Timber.pptx

TIMBER
Timber refers to wood that best suitable for engineering work or for building work.
WOOD
Wood is a material by which we can shutter, and used for making goods like furniture and many
other material which is more attractive and affordable than other material.

Wood is commonly grouped into two categories which are representative of the basic botanical
classification of the two families of trees.
• Hardwoods - Angiosperms (broadleaf, mostly deciduous), for example: oak, maple, walnut.
• Softwoods - Gymnosperms (mostly conifers), for example: pine, Douglas fir, white fir,
hemlock, etc.
Hardwood Soft wood

Types of trees
 Exogenous Tree
 Endogenous Tree
Endogenous Tree:
The tree which having small stem and generally the height is straight and never seen many
branches and timber obtained from that tree is generally never used for engineering work.
Example of Endogenous tree: Bamboo, Cane, Palm etc
Bamboo Trees
Palm Tree

Exogenous Tree:
The tree which having lots of branches and generally circumference of stem is big in size. Some
tree falls their leaves in some month of a year.
The Exogenous trees are further classified into two categories
Conifer:
These are evergreen trees and having light in color, light in weight and soft wood which is weak in
nature so we can’t use the wood of these tree.
Example of Conifer Tree: Deodar and Pine etc
Deciduous:
These are hard wood tree and leaves of these tree falls in autumn and come back in spring. These
are best and useful for engineering work because of hard wood property.
Example of Deciduous Tree: Sal, Teak, Oak,

Structure of wood
•Macrostructure and
•Microstructure
Macro-structure of wood
The structure of wood which can easily seen by naked eye or with small magnification is called macrostructure of wood.
The macrostructure having pith, Heart wood, sap wood, cambium layer, inner bark, outer bark and medullary rays.
3. Structure of a Wood

PITH: Pith is the inner most portion of the tree, its size, shape and color varies from tree to
tree. It is also called medulla, it is responsible for the nutrition the plant at young age and after a
long time the pith dies.
HEART WOOD: It is annual inner rings which is outer portion of pith and formed annually. it
dead after formation of outer ring so dark in color and responsible for the stability of tree, due to
hard property.
SAP WOOD: Sap wood is the outer annual rings and it is active part which moves sap upward.
Due to activeness it is light in color and indicates freshly made.
CAMBIUM LAYER: It gives sap to sap wood, it contains fresh shape which is responsible for the
life of tree. It is middle part of sap wood and inner bark, if bark is removed then cambium fail to
provide sap to tree, and tree would be dead.
INNER BARK: It protect the cambium layer.
OUTER BARK: It is outermost part of tree which protect tree from any damage and withstand
property with any weather, it also protect inner portion. It is also called cortex.
MEDULLARY RAYS: These are radial rays formed from pith to cambium layer. It holds the sap
wood and heart wood. In some tree it can be seen as broken.

Micro-structure of wood
The wooden structure which is seen by microscope or any other magnifying instrument is called
microstructure because it is very small in size which can’t be seen by naked eye . The dead and
living part of wood is seen and studies in the microstructure.
4. Microstructure of Wood

Anisotropic - The properties of wood are different in each of the structural directions. For
example, dimensional change in response to changes in the moisture content of wood
(shrinking/swelling) is much less in the longitudinal (axial) direction than it is in the transverse
directions (tangential and radial), and the dimensional change in the tangential direction is typically
about twice as great as in the radial direction.
Orthotropic - A specific type of anisotropy, with 3 orthogonal planes of symmetry.
Hygroscopic - Wood has an affinity for water, meaning that it readily picks up (adsorbs) moisture
from and loses (desorbs) moisture to the atmosphere.
Density - Measure of the amount of wood substance, defined as the weight per unit volume (units
of lb/ft3, g/cm3, or Kg/m3 ). Both the weight and volume of wood vary with the moisture content
of wood. Therefore, when density is measured the moisture content of the wood must be noted.
Specific Gravity (SG) - The density of a material relative to the density of water. The scientific
convention is to base the SG on the oven-dry mass and the volume at a saturated moisture
content, also known as the green moisture content. In some literature SG is also reported as based
on an overn dry mass and a volume at 0% MC or 12% MC.

