Zamboanga Peninsula Polytechnic State
University
College of Engineering and Technology
Civil Engineering Department
Construction Materials and
Testing (CE 134)
Lecture 1
Materials Engineering
Concept
Prepared/ Authored by:
Engr. ULMEN RIFF L. CIRCULADO, DoE
Second Semester 2022-2023
1
CONSTRUCTION
MATERIALS
AND TESTING
2
MATERIALS ENGINEER
are responsible for the selection,
specification, and quality control
of materials to be used in a job.
These materials must meet
certain classes of criteria or
materials properties.
3
These classes of criteria include :




Economic Factors
Mechanical Properties
Nonmechanical Properties
Production/construction
considerations
 Aesthetic properties
 Sustainable Design
4
Materials most frequently used
include : Aggregate
5
Materials most frequently used
include : Cement
6
Materials most frequently used
include : Cement
7
Materials most frequently used
include : Concrete
8
Materials most frequently used
include : Concrete
9
Materials most frequently used
include : Concrete
10
Materials most frequently used
include : Concrete
11
Materials most frequently used
include : Concrete
12
Materials most frequently used
include : Concrete
13
Materials most frequently used
include : Concrete
14
Materials most frequently used
include : Concrete
15
Materials most frequently used
include : Steel
16
Materials most frequently used
include : Steel
17
Materials most frequently used
include : Steel
18
Materials most frequently used
include : Steel
19
Materials most frequently used
include : Steel
20
Materials most frequently used
include : Steel
21
Materials most frequently used
include : Steel
22
Materials most frequently used
include : Steel
23
Materials most frequently used
include : Wood
24
Materials most frequently used
include : Wood
25
Materials most frequently used
include : Asphalt
26
Materials most frequently used
include : Asphalt
27
Materials most frequently used
include : Asphalt
28
Recent advances in the technology
of civil engineering materials have
resulted in the development of
better quality, more economical,
and safer materials. These
materials are commonly referred
to as high-performance materials.
29
New materials such as polymers,
adhesives, composites, geotextiles,
coatings, cold-formed metals, and
various synthetic products are
competing with traditional civil
engineering materials.
30
In addition, improvements have
been made to existing materials
by changing their molecular
structures or including additives
to improve quality, economy,
and performance.
31
For example,
 Superplasticizers in the concrete
 Joints made of elastomeric
 Lightweight synthetic aggregates
 Polymers mixed with asphalt
 Fiber-reinforced concrete
32
1. ECONOMIC FACTORS
■
■
■
■
■
■
Availability of raw materials
Cost of raw materials
Manufacturing costs
Transportation
Placing
Maintenance
33
The type of material selected
for a job can greatly affect
the ease of construction and
the construction costs and
time.
34
2. MECHANICAL PROPERTIES
The mechanical behavior of materials
is the response of the material to
external loads. All materials deform in
response to loads; however, the
specific response of a material
depends on its properties, the
magnitude and type of load, and the
geometry of the element.
35
a.) LOADING CONDITION
One of the considerations in the
design of a project is the type of
loading the structure will be
subjected to during its design life.
The two basic types of loads are
static and dynamic.
36
b.) STRESS-STAIN RELATIONS
Materials deform in response to
loads or forces. The amount of
deformation is proportional to
the properties of the material
and its dimensions.
37
b.) STRESS-STAIN RELATIONS
Dividing the force by the cross
sectional area of the specimen
normalizes the effect of the
loaded area.
38
b.) STRESS-STAIN RELATIONS
The force per unit area is defined
as the STRESS in the specimen.
Dividing the deformation by the
original length is defined as
STRAIN of the specimen
39
Typical uniaxial stress–strain diagrams for
GLASS AND CHALK
40
Typical uniaxial stress–strain diagrams for
STEEL
41
Typical uniaxial stress–strain diagrams for
ALUMINUM ALLOYS
42
Typical uniaxial stress–strain diagrams for
CONCRETE
43
Typical uniaxial stress–strain diagrams for
RUBBER
44
c.) ELASTIC BEHAVIOR
If a material exhibits true elastic
behavior, it must have an
instantaneous response to load,
and the material must return to
its original shape when the load
is removed.
