The document provides an overview of different building materials, their properties, and classifications. It discusses natural materials like stone, wood, and clay as well as synthetic materials like steel, concrete, glass, and plastics. The properties of building materials that are described include density, porosity, strength, durability, and resistance to factors like fire, moisture, and frost.

1. International Burch university Course : Building Construction Technology I
Architecture department Date : xx / xx / xxxx
Sarajevo
LECTURE NO.6
INTRODUCTION TO BUILDING MATERIALS
Building Construction Technology I
Professor : Prof.dr.Nerman Rustempasic
Assistant : M.Sc. Ahmed El Sayed

2. INTRODUCTION
 Any material which is used in construction of residential or
commercial buildings is dubbed as building material.
 The choice of building material depends on :
 the size and nature of building,
 its design,
 intended purposes,
 availability of resources
 location.
 Usually building materials are classified as
 natural
 synthetic materials

3. BRIEF INTRODUCTION TO BUILDING
MATERIALS
Rock :
 Easily, one of the most solid and durable material used in
constructions,
 Rock is a very dense material so it gives a lot of protection
too.
 Dry-stone walls have been built for as long as humans have
put one stone on top of another.
 Mostly Stone buildings can be seen in most major cities,
some civilizations built entirely with stone.
Question : name two draw-backs for stone.

4. Mud and Clay :
 Mud and clay are the most commonly used materials in
residential buildings.
 Buildings made primarily of mud and clay can easily endure
many years.
 Using mud and clay in buildings is a very good option for
warm places,
Question : Why using mud and clay in bulidings is a very good
option for warm places ?
 Soil and especially clay is good thermal mass; it is very good
at keeping temperatures at a constant level.
 Homes built with earth tend to be naturally cool in the summer
heat and warm in cold weather.

5. Wood :
 A natural material for building dwellings for thousands of
years,
 Wood was also used to make Churches in the past.
Question : What is the main problems with wood structures ?
 Wood is an aesthetically pleasing material that never goes out
of trend completely,
 Wood obtained from certain plants is quite durable, however
low quality wood is open to many extremities.
 These days wood is mostly used for making cabinets,
furniture or wardrobes.

6. Metals / Steel :
 Metal is used as structural framework for larger buildings such
as Skyscrapers, or as an external surface covering.
 Steel is a metal alloy whose major component is iron, and is
the usual choice for metal structural building materials.
 It is strong, flexible, and if refined well and/or treated lasts a
long time.
Question : What is metal’s prime enemy ?
 The lower density and better corrosion resistance of
aluminium alloys and tin sometimes overcome their greater
cost.

7. Glass :
 Glassmaking is considered an art form as well as an industrial
process or material.
 Clear windows have been used since the invention of glass to
cover small openings in a building.
Question : What makes glass different from other building materials
?
 Glass is generally made from mixtures of sand and silicates,
in a very hot fire stove called a klin and is very brittle.
 Very often additives are added to the mixture when making to
produce glass with shades of colors or various characteristics.
 The use of glass in architectural buildings has become very
popular in the modern culture.

8. Plastic :
 The term plastics covers a range of synthetic or semi-
synthetic organic condesition or polymerzation products that
can be molded or extruded into objects or films or fibers.
 Plastics vary immensely in heat tolerance, hardness, and
resiliency. Combined with this adaptability,
 Plastic is a light, flexible substance, used mostly for piping in
buildings.
 Their name is derived from the fact that in their semi-liquid
state they are malleable, or have the property of plasticity.

9. Concrete :
 Concrete is made by mixing cement, sand, gravel and water,
while the structures are made using steel bars.
 The most common form of concrete is Portland cement
concrete, which consists of mineral aggregate (generally
gravel and sand), portland cement and water.
 Concrete is another material known for its durability
 It is more convenient to use as far as portability and molding
is concerned.
 For a concrete construction of any size, as concrete has a
rather low tensile strenght, it is generally strengthened using
steel rods or bars (known as rebars).

10. FUNDAMENTAL PROPERTIES OF
BUILDING MATERIALS
 Parametars of state / structural characteristics
 Physical properties
 Mechanical properties

11. Density :
 Ratio of the mass of a substance to its volume, expressed,
for example, in units of grams per cubic centimeter or pounds
per cubic foot.
 The density of a pure substance varies little from sample to
sample and is often considered a characteristic property of
the substance.
 The bulk density of soil depends greatly on the mineral make
up of soil and the degree of compaction.
 Bulk density = mass of soil/core volume
 The bulk density of soil is inversely related to the porosity of
the same soil: the more pore space in a soil the lower the
value for bulk.
 Specific density ( specific mass ) is the mass of apsulutly
dense material. ( 100% solid material ).

12. Porosity :
 Porosity or void fraction is a measure of the void (i.e.,
"empty") spaces in a material, and is a fraction of the volume
of voids over the total volume.
 Effective porosity (also called open porosity) :
Refers to the fraction of the total volume in which fluid flow is