Mechanical Properties - Strength and stiffness are the main mechanical property categories
(Table 2). They are a measure of the load (force) wood can carry before it is permanently deformed
or it fails (units of psi or Kpa).
• Strength decreases with increases in temperature. The effect is small and reversible at
temperatures below 100°C. Above 100°C thermal degradation of the wood occurs and dramatic
reductions in strength are possible (time dependent).
o Toughness - Measure of the capacity of a material to absorb shock energy (that is, the ability to
resist impact loading). Toughness is the strength property most sensitive to decay.

o Compression Strength – Measure of how much load wood can support when stressed in the
direction parallel to the grain.

o Tension Strength – Measure of the capacity of a wood to resist a tension stress applied
parallel to the grain.
o Modulus of Rupture, MOR (Bending Strength) – The strength of a member loaded in
bending.

Stiffness – Measure of flexibility
o Modulus of Elasticity, MOE (Bending Stiffness) – Measure of the load on a beam that will cause a
deflection of 1 inch (units of psi).

Factors that influence mechanical properties include:
• Moisture Content – Wood is strongest when completely dry, as the moisture content of wood
increases, the strength of wood decreases.
• Density – As a general rule, high density woods are stronger than low density woods.
• Structural Direction – Strength varies depending on the direction relative to the grain in which
the load is applied.
• Time or Duration of Load - Wood gradually changes shape over time when it is loaded. This
deformation is named creep and it may become permanent if the load continues for a long time.
The duration of load factor used in timber design is related to the creep phenomenon. Strength
decreases with duration of loading. Long term loading (10+ years) may reduce strength in bending
as much as 60%.

Permeability – A measure of the ease with which fluids flow through wood. Wood is much more
permeable in the longitudinal direction than in the radial or tangential direction. Exposed end grain
readily takes up water whereas water penetrates very slowly through side grain.
• Electrical Conductivity – Wood is a good insulator when it is dry but not when the moisture
content is above 30%. The electrical conductivity of wood increases as the moisture content of
wood increases.
• Thermal Conductivity – Wood is a good thermal insulator. Thermal conductivity of wood is
approximately 0.75 Btu/hr-ft2/oF/in (steel is approximately 300). The thermal conductivity of wood
is in part dependent on the amount of void spaces in wood. High density woods are more
conductive than low density woods because the high density woods have fewer void spaces.

Variability – Properties vary because of genetic factors, growth factors and manufacturing
methods. Examples of these factors include:
o Between species - different anatomical characteristics including the amount of cell wall
substance (which defines density)
o Between trees of the same species - genetic and growth factors
o Between boards of the same tree - grain orientation, knots, relative amounts of heartwood and
sapwood
o Within one board - juvenile and reaction wood zones, and changes in annual ring orientation
Natural Durability – The resistance of wood to the biological degradation of certain insects and
decay organisms is termed durability. This natural durability of wood is directly related to the
type and proportions of chemicals within the heartwood zone of a tree.

Seasoning of Timber
• By seasoning of timber, it is understood that the controlled reduction of moisture from the
wood.
• The moisture content of standing trees may be as high as 40-60 percent or even more.
• After careful seasoning, it could be brought down to 4-6 percent by (kiln seasoning) or 14-16
percent by (air seasoning).
• As already said trees contain a lot of moisture in the standing condition. The mode of
occurrence of water in wood issue is rather complex and must be understood thoroughly.
• The wood tissue stores water in cell walls and the cell cavities.

Objectives of Seasoning of Timber.
We may Summarize the objectives of seasoning of timber in five sentences:
1. Reduces much of the useless weight of timber;
2. Increases its strength considerably;
3. Improves the workability of the timber;
4. Decreases the chances of development of shrinkage defects, and,
5. Increases the life of timber, i.e. makes it more durable.

Methods of Seasoning of Timber.
At present timber can be seasoned by a number of methods. These can be conveniently
discussed under two headings:
Seasoning of Timber
Natural Seasoning Artificial Seasoning

Natural Seasoning
Natural Seasoning
Air Seasoning Water Seasoning

• This is as yet the most common process of seasoning of timber used throughout the world.
• In this process, timber sleepers, planks, etc., cut from the wood logs are stacked in the open
air.
• This is as yet the most common process of seasoning of timber used throughout the world.
• In this process, timber sleepers, planks, etc., cut from the wood logs are stacked in the open
air.