45
For a homogeneous, isotropic, and
linear
elastic
material,
the
proportional constant between
normal stress and normal strain of
an axially loaded member is the
modulus of elasticity or Young’s
modulus .
46
In the axial tension test, as the material is
elongated, there is a reduction of the cross
section in the lateral direction. In the axial
compression test, the opposite is true.
The ratio of the lateral strain, to
the axial strain, is Poisson’s ratio.
47
If a homogeneous, isotropic cubical element
with linear elastic response is subjected to
normal stresses and in the three orthogonal
directions the normal strains and can be
computed by the generalized Hooke’s law,
48
49
Sample Problem
A cube made of an alloy with
dimensions of is placed into a pressure
chamber and subjected to a pressure
of 90 MPa. If the modulus of elasticity
of the alloy is 100 GPa and Poisson’s
ratio is 0.28, what will be the length of
each side of the cube, assuming that
the material remains within the elastic
region?
50
Solution:
51
Solution:
52
Linear Elastic Behaviour
53
Nonlinear Elastic Behaviour
54
Several factors affect the
modulus, such as curing
level and proportions of
components of concrete or
the direction of loading
relative to the grain of
wood.
55
d.) ELASTOPLASTIC BEHAVIOR
For some materials, as the stress
applied on the specimen is
increased, the strain will
proportionally increase up to a
point; after this point the strain
will increase with little additional
stress.
56
In this case, the material
exhibits linear elastic behavior
followed by plastic response.
The stress level at which the
behavior changes from elastic
to plastic is the elastic limit.
57
Plastic
behavior
indicates
permanent deformation of the
specimen so that it does not
return to its original shape
when the load is removed.
58
Stress–strain behavior of plastic materials
59
elastic–perfectly plastic
60
elasto–plastic with strain hardening
61
In elastoplastic response the first
portion is an elastic response
followed by a combined elastic
and plastic response.
The stress required to cause plastic
deformation actually increases.
This process is called strain
hardening or work hardening.
62
Sample Problem
An elastoplastic material with strain
hardening has the stress–strain relation
shown below. The modulus of elasticity is
6 psi6 yield strength is 70 ksi, and the
25
x
10
25 x 10 psi yield
slope
of the
strain-hardening
portion of the
strength
is 70
ksi, and
6 psi .
stress–strain
diagram
is
3
x
10
the slope of the strainhardening portion of the
stress–strain diagram is
3 x 106 psi .
63
a. Calculate the strain that corresponds to
a stress of 80 ksi.
Solution:
64
b. If the 80-ksi stress is removed, calculate
the permanent strain.
Solution:
65
Materials that do not undergo
plastic deformation prior to
failure, such as concrete, are said
to be brittle, whereas materials
that display appreciable plastic
deformation, such as mild steel,
are ductile.
66
Three concepts of the stress–strain
behavior of elastoplastic materials.
67
Offset Method
68
Extension Method
69
e.) VISCOELASTIC BEHAVIOR
The previous discussion assumed
that the strain was an immediate
response to stress. This is an
assumption for elastic and
elastoplastic materials. However,
no material has this property
under all conditions.
70
In some cases, materials exhibit
both viscous and elastic
responses, which are known as
viscoelastic.
Time-Dependent Response
Viscoelastic materials have a
delayed response to load
application.
71
Load-deformation response of a
viscoelastic material.
72
There are several mechanisms
associated with time-dependent
deformation, such as creep and
viscous flow.
73
Creep is generally associated
with long-term deformations
and can occur in metals,
ionic and covalent crystals,
and amorphous materials.
74
Behavior of time-dependent materials: creep
75
Viscous flow is associated
only
with
amorphous
materials and can occur
under short-term load
duration.
76
Another
phenomenon
typical of time-dependent
materials is relaxation, or
dissipation of stresses with
time
78
Behavior of time-dependent materials: relaxation
79
e.) TEMPERATURE AND TIME EFFECT
The mechanical behavior of
all materials is affected by
temperature. Some
materials, however, are more
susceptible to temperature
than others.
80
Ferrous metals, including steel,
demonstrate a change from
ductile to brittle behavior as the
temperature drops below the
transition temperature. This
change from ductile to brittle
behavior greatly reduces the
toughness of the material.
