Then, the volume of sand required for 1:X proportion of
1m3 cement mortar will be
• Volume of cement will be calculated as:
• Since the volume of 1 bag of cement is 0.0347 m3, so the
number of bag of cement will be calculated as
• Water-cement ratio – 0.4 (i.e., 20 L of water for 1 bag
cement)

Sand
• Sand is loose particles of hard broken rock.
• Diameter ranges from 0.06 mm and 2 mm.
• Main content is Silica (SiO2)
• Gives strength and integration to concrete and asphalt mixes
Properties
1. Should be chemically inert
2. Free from organic matter. 3 – 4 % clay is permissible.
3. Should contain sharp and angular grains.
4. Should be well graded.
5. Should not contain salts (which will absorb moisture or
induce corrosion).

Sand
Uses
1. Bulk: it does not increase the strength of mortar. It acts as
an adulterant.
2. Setting: for NHL mortar, the carbon dioxide is absorbed
through the voids of sand to enhance setting.
3. Shrinkage: Prevent excessive shrinkage or mortar thereby
limiting shrinkage cracks.
4. Strength: Contributes to the strength of concrete and
asphalt mixes.
5. Surface area: it subdivides the paste of binding material
into a thin film and thus offering more surface area for its
spreading.

TIMBER PRODUCTS

Timber
• Denotes wood which is suitable for building or carpentry.
• Wood is natural and renewable product from trees.
• Used for buildings, bridges, utility poles, piles, floor, trusses,
flitched beams and roofs.
• Natural and engineered wood products (Plywood, fibre
board, particle board etc.) are used.

Plywood
• Veneer refers to thin slice of wood that are practically peeled
of the wood. Thickness < 3 mm. the wood grain will be
oriented along a single direction.
– Rotary veneers (peeling operation)
– Crown cut Veneers (slicing operation)
• Plywood is a sheet material manufactured from thin layers
(plies) of veneer that are glued together with adjacent layers.
• The plies are pressed by hydraulic system and finished.
Veneer
plywood

Plywood
• Adjacent layers of plies have their wood grain rotated up to
90°.
– Gives strength in both the directions.
– Reduce expansion and shrinkage
• For thicker product, the adjacent plies have wood grains
rotated in consecutive steps of 45° or 30°.

Plywood
Properties (Specifications)
• Uniform tensile strength in all directions.
• Light weight compared to wood.
• Not easily affected by moisture.
• Expansion and shrinkage is very low
• Can be bend to some extend.
Uses
• Partition walls
• Concrete formwork
• Railway coaches
• Panelling
• Floors and roofs for home
• Furniture and doors

Particle Board
• Also known as chipboard
• It is wood product manufactures from wood chips, sawmill
shavings or sawdust bound with synthetic resins as binder.
• Pressed and extruded after binding.
• Cheaper, denser and uniform than conventional wood and
plywood
• Strength is less compared to plywood.
• Uses are same as that of plywood

Particle Board
Manufacturing Process
• The raw material particles are fend into a disc chipper to get
into required size
• The particles are then dried and screened for oversized and
undersized particles.
• Resin is mist-sprayed onto the particles to coat all the
surfaces of the particles.
• Then the fibres are laid as „carpet‟ and cold pressed.
• Face veneers are added if necessary

Fibre Board
• It is wood product manufactures from wood chips, sawmill
shavings or sawdust bound with synthetic resins as binder.
• Types:
– Low Density Fibreboard (LDF) or Particle Board
– Medium Density Fibreboard (MDF)
– High Density Fibreboard (HDF) or Hardboard

Fibre Board
Manufacturing Process (MDF and HDF)
• wood chipping: fresh or recycled wood material is cut and
sorted to small pieces of similar size.
• Chips are washed to remove things such as dirt and sand.
Metal scraps such as nails can be removed with a magnet
placed over a conveyor belt.
• chips are then steamed to soften them for defibration.
• Small amount of paraffin wax is added to the steamed chips
and they are transformed into fluffy fibers in a defibrator
• They are sprayed with adhesives
• The chips are layers as „carpet‟ and hot pressed.
• Face veneers are added if necessary.

Rubberwood (content beyond syllabus)
• Manufacturing process:
– sawing
– Treatment with pressurized immersion
in boron preservatives
– kiln-drying to diffuse the chemicals and to control
moisture content.

IRON AND STEEL

Iron and Steel
Based on the carbon content in iron
• Wrought Iron < 0.15%
• Steel 0.15% to 1.5%
• Cast Iron 1.5% to 4%
Based on carbon content steel:
• Mild steel 0.15% to 0.3%
• Medium carbon steel 0.3% to 0.8%
• High carbon steel 0.8% to 1.5%

Reinforcing Steel
• mesh of steel wires used as a tension device in reinforced
concrete and reinforced masonry structures to strengthen
and aid the concrete under tension.
• The concrete is strong in
compression but weak in tension
– the tensile part of the structure
is strengthened with rebars
(reinforcement bars)
• Surface of rebars is often
deformed to have better bond
with concrete.
• Availabe diameters – 6, 8, 10,
12, 16, 20, 25 and 32 mm.