(a) Stock ground: It should be level, free from debris and on dry land. It may be a few “cm”
below the ground level.
(b) Stack Pillars: These are constructed at regular intervals out of bricks or masonry
or concrete and may be of 50 cm height from the ground level. Their top surfaces should be flat
and level with each other.
(c) Stack Proper. These are made of sawn timber shapes (sleepers, planks). One stack should
have timber of one shape and same length and width.
The timber shape to be seasoned is stacked in layers in such a manner that:
enough space is left between one layer and another layer above it;
enough space is left between one part and another part in the sum layer:
enough space is left between one stack and another stack.
The stack length and height depend upon the length of the wood part being seasoned. A single
stack may be 3 to 4 meters in height.

The advantages of natural (air) seasoning are:
 It is highly economical;
 It requires little supervision;
 It is applicable to thicker timber parts as well as a thin section.
Disadvantages of Air Seasoning:
Among the major disadvantages, following are more important:
 It is a very slow process;
 It keeps the valuable land and timber blocked for longer periods (and hence in some cases
may be uneconomical).
 Moisture content cannot be brought below a certain limit (16-17 percent).
 Seasoning is not always uniform in all the sections of timber.

Water Seasoning of timber.
• This is a process of natural seasoning of timber that gives good results with logs of freshly cut
trees.
• When the logs are placed in running water, the sap from the cells can be easily washed out. In
place of sap, the cells get filled with ordinary water.
• When such logs are taken out, and wood from them placed for air seasoning, it takes
comparatively less time to become dry.

This is the modern method of seasoning any type of timber in a short time.
It involves drying the timber in a specially designed kiln where there is perfect control over
temperature, humidity and air circulation.
With the help of kiln seasoning of timber, it is possible to reduce the moisture content to as low
level as 6 percent.
Artificial Seasoning
Artificial
Seasoning
Boiling Chemical Kiln
Progressive
Compartmental
Electrical

1. Boiling: This is also a quick method of removing sap from within the cells. The timber to be
seasoned is immersed in water, and the water is raised to boiling temperature.
It is kept boiling for four to five hours. The sap is washed out by this process.
On placing in the air, such boiled timber dries quickly. But, at the cost of the strength and elasticity of the
fibers.
2. Chemical Seasoning of Timber (Salt Seasoning).
This may be grouped under processes of artificial seasoning.
In this method, the timber piece to be seasoned is treated with a chemical solution like sodium
chloride, sodium nitrate or urea.
The essential quality of such a solution is that it reduces the vapour pressure on the surface of
application.
Once such a treated timber is exposed to natural drying, it is the water (sap) from the inner
cells mat moves to outer cells at lower vapour pressure.
The wood surface remains moist while moisture from the interior goes on diffusing to the
exterior.
In other words, chemical seasoning of wood enables the timber to dry first from inside.
It is definitely an advantage as it prevents the risk of cracking of outer shell.

3. Electrical Seasoning of Wood.
It is of theoretical importance only. Dry wood is a non-conductor of electricity.
But when a high alternating current is passed through a piece of green timber, heat generated is
enough to dry out the moisture of the cells which do conduct some electricity.
In this way, the timber pieces are dried quickly. The technique involves costly equipment, and
even the consumption of electricity is so high that the process is uneconomical.
Moreover, heating of cell walls causes considerable weakness in them.
•When it forms a part of a living tree, it is called standing timber
•When the tree has been felled, it is called rough timber
•When it has been sawn to various market forms such as beams, battens, planks etc, it is
called converted timber

Defects in Timber
Defects in timber may be defined as, any undesirable character -natural or artificial- that lowers its strength, durability
or quality.
Defects
Natural Artificial

Natural
Knots
Cross Grain
Rindgalls
Reaction
Wood
Shakes

Knots
A knot marks the position of growth of a branch on the tree. On the cut board, it is most easily
marked by its conspicuously darker appearance and harder character.
A knot is essentially a discontinuity in the timber and hence a place of weakness.

Shakes
In simple they are the cracks developed in the timber, These natural cracks may result from:
• Shrinkage on aging of the tree;
• Due to movement caused by wind action in the growing tree;
• Freezing of sap in the cells during its ascent.