81
Fracture toughness of steel under impact testing
82
In addition viscoelastic materials,
are affected by the load
duration. The longer the load is
applied, the larger is the amount
of deformation or creep.
Increasing the load duration and
increasing the temperature cause
similar material responses.
83
Viscoelastic materials also
affected by the rate of load
application. If the load is
applied at a fast rate, the
material is stiffer than if the
load is applied at a slow rate.
84
f.) WORK AND ENERGY
The area under a force
displacement curve is the
work done on the specimen.
85
%
f.) WORK AND ENERGY
The area under the stress–
strain diagram equals the
work per unit volume of
material required to deform
or fracture the material.
86
The area under the elastic portion
of the stress-strain curve is the
modulus of resilience
87
The amount of energy required to
fracture a specimen is a measure
of the toughness of the material
88
High-strength and high-toughness materials
89
g.) FAILURE AND SAFETY
Failure of a structure can
take several modes,
including, fracture, fatigue,
general yielding, buckling,
and excessive deformation
90
Fracture
 When the static stress
reaches the strength of the
 Due to excessive plastic
deformation.
91
Repeated stresses can cause
a material to fail or fatigue
As the stress level decreases,
the number of applications
before failure increases.
92
General yielding
This failure happens in
ductile materials, and it
spreads throughout the
whole structure, which
results in a total collapse.
93
Long and slender members
subjected to axial compression
may fail due to buckling.
94
Excessive deformation
(elastic or plastic) could be
defined as failure, depending
on the function of the
member
95
To minimize the chance of
failure,
structures
are
designed to carry a load
greater than the maximum
anticipated load.
96
The factor of safety (FS) is
defined as the ratio of the
stress at failure to the
allowable stress for design
(maximum anticipated stress):
97
3.NON MECHANICAL PROPERTIES
Nonmechanical properties refer
to characteristics of the material,
other than load response, that
affect selection, use, and
performance.
98
a.) DENSITY AND UNIT WEIGHT
There are three general
terms used to describe the
mass, weight, and volume
relationship of materials.
Density is the mass per unit
volume of material.
99
Unit weight is the weight
per unit volume of material.
100
Specific gravity is the ratio of
the mass of a substance
relative to the mass of an
equal volume of water at a
specified temperature.
101
Specific gravity is equivalent
to the density of a material
divided by the density of
water.
The density of water is 1
or 62.4 lb/ft3 in at 4°C.
3
Mg/m
102
For solid materials, the unit
weight, density, and specific
gravity
have
definite
numerical values.
103
For other materials, voids
in the materials require
definitions for a variety of
densities and specific
gravities.
104
The bulk volume aggregates will occupy
depends on the compaction state of the
material.
Definitions of volume used for determining
density: loose
105
The bulk volume aggregates will occupy
depends on the compaction state of the
material.
Definitions of volume used for determining
density: compacted
106
The density of the material will change
depending on how the volume of
individual particles is measured.
Definitions of volume used for determining
density: total particle volume
107
The density of the material will change
depending on how the volume of
individual particles is measured.
Definitions of volume used for determining
density: volume not accessible to water
108
b.) THERMAL EXPANSION
Materials expand as
temperature increases
and contract as
temperature falls.
110
The amount of expansion per
unit length due to one unit of
temperature increase is a
material constant and is
expressed as the coefficient
of thermal expansion
111
112
Structures are composed of
many materials that are
bound together.
If the coefficients of thermal
expansion are different, the
materials will strain at
different rates.
113
Stresses can also be
developed as a result of a
thermal gradient in the
structure.
114
Materials expand as
temperature increases
and contract as
temperature falls.
115
Sample Problem
A steel bar with a length of 3 m, diameter
of 25 mm, modulus of elasticity of 207
GPa, and linear coefficient of thermal
expansion of 0.000009 m/m/°C is fixed at
both ends when the ambient temperature
is 40°C. If the ambient temperature is
decreased to 15°C, what internal stress
will develop due to this temperature
change? Is this stress tension or
compression? Why?
116
If the bar was fixed at one end and free at the other end,
the bar would have contracted and no stresses would
have developed. In that case, the change in length can
be calculated
Solution:
117
Solution:
118
Solution:
The stress will be tension; in effect, the length of the bar
at 15°C without restraint would be 2.999325 m and the
stress would be zero. Restraining the bar into a longer
condition requires a tensile force.
