Wollo University KIOT
Department of civil Engineering
Classification of Materials
Properties of Materials
Behavior of Materials under Load
Stress-Strain Properties
Introduction
Lime
Gypsum
Portland Cement
Introduction
Classification of stone
Properties of D/t Stones
Production of Stone
Building-Stone Requirements
Tests on Building Stone
DEFINITION AND USE
MORTAR MIXES
PROPERTIES OF
MORTAR
Introduction
Raw Materials
Manufacture of Brick
Brick kilns
Types of Bricks
Tests and classification
Introduction
Concrete Making
Materials
Fresh Concrete
Hardened Concrete
Mix Design
Introduction
Growth of Wood
Classification
Defects in Timber
Seasoning of Wood
Classification of Metals
Ferrous Metals
Nonferrous Metals
Materials that are used for construction of buildings, highways,
bridges, mostly infrastructure.
The most importance materials are
Stones
Woods
Concrete
steel
Brick
Asphalt
Materials that are used for construction purpose can be
broadly classified into Metallic and Non-metallic based
on their metallic nature.
In general, metals can be classified into two major
groups: and
A ferrous metal is one in A non-ferrous metal is one
which the principal element in which the principal
is iron, as in: element is not iron, as in:
These includes:
Based on their physical nature materials can also
be divided as:
Materials can also be classified based on their
mode of production as:
Properties of materials have great
practical significance and a broad
understanding of these properties is
essential.
Properties which relate to materials
generally are:
Density
Heat conductivity
Acoustic permeability
Porosity
* Corrosion resistance
* Combustibility
* Toxicity
* Decay resistance
-resistance of a material to the
action of external
(compressive, tensile, bending, shear, and
torsional strength) and various
external forces (impact and vibratory
loads).
Application of external forces on a solid body in
equilibrium results in:
Internal resisting forces are developed in the body
which balance the externally applied force.
The body is deformed to varying degree.
The intensity of the internal force is called Stress and
the deformation per unit length is called Strain.
Cont’d…
If a body recovers the original form, it is said to be Elastic.
If it fails to recover its original form, it is said to be Plastic.
A perfectly elastic body is one that fully recovers its
original size and shape after the application and removal of
load.
Most engineering materials are in part elastic and in part
plastic.
Stiffness is the measure of the ability of the material to
resist deformation .In other words, a body is said to be stiff
if it sustains large loads without so much deformations.
As the magnitude of the applied load increase the
deformation increases, a point is reached beyond which the
original form is not fully recovered; this point is
of the material.
Mechanical tests are those used to examine the performance
of construction materials under the action of external forces.
Mechanical tests may be classified under the following
headings:-
i. Tension test
ii. Compression test
iii. Shear test
iv. Bending test
v. Torsion test:
i) Static tests: made with gradually increasing load.
ii) Dynamic tests: made with suddenly applied
loads.
III) Wear tests: made to determine resistance to
abrasion and impact.
iv) Long-time tests: made with loads applied for a
long period of time.
v) Fatigue tests: made with fluctuating stresses
repeated a large number of times.
i) Under these test, the specimens
are either crushed or ruptured and made useless at the
end of the test.
ii) These are usually used to
test the strength of members of existing structures
without affecting their performance.
In the standard conventional tension test, a specimen
is subjected to a gradually increasing axial tensile
force P by means of a testing machine.
At various increment of force, the change in length
ΔL of the specimen for an initial length Lo are
measured by the influence of strain.
for a length Lo of the specimen, the stress is uniformly
distributed for all points on each cross section perpendicular
to the line of action of the force.
Where: σ = the tensile stress
P = applied load
A=area of the cross section perpendicular to the line of
action of the applied force.
This uniform stress will produce a uniform
elongation ΔL. The value of the elongation per unit
length (strain) is expressed as:
Where: ε = strain
ΔL= total elongation
Lo =original length of the specimen
The diagram begins with a straight line from the origin
0 to point A,
These stress- strain will be:
( p A0 ) PL0
t = E or E t
( l L0 ) A0 l
E = the slope of the straight line, is called the modulus of
elasticity.
The stress-strain relation is referred to as
Beyond point A, the proportionality
between stress and strain no longer exists;
hence, the stress at A is called the
For low-carbon steels, this limit is in the
range 210 to 350 MPa.
the greatest stress which the material is capable of
withstanding without a deviation from the law of the proportionality.
the greatest stress which a material is capable of withstanding
without a permanent deformation remaining upon release of stress. (point b)
the transition from the elastic range to the plastic
range. ( point b to c)
stress at which there occurs a marked increase in strain without an
increase in stress (only for ductile materials).
c - Upper yield point.
d - Lower yield point.
(young’s modulus): the slope of the initial
linear portion of the stress-strain curve.
Three different methods are employed for materials with curved
stress-strain diagrams.
the slope at the origin of the curve.
E1 = tan1
the slope of the line joining the origin and a
selected point A on the curve. E2 = tan2
the slope of the tangent to the curve at a
selected point B. E3 = tan3
The ratio of transverse contraction
strain to longitudinal extension strain in the direction of stretching
force.
•Resilience: It is the ability of a material to absorb
energy when deformed elastically and return it when
unloaded.
In the plastic range a permanent deformation remains
in the stressed body after complete removal of the
load.
it is the maximum stress a
material can possibly resist just before failure. It may
correspond to the ultimate strength (ultimate stress) or
to the fracture (rupture) strength.
it represents the material ability to
deform in the plastic range.
Cont’d…
Toughness: its ability to absorb energy before fracture (in the
plastic range).
Toughness can be determined by measuring the area (i.e., by
taking the integral) underneath the stress-strain curve , and its
energy of mechanical deformation per unit volume prior to
fracture.
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