Cross Grain
In fact, a minor slope (of grain) may be seen in most trees. It may be quite harmless. The slope of grain
becomes harmful (or a defect) when it exceeds specified limits.
This is because the strength properties (especially Compressive and tensile strength) are closely related to
the direction of the grain vis-a-vis direction in which the load is applied to the timber.
The slope of grain is determined easily from a simple relationship:
Slope = e / l.
Where, e = max. height (in between planes)
l = Length along the same plane

Rindgalls
Grade Allowable Cross-Grain
Standard Grade 1 in 15
Select Grade 1 in 20
Common Grade 1 in 12
A rindgall is simply a highly thickened, enlarged wood cover developed over an injured part of the tree.

Decay of Timber
Timber decay (rot) is caused by a biological attack within the wood by certain species of fungi. The fungus can
lie dormant in the timber for years until the right conditions present themselves. The conditions needed are
oxygen, moisture and nutrients, with moisture being the critical component
Dry
Rot
• Timber
tissues
to dry
powder
Wet
Rot
• Disintegration
of tissues
Insects
•Decomposition
due to certain
insects

Dry
Rot
Turning out timber tissues to almost dry powder by fungi is called dry rot.
Example: Fungi: Mushroom, Spongy Plant
Prevention:
1. Well seasoned timber should be used
2. Timber should be used where there is free circulation and access of air
Remedy:
1. Timber should be well painted with a solution of copper sulphate.
2. The high-temperature of seasoning of kiln helps in killing the fungus.

Wet
Rot
The Disintegration of tissue in timber due to alternate wetting and drying is called wet rot
Prevention:
All timber for exterior or underground work should be first properly seasoned and then
coated with tar to keep out the dampness.
Remedy:
The best remedy for treating wet rot is by using a suitable preservative.

Insects
Certain insects like Carpenter ants, termites, bark beetles and wood borers causes decay in
timber
They build up mud tunnels to keep their movement covered and continue their activity of
eating into the wood under surface.
Prevention:
1. Damp proof coating.
2. Cement mortar in joints.
3. Well seasoned wood.
Remedy:
1. Suitable preservatives
2. Providing copper bottom to wood which comes in contact with water.

Carpenter ants
Bore beetles
Termites

Alternate Materials for Wood
Paints: It is a mixture of pigments and binders generally available in liquid state.
Pigment: A pigment is a colored material that is completely or nearly insoluble in
water; these are inorganic in nature.
Binders: Substance used to mix/bind other materials together
Applications:
1. Paints applied to buildings gives aesthetic look.
2. Paints on metal to avoid metal decaying.
3. A layer of paint over varnish is applied to wood to avoid decay of timber.
4. Floor and Roof paints provide cooling and heating control in the homes.
Types:
1. Oil bound paints 6. Enamel paints
2. Zinc Paints 7. Emulsion Paints
3. Aluminum paints 8. Alkyl resins
4. Cellulose paints
5. Fire proof Paints

Varnish: Varnish is a solution of resin in either oil, turpentine or alcohol. It dries after applying,
leaving a hard, transparent and glossy film of resin over the varnished surface.
Types:
1. Oil Varnish
2. Turpentine Varnish
3. Spirit Varnish
4. Japans
Applications:
1. Mostly used for wood to provide shiny surface and to protect wood from decay.
2. Varnish is also used on metals for the same purpose.
Natural Resins

Galvanized Iron
Galvanized iron is essentially iron that’s been coated with a protective zinc layer on the
outside.

What Zinc can Do?
•The zinc coating, when intact, prevents corrosive substances from reaching the underlying steel
or iron.
•It acts as a sacrificial anode, which is the main component of a galvanic cathodic protection
(CP) system used to protect buried or submerged metal from corrosion.
•The zinc protects its base metal by corroding before iron.
•Awnings Industrial walkways
•Balconies Ladders
•Building frames Staircases
•Ductwork Street Furniture
•Handrails Support Beams
•Fences Verandas
Electronics: Computer casings and precision instruments are made with zinc coating because it’s moisture-
and rust-resistant.
Nails, nuts, and bolts: Unfortunately, the hot-dip coating process provides too much fill in the threads of
nuts and bolts that are ⅜-inches or smaller, which can reduce the strength.