119
c.) SURFACE CHARACTERISTICS
Corrosion. A process in which
there is a loss of material,
either by dissolution or by the
formation of nonmetallic
scale or film.
120
Degradation. Breakdown of
compound, including the
effects of solvent and
ultraviolet radiation on the
material.
121
The selection of a material
should consider both how
the material will react with
the environment and the
cost of preventing the
resulting degradation.
122
Abrasion and Wear Resistance.
The process of wearing away by
friction.
Since most structures in civil
engineering are static, abrasion
or wear resistance is of less
importance than in other fields
123
Surface Texture.
The surface texture of some
materials and structures is of
importance to civil engineers.
Smooth texture of aggregate
particles is needed in portland
cement concrete to improve
workability during mixing and
placing.
124
Rough texture of aggregate
particles is needed in asphalt
concrete mixtures to provide a
stable pavement layer that
resists deformation under the
action of load.
125
Also, surface texture is needed
in the pavement surface to
provide
adequate
friction
resistance and prevent skidding
of vehicles when the pavement
is wet.
126
4. PRODUCTION & CONSTRUCTION
Production considerations
include the availability of
the material and the ability
to fabricate the material
into the desired shapes and
required specifications.
127
Construction considerations
address all the factors that
relate to the ability to
fabricate and erect the
structure on site.
128
5. AESTHETIC CHARACTERISTIC
The aesthetic characteristics of
a material refer to the
appearance of the material.
Generally, these characteristics
are the responsibility of the
architect.
129
However, the civil engineer is
responsible for working with
the architect to ensure that the
aesthetic characteristics of the
facility are compatible with the
structural requirements.
130
Civil engineers should
understand that there are
many factors beyond the
technical needs that must be
considered when selecting
materials and
designing public projects.
131
6. SUSTAINABLE DESIGN
Sustainable design is the
philosophy
of
designing
physical objects, the built
environment and services to
comply with the principles of
economic,
social,
and
ecological sustainability.
132
7. MATERIAL VARIABILITY
When materials from a
particular lot are tested, the
observed variability is the
cumulative effect of three types
of variance:
1. The inherent variability
of the material
133
2. Variance caused by the
sampling method
3. Variance associated with
the way the tests are
conducted.
134
The goal of a sampling and
testing program is to
minimize sampling and
testing variance so the true
statistical features of the
material
can be identified.
135
The concepts of precision and
accuracy are fundamental to the
understanding of variability.
Precision refers to the variability
of repeat measurements under
carefully controlled conditions.
136
Accuracy is the conformity of
results to the true value or the
absence of bias.
Bias is a tendency of an
estimate to deviate in one
direction from the true value.
137
a.) SAMPLING
Samples are taken from a
lot or population, since it is
not practical or possible to
test the entire lot. By
testing sufficient samples, it
is possible to estimate the
properties of the entire lot.
138
In order for the samples to be
valid they must be randomly
selected. Random sampling
requires that all elements of
the population have an equal
chance for selection and
must be representative of
the entire lot.
139
Statistical parameters describe
the material properties. The
mean and the standard
deviation are two commonly
used statistics.
140
The arithmetic mean is simply
the average of test results of
all specimens tested. It is a
measure of the central
tendency of the population.
141
The standard deviation is a
measure of the dispersion
or spread of the results.
142
8. LABORATORY TESTS
Specimens are made of the
material in question and
tested in the laboratory to
measure their response to
the applied forces or to
certain
environmental
conditions.
144
Measurement of parameters
such as time, deformation, or
force are the basic requirements
of laboratory tests.
Some parameters are measured
directly, while others are
measured indirectly by relating
parameters to each other.
145
Each device has a certain
sensitivity, which is the
smallest value that can be
read on the device’s scale.
146
Magnification
can
be
designed into a gauge to
increase its sensitivity, but
wear, friction, noise, drift,
and other factors may
introduce errors that limit
the accuracy and precision.
147
Many standardized test
methods, such as those of
ASTM and AASHTO, state
the sensitivity of the
measuring devices used in a
given experiment.
148