Reinforcing Steel
Specifications of Reinforcing Steel
• Same coefficient of thermal expansion that of concrete
• Should have sufficient ductility
• Should be bendable (should not break during bending and
rebending)
• Corroded bar should not be used. The corroded part need to
be removed before use.
• Should have sufficient bonding with concrete (ribs are
provided)

Reinforcing Steel
Classifications
1. Mild Steel Bars
• No ribs – bonding is less
• Ductile than any other types of steel
• Typical yield stress – 250 MPa.
• Recently very rarely used
2. Cold Worked Bars (TOR steel)
• Cold working involves twisting (CTD bars)
or drawing the mild steel at room
temperature.
• This eliminates the plastic plateau of mild
steel and increases tensile strength (to
400 MPa).
• Less ductile than mild steelDepartment of Civil Engg., SJCET Palai 46

Reinforcing Steel
3. Hot Rolled Bars
• Hot rolling is done in the mills which involves giving it
deformations on the surface i.e. ribs so that it can form
bond with concrete.
• The mild steel bar is heated and rolled to get Hot rolled
bars
• High tensile strength (400 MPa).
Cold Worked and Hot Rolled Bars are together known as HYSD
(High Yield Strength Deformed ) bars.

Reinforcing Steel
4. TMT Bars
• First bars are passed through hot rolling system, then
to a water cooling (quenching) system. (Outer
temperature suddenly reduced from 900 to 280 °C,
inner layer still at 900 °C)
• Allowed to cool down slowly (cooling bed)
• The outer rim is tough and brittle; inner is soft and
ductile.
• High tensile strength (upto 550 MPa)

Reinforcing Steel
Plasma Coated TMT Rebars

Reinforcing Steel
5. Prestressing (PC) Strands
• High carbon steel (High strength)
• Treatments:
• Cold Working
• Stress relieving – heat to 350 °C and cooling down
• Strain tampering – heating under tension
• Coated for durability – galvanisation or epoxy coating
• Tensile strength ~1800 MPa.

Structural Steel
• Structural steel is used for buildings, factories, vehicles,
ships or structural members (beam, column etc.)
• Made by hot rolling or cold formed (cold form steel)
Hot rolled sections
Cold formed sections

Structural Steel
Market Forms (Specification IS 808: 1989) and uses
1. I Section
– Has web and flange
– Designated by overall height and weight per meter
– ISJB, ISLB, ISMB, ISWB and ISHB (as per Indian
standards)
– Used for beams, trusses and girders

Structural Steel
2. L (Angle) Section
– Has two legs connected at right angles
– Two types:
• Equal angles (length of legs are equal)
• Unequal angles (lengths of legs are not equal)
– Designated by length of legs and thickness of leg (ISA)
– Used for trusses, columns, small beams.

Structural Steel
3. C (Channel) Section
– Has a web and two equal flanges
– Designated by height of web and width of flange
– ISLC and ISMC
– Used for beams and purlins

Structural Steel
4. T (Tee) Section
– Consist of a web and a flange
– Designated by overall depth and width
– Used for beams, purlins, bridges, built-up sections
– ISJT, ISLT, ISNT and ISHT

Structural Steel
5. Tube Section
– Square or Rectangular cross section
– Used for beams, columns, truss and purlins.
– ISTUB

Structural Steel
6. Pipe Section
– Circular cross section
– Used for columns, truss and purlins.
– Light medium and heavy
– ISPIP
– Designated by external diameter

Structural Steel
6. Flats
– Used for grill, window, gate etc.
7. Squares
8. Rounds
9. Plates
– Used for built up section, water tank,
Ship hulls, floors, built up sections etc.

MISCELLANEOUS MATERIALS

Glass
• Silica is the main constituent
• Added with sodium and potassium carbonate to bring down
melting point
• Lead oxide is added for durability
• Manufacturing process:
– The raw materials are ground and seived
– Mixed in the specific proportion and melted in furnace
– Blowing, flat drawing, rolling, floating and pressing

Glass
Properties
1. Transparency: essential quality. Can be altered by adding
admixtures.
2. Strength: Glass is a brittle material with low strength.
However, the strength can be increased by different
processes.
3. Quality: Glass should be clean, free from blisters,
scratches, bubbles etc. that impair the visibility.
4. Waviness: The glass should not show any distortion of
light.