Properties of steel (MS):-
1. It's carbon content varies from 0.1% to 0.3%
2. It has fibrous structure and its surface has
bright dark bluish colour
3. It is tough and elastic
4. It is malleable and ductile
5. It cannot resist corrosion.
6. It can withstand sudden shocks
7. It can be magnetized permanently
8. Its melting point is 14000 C
9. It is equally strong in tension and compression
Steel is an alloy of iron with typically a few tenths of a percent of carbon to improve its strength
and fracture resistance compared to iron. Many other elements may be present or added.
Stainless steels that are corrosion- and oxidation-resistant need typically an additional 11%
chromium.
Steel

Classification of steel:-
1) Classification based on carbon content:
a) Low carbon or Mild steel – 250 N/mm2
b) Medium carbon steel
c) High carbon steel – HYSD Bars
2) Based on Purposes:
a) Ordinary structural
b) Quality structural steel
c) Tool Steels
HYSD – High Yeild Strengthen Deformation Bars
415 – 550 N/mm2

Uses of steel (MS):-
1. It is used for making bars and rods which are used in Reinforced work.
2. For making rolled steel sections like angles, channels, T-sections, I-sections.
3. For making bolts, rivets, sheet piles, etc.
4. For making home appliances.
5. It is also used for making tubes.
6. It is used for making Towers and industrial buildings.

Aluminium
Aluminium is the world’s most abundant metal and is the third most common element
comprising 8% of the earth’s crust. The versatility of aluminium makes it the most widely used
metal after steel.

Physical Properties of Aluminium
Density of Aluminium
Aluminium has a density around one third that of steel or copper making it one of the lightest
commercially available metals.
Strength of Aluminium
Pure aluminium doesn’t have a high tensile strength. However, the addition of alloying elements like
manganese, silicon, copper and magnesium can increase the strength properties of aluminium and
produce an alloy with properties tailored to particular applications.
Aluminium is well suited to cold environments. It has the advantage over steel in that its’ tensile
strength increases with decreasing temperature while retaining its toughness. Steel on the other
hand becomes brittle at low temperatures.
Corrosion Resistance of Aluminium
When exposed to air, a layer of aluminium oxide forms almost instantaneously on the surface of
aluminium. This layer has excellent resistance to corrosion. It is fairly resistant to most acids but
less resistant to alkalis.

Thermal Conductivity of Aluminium
The thermal conductivity of aluminium is about three times greater than that of steel. This makes
aluminium an important material for both cooling and heating applications such as heat-
exchangers. Combined with it being non-toxic this property means aluminium is used extensively
in cooking utensils and kitchenware.
Electrical Conductivity of Aluminium
Along with copper, aluminium has an electrical conductivity high enough for use as an electrical
conductor. Although the conductivity of the commonly used conducting alloy (1350) is only around
62% of annealed copper, it is only one third the weight and can therefore conduct twice as much
electricity when compared with copper of the same weight.

Reflectivity of Aluminium
From UV to infra-red, aluminium is an excellent reflector of radiant energy. Visible light reflectivity
of around 80% means it is widely used in light fixtures. The same properties of reflectivity
makes aluminium ideal as an insulating material to protect against the sun’s rays in summer, while
insulating against heat loss in winter.

Applications
1. Long-span roof systems in which live loads are small compared with dead loads, as in the
case of reticular space structures and geodetic domes covering large span areas, like halls and
auditoriums.
2. Structures located in inaccessible places far from the fabrication shop, for which transport
economy and ease of erection are of extreme importance, like for instance electrical
transmission towers, which can be carried by helicopter.
3. Structures situated in corrosive or humid environments such as swimming pool roofs, river
bridges, hydraulic structures and offshore super-structures.
4. Structures having moving parts, such as sewage plant crane bridges and moving bridges,
where lightness means economy of power under service.
5. Structures for special purposes, for which maintenance operations are particularly difficult
and must be limited, as in case of masts, lighting towers, antennas towers, sign motorway
portals, and so on.

Aluminium Cables
Aluminium Cables in Transmission Towers
Aluminium Roofing sheets
Aluminium Window Frames

• Glass is a hard substance which may be transparent or translucent and brittle.
• The fusion process is used to manufacture the glasses.
• In this process, sand is fused with lime, soda, and some other admixtures and then cooled
rapidly.
• Glasses used in construction and architectural purposes in engineering
Glass

Components of Glass
• Silica is the main constituent of glass.
• It is to be added with sodium potassium carbonate to bring down melting point.
• To make it durable lime or lead oxide is also added.
• Manganese oxide is added to nullify the adverse effects of unwanted
iron present in the impure silica.
• The raw materials are ground and sieved.
• They are mixed in specific proportion and melted in furnace. Then glass items are
manufactured by blowing, flat drawing, rolling and pressing.

