202 CIVE Construction Materials
Materials Science & Engineering
Materials: does not refer to all matter in the universe
All matter: physical sciences, life sciences, astronomy,
zoology, etc
Inanimate objects: excludes life sciences
Even this definition is too broad for the engineer
There is a large number of materials useful to mankind - food,
medicine, explosives, chemicals, water, steel, plastics,
concrete, etc
However, only a few qualify as engineering materials
CIVE 202 Construction Materials
Materials Science & Engineering
Engineering Materials are defined as that part of the
inanimate matter which is useful to the engineer in the
practice of his profession
In fact, engineering materials constitute the backbone of
modern civilization
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They are used in one form or another in every sphere of
human activity
Materials can be solid (i.e. steel, concrete), liquid (i.e. water,
acid), or gaseous (i.e. oxygen, carbon dioxide)
CIVE 202 Construction Materials
Materials Science & Engineering
Materials Science refers to the knowledge of physical
sciences arranged as general truth and principle, in
particular physics and chemistry
This is confined to solids in materials science
Thus, materials science is related to solid state physics and
solid state chemistry
The word engineering indicates that the engineering
usefulness or applicability of the material under study is
always kept in mind, irrespective of whether the basic laws of
science can be rigorously applied or not
CIVE 202 Construction Materials
Materials Science & Engineering
Engineering materials can be classified in four broad groups
according to their nature:
1. Metals and Alloys
Metals: characteristic appearance
Capable of changing their shape permanently
Good thermal and electrical conductivity
Reflectivity of light
Alloys: combination of more than one metal
Examples: iron, steel, aluminum, copper, silver, gold,
brass, bronze, manganese, lead, titanium
CIVE 202 Construction Materials
Materials Science & Engineering
2. Ceramics and Glasses
Made from a combination of elements from both the
metals and nonmetals portions of the periodic table
Nonmetallic inorganic substances
Brittle
Good thermal and electrical insulating properties
Examples: bricks, tiles, silica, soda-lime-glass, ferrites
and garnets, graphite,
CIVE 202 Construction Materials
Materials Science & Engineering
3. Organic Polymers
Composed of large number of molecules, joined together
in a chain-like fashion
Majority of engineering polymers are based on
hydrocarbons (molecules that consist of hydrogen and
carbon atoms in various structural arrangements)
Polymeric engineering materials consist of a large
number of synthetic plastics in addition to many natural
polymers such as wood and rubber
CIVE 202 Construction Materials
Materials Science & Engineering
Relatively inert and light
High degree of plasticity (deformability)
Good compatibility with human tissue
Resist atmospheric and other types of corrosion
Resistance to electrical current
Examples: PVA, PVC, polyethylene, epoxy, vinyl ester,
nylon, cotton, leather, aramid
CIVE 202 Construction Materials
Materials Science & Engineering
4. Composites
Combinations of other materials
This class of engineering materials illustrates that
although many dissimilarities may exist between
different materials, they frequently can be utilized in
conjunction to produce a material with unique properties
and behaviour
and behaviour
Composites have rapidly become a separate,
recognized class of engineering materials
Examples: concrete, fibre reinforced polymers (GFRP)
CIVE 202 Construction Materials
Classification
Materials can also be classified according to their major areas
can also be classified according to their major areas
of implementation:
A. Structural
Objects without moving parts
Examples: bridges, dams, steel melting furnaces,
nuclear containment facilities
B. Machines
Involve major parts
Examples: lathes, jet engines, electric motors,
generators
CIVE 202 Construction Materials
Classification
C. Devices
Engineering innovations
Examples: transistors, photoelectric cells, ceramic
magnets, lasers
In each of these applications, materials from one or more of
the three classes are used
Metals and alloys, ceramics and glasses, and polymers are
all engineering materials that have applications in structures,
machines and devices
CIVE 202 Construction Materials
Classification
In materials science, the mere knowledge of the various types
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of engineering materials is not enough
The engineer must know the properties and behavioural
characteristics of the different products manufactured and
the underlying principles governing the engineering
requirements of the various materials
The engineer must be able to evaluate the various material
characteristics and properties
CIVE 202 Construction Materials
Engineering Requirements of Materials
These properties are classified as:
properties are classified as:
Physical: shape, size, finish, color, specific gravity, density,
porosity, structure
Mechanical: strength, stiffness, elasticity, plasticity, ductility,
creep, brittleness, hardness, toughness, resilience, impact
resistance, fatigue behaviour
Thermal: specific heat, heat of transformation, thermal
capacity, thermal expansion, heat transfer and thermal
conductivity, thermal stresses, thermal fatigue, thermal shock
capacity, latent heat of fusion
CIVE 202 Construction Materials
Engineering Requirements of Materials
Electrical: resistivity, conductivity, relative capacity or
dielectric constant, dielectric strength, semi-conductivity,
superconductivity, corrosion resistance*
Chemical: corrosion resistance*, atomic weight, valency,
molecular weight, acidity, alkalinity, atomic number
Magnetic: hysteresis, reductivity, retentivity, susceptibility,
residual inductance, saturation value
CIVE 202 Construction Materials
Engineering Requirements of Materials
Optical: color, lustre, diffraction, fluorescence, reflectivity,
luminescence
Technological: hardness, weldability, machinability,
formability, castability