Glass
5. U-value specifies how much heat the glass can transfer. R-
value is the inverse of U-Value. A lower U-value (higher R-
value) indicates better insulation property of the glazing.
6. Bending Strength: It should be capable of taking bending
stresses according to the application.
7. Thermal expansion: The thermal expansion should be
very less.
8. Chemical Resistance: Should be resistant to chemicals
and salts.
9. Abrasion Resistance and Hardness: should be
sufficiently high.

Glass
Types of Glass (Based on Composition)
1. Soda-lime Glass (Soft Glass):
• obtained from the fusion of a mixture of silica, lime, soda and
alumina.
• Powdered glass also may be added
2. Lead Glass:
• obtained from the fusion of a mixture of silica, lead and
potash.
• Powdered glass is added.
• It is used for cut glass work, electric bulbs.
3. Borosilicate (BOROSIL) Glass:
• Obtained from the fusion of a mixture of silica, borax, lime
• Withstand high temperature

Glass
Types of Glass (Commercial Form)
1. Flat (Float) Glass:
• Made by float process
• It has a uniform thickness and makes the base for more
advanced types of glass through further processing.
• This glass tends to break into long shards.
• Application: home window, instruments, bottle etc.

Glass
2. Toughened (Tempered) Glass:
• The cooling process during manufacturing creates
counteracting stresses to get more harder glass
• If it breaks, the glass will shatter into small, square
fragments rather than shards, decreasing the risk of
injury.
• Uses: Windows, mobile phones, vehicles.

Glass
3. Laminated Glass:
• Laminated glass is held together by an interlayer,
meaning that it will not shatter on impact and remain
integral
• Highly ductile
• option where increased security may be needed.
• Uses: front doors, store window fronts or car
windscreens

Glass
4. Patterned Glass:
• passing heated glass through rollers
containing a regular pattern to be
imprinted upon the glass.
• bathroom windows or doors where
total transparency is not required.
5. Tinted Glass:
• Small amounts of metal oxides are
added to the glass composition to give
tinted glass its characteristic colours

Glass
6. Mirrored Glass:
• Mirrored glass is quite simply a mirror –
and can be produced in all sizes, from
small bathroom mirrors to full-
length wardrobe doors.
• It is made by applied a metal coating to
one side of the glass, typically made of
silver, chrome, gold or aluminium.
7. Coated Glass:
• Coated glass is modified flat glass to give
it specific characteristics, for example to
make it insulating and resistant to infra-
red.
• It is commonly used for double glazed
windows to improve home insulation.

Glass
8. Bullet-proof Glass:
• It consists of a number of glass layers
alternating with vinyl-resin plastic (or
polycarbonate) layers, pressed
together.
• The inner glass plates are thick and
cooling process is carried out under
specially controlled manner.
9. Fibre Glass (Glass wool):
• it is in the form of glass fibres which
are soft and flexible.
• It is highly resistant to wear and tear.
• It is mainly used for all kinds of thermal
and sound insulation works

Plastics
Natural or synthetic organic material, which has the property of
being plastic at some stage of its manufacture when it can be
moulded to required size and shape. It is highly durable and
cost effective

Plastics
Classification (Taxonomy)
• Based on Structure
– Homogenous Plastic - contains only chain of carbons
– Heterogeneous Plastic -contains chain of carbons,
oxygen, nitrogen and other elements
•Based on Thermal Property
– Termo-Plastic - soften on heating & harden on cooling.
• Process of softening & hardening can be repeated any
number of times : recyclable
– Thermosetting Plastic -
• set into permanent shape. Reheating will not soften
them. Used for making paints & varnishes and thermo-
resistant objects

Plastics
• Based on Physical and Mechanical Properties
– Rigid Plastics- Modulus of elasticity (E) - high, maintains
shape under external pressures and at increased
temperature
– Semi rigid- E-medium, regain orginal shape & size after
removal of pr
– Soft plastics- E- low, slowly regain orginal shape & size
after removal of pressure
– Elastomers- E-very low, deform 10times orginal
dimension, but return to orginal shape & size after removal
of pressure

Plastics

Plastics
Properties
• Appearance : some are transparent or translucent. Can be
pigmented
• Chemical resistance
• Dimensional stability – less shrinkage, creep
• Brittle – lack ductility.
• Durable
• Insulation (thermal and electrical) – thermo-setting plastics
• Fire-resistance: thermo plastics are highly combustible.
• Melting point: is very low

Plastics
Uses
• Flooring
– PVC and polyethelene is used
– Less wear and tear
• Insulation
– Polyurethane spray is used for thermal resistance
– Polyurethane foam is also used
• Roofing
– Two layers of plastic materials are used.
– One pare is vinyl other is polyurethane

• Wall
– Insulated panels – polystyrene is used
– PVC/acrylic is often used for partitions
• Pipes
– PVC and Acrylonitrile Butadiene Styrene (ABS)
• Windows and doors
– PVC and FRP (fibre reinforced plastic) are used