Important Properties of Glass
1. It absorbs, refracts or transmits light. It can be made
transparent or translucent.
2. It can take excellent polish.
3. It is an excellent electrical insulator.
4. It is strong and brittle.
5. It can be blown, drawn or pressed.
6. It is not affected by atmosphere.
7. It has excellent resistance to chemicals.
8. It is available in various beautiful colours.
9. With the advancement in technology, it is possible
to make glass lighter than cork or stronger than
steel.
10. Glass panes can be cleaned easily.

Types of Glass and their Uses
1. Soda-lime glass
2. Potash lime glass
3. Potash lead glass
4. Common glass and
5. Special glasses.

1. Float Glass / Soda-lime glass
• Float glass manufactured from sodium silicate and calcium
silicate so, it is also called as soda-lime glass.
• It is clear and flat, so it causes glare.
• Thickness of the float glass is available from 2mm to
20mm, and its weight range from 6 to 36 kg/m2.
• The application of float glass includes shop fronts, public
places, etc.
2. Shatterproof Glass
• Shatterproof glass is used for windows, skylights, floors, etc.
• Some type of plastic polyvinyl butyral is added in its making
process.
• So, it cannot form sharp-edged pieces when it breaks

3. Laminated Glass
• Laminated glass is the combination of layers of ordinary
glass. So, it has more weight than a normal glass. It has
more thickness and is UV proof and soundproof. These
are used for aquariums, bridges, etc.
4. Extra Clean Glass
• Extra clean glass has two unique properties,
photocatalytic and hydrophilic. Because of these
properties, it acts as stain proof and gives a beautiful
appearance. Maintenance is also easy.
5. Chromatic Glass
• Chromatic glass is used in ICU’s, meeting rooms etc. it
can control the transparent efficiency of glass and
protects the interior from daylight.

6. Tinted Glass
• Tinted glass is nothing but colored glass. A
color producing ingredients is mixed to the
normal glass mix to produce colored glass
which does not affect other properties of glass.
7. Toughened Glass
• Toughened glass is a durable glass that has low
visibility.
• It is available in all thicknesses, and when it is
broken it forms small granular chunks that are
dangerous.
• This is also called as tempered glass. This type
of glass is used for fire-resistant doors, mobile
screen protectors, etc.

8. Glass Blocks: Glass block or glass bricks are manufactured from
two different halves. They are pressed and annealed together while
melting process of glass.
• These are used as architectural purpose in the construction of walls,
skylights etc. They provide aesthetic appearance when light is passed
through it.
9. Glass Wool: Glass wool is made of fibers of glass and acts as an
insulating filler. It is fire-resistant glass.
10. Insulated Glazed Units: Insulated glazed glass units contains a
glass is separated into two or three layers by air or vacuum.
• They cannot allow heat through it because of air between the layers
and acts as good insulators.
• These are also called as double glazed units.

The term bituminous materials is generally used to denote substances in which bitumen is
present or from which it can be derived. Bitumen is defined as an amorphous, black or dark-
colored, (solid, semi-solid, or viscous) cementitious substance, composed principally of high
molecular weight hydrocarbons, and soluble in carbon disulfide.
Bituminous Materials

Types of Bitumen:
1. Asphalt
2. Macadam
Asphalt
Macadam

Applications:
Agriculture
1. Disinfectants
2. fence proof coat
3. Protection for concrete structures
Buildings:
1. Water Moisture barriers
2. Damp proof coatings
3. Insulating material
4. Canal linings, sealants
Railways:
1. Ballast Treatment
2. Paved ballast
3. Paved crossings

Other Construction activities:
1. Constriction of flexible pavements(Highways)
2. Asphalt blocks
3. crack fillings
4. Soil stabilization
5. Pavements and foot paths

Rubber
Rubber is a naturally occurring material. It is also called as elastomer
Natural Source – Latex
Artificial – Synthetic rubber
Characteristics:
Flexible & Elastic
Not Transparent
Water proof & Repellence
Hard & Strong
Insulate electricity
Acid and Alkaline resistance
Does not conduct heat

ADVANTAGES
Environmental
friendly
Fire and burn
resistance
Strong, Resillent
and rough
Can last longer
with proper
care
Reusable and
Recyclable
Non- Porous
Acts as sound
barrier
Resistance to
burns and Non -
toxic
Very soft to
touch

Fibre Reinforced Plastics
FRP refers to fibre-reinforced plastic (or fibre-reinforced polymer). The word “plastic” or
“polymer” described the binding agent used (such as epoxy resins). FRP is a type of composite
material formed by combining the binding agents with fibre reinforcements to exhibit a desirable
chemical or physical properties.

Arrangement of Fibers in Plastic
The arrangement and orientation of fibre is one of the key feature contributing to the
strength and resistance of the FRP. It indicates how each fibre strand arranged in respect to
the direction of force exerted, as it is crucial to the FRP performance when use for
application like bridge beams, construction framework, parts of airplane and boat, and many
more.

Types of FRP’s based on fibre
•Glass fibre reinforced polymer (GFRP)
•Carbon fibre reinforced polymer (CFRP)
•Aramid fibre reinforced polymer (AFRP)
•Basalt fibre reinforced polymer (BFRP)
•Wood fibre reinforced polymer, or commonly know
as Wood plastic composite (WPC)
•Abestos fibre reinforced polymer
•Quartz fibre reinforced polymer
•Cotton fibre reinforced polymer
•Jute fibre reinforced polymer

Properties:
•High melting points (so they're heat resistant).
•Great hardness and strength.
•Considerable durability (they're long-lasting and hard-wearing).
•Low electrical and thermal conductivity (they're good insulators).
•Chemical inertness (they're unreactive with other chemicals).
Ceramic Materials
A ceramic is any of the various hard, brittle, heat-resistant and corrosion-resistant materials
made by shaping and then firing a nonmetallic mineral, such as clay, at a high
temperature. Common examples are earthenware, porcelain, and brick.

Why do we prefer Ceramic over other materials?
You can bend metals because the
atoms inside them can slide past one
another fairly easily
In a ceramic, the atoms are tightly bonded. If you
apply too much force, the only thing a ceramic can
do is break apart: the energy has nowhere else to
go
In metals, there are free electrons (blue) to carry
heat and electricity. That's why metals are good
conductors
In a ceramic, the electrons are all "busy" binding
atoms together and there are none spare for
carrying electricity and heat. That's why ceramics
tend to be good insulators

Ceramic Products:
1. Clay Tiles
2. Terra – cotta
3. Earthenware
4. Stoneware
5. Porcelain
6. Clay Blocks

Advantages of Terra - Cotta
(i) It is strong and durable material.
(ii) It is available in different colours.
(iii) It is cheaper than ordinary finely dressed stones.
(iv) It is easily cleaned.
(v) It is easily molded in desired shapes.
(vi) It is fire-proof and can therefore be conveniently used with R.C.C. work.
(vii) It is light in weight.
(viii) It is not affected by atmospheric agencies and acids and is capable of withstanding
weathering actions better than most kinds of stone.

Earthenware
The earthen-wares are generally soft and porous. When glazed, the earthen-wares become
impervious to the water and they are not affected by acids or atmospheric agencies.

Porcelain
It is hard, brittle and non-porous. It is prepared from clay, felspar, quartz and
minerals.

Properties of porcelain materials in Electronics

Clay Blocks
The blocks are usually of section 300 mm X 200 mm and the thickness of hollow blocks varies
from 50 mm to 150 mm. The thickness, in case of solid block, is about 40 mm. The blocks are
provided with grooves on top, bottom and sides.

Asbestos is a naturally occurring fibrous silicate mineral. There are six types, all of which are
composed of long and thin fibrous crystals, each fibre being composed of many microscopic
"fibrils" that can be released into the atmosphere by abrasion and other processes. Asbestos is
an excellent electrical insulator and is highly heat-resistant,
Asbestos

•Asbestos was a good insulator. Both for buildings and for hot water pipes and boilers.
•Asbestos was known for its heat resistance. It was used for fireproofing buildings
and chimneys.
•It was mixed with cement. This created heat resistant siding and pipes that were
stronger.
•It was a strengthening agent. Found both in vinyl and drywall (also for heat
resistance).
•Asbestos had sound-dampening qualities. This made it common in ceiling
tiles and popcorn ceilings.
Applications:

Timber.pptx

Recommandé

Recommandé

Contenu connexe

Similaire à Timber.pptx

Similaire à Timber.pptx (20)

Dernier

Dernier (20)

Timber.pptx