Asbestos Cement (AC) Sheet
• Asbestos is naturally occuring fibrous mineral (silicate)
• Asbestos products are made by mixing asbestos and
cement
• Sheets, pipes and insulators
Properties of AC sheets
• Can be cut into pieces
• Holes can be drilled without breakage
• Excellent thermal and electrical insulator
• Fire-proof
• Excellent chemical resistance
• Melting point is > 1200 degree Celsius
• Highly brittle

Asbestos Cement (AC) Sheet
Uses of Asbestos
• Roofing material
• Asbestos sheets are used for flooring and partitions
• Insulation lining for fuse box and switch box
• Insulating boilers, geezers, furnaces etc.
• Preparing fire-proof clothes

Bitumen
• Bitumen is a binding material obtained as waste product of
fractional distillation of crude oil.
• Also called “coal tar” or Asphalt
• Differentiated with “tar” which is obtained from wood or coal
• Obtained as solid or semisolid state

Bitumen
Classification (Categories)
• Straight run bitumen: has definite viscosity without further
treatments
• Blown Bitumen: modified by passing air under pressure at
high temperature. Used for roofing, damp-proofing, pipe
joints, heat insulating materials.
• Cutback Bitumen: viscosity is reduced by adding diluting
agents like gasoline, kerosene & light oil, used for road
repairs & soil stabilization
• Plastic Bitumen: consists of bitumen , thinner & a suitable
filter in plastic form. Used for filling cracks in masonry for
stopping leakage
• Bitumen Emulsion: Bitumen with water. Soil stabilisation

Bitumen
Properties
• Adhesion: adhere with solid surface. Presence of water
prevent adhesion.
• Resistance to Water
• Hardness: Penetration test is conducted to find out
hardness.
• Viscocity: The flow properties are important at given
temperature.
• Softening point: Temperature at which the bitumen attains
flowability. Should be high.
• Ductility: solid bitumen should have high ductility to be used
in Asphalt concrete.
• Fire Point: Temperature at which bitumen catch fire. Should
be high.

Bitumen
Uses
• Used for roofing felts (shingles)
• Asphalt concrete
• Coating roofs, walls and floors
• Damp proof and leak proof coats
• Paints
• Filling cracks in masonry

Adhesives
• Glue- general term used to join two or more surfaces to form
a single units
• Used in tile fixing, timber construction, concrete, paints etc.
Types
1. Natural resin adhesive
Asphalt, shellac, ceresin (purified ozokerite)
used for joining papers
2. Rubber glue
dissolving rubber in gypsum,
joining plastics, glass, rubber

Adhesives
3. Starch glue
prepared from vegetable starch,
joining paper & inferior quality ply wood
4. Sodium silicate (water glass) glue
fused mass of sodium silicate
used to form paper boxes & fibre boards
5. Synthetic glue
resins like melamine resin, phenolic resins, urea
resins, polyvinyl resins etc
strong , fire proof & water proof
used in ply wood

Adhesives
7. Casein Glue
Obtained from skimmed milk, which is washed, pressed &
dried
Strong & water proof glue for wood joints
8. Animal glue
Obtained by boiling waste pieces of animal skin & bones
with hot water
superior variant glue
used in manufacture of plywood 7 laminates

Adhesives
Properties
1. High tensile strength
2. High cohesive strength
3. Durability
4. Should easily spread
5. Should not be affected with water.
6. Optimum time to develop bond
Uses
1. Manufacture of veneers, plywoods, fibreboards
2. Fixing wall and ceilings, floor coverings, finishes etc.
3. Joining rubber, plastic, glass etc.
4. Used in paints and distempers
5. Joining rebars with hardened concrete

Aluminium
• It is a silvery-white, soft, nonmagnetic and ductile metal
• It is the third most abundant element after oxygen and silicon
on earth.
• the most abundant metal in the crust.
Properties
1. Good conductor of heat and electricity
2. Silvery white with bright lustre
3. Non-magnetic
4. Malleable and brittle
5. Light weight (unit weight 2500 kg/m3)
6. Corrosion resistant by property of “passivation”
7. Naturally soft, however, alloys are as good as steel

Aluminium
Forms (Types) of Aluminium and Uses
1. Casting-based
– Molten metal is forced under high pressure into mould
cavity
– Baluster-head, hardware fittings, decorative grills
2. Extrusion-based
– For making fixed cross sectional profile – pushed
through die
– Door and window frames, handles, tower bolts, curtain
rails
– Structural steel
3. Foil
– Wall paper, water proofing sheet and food preserve

Aluminium
4. Powder
– To produce paints against corrosive environment
5. Sheets
– False sealings, roofing sheets, rain water articles (gutter,
spouts )
– Prefabricated houses

KTU CE 204 Construction Technology - Module 1

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KTU CE 204 Construction Technology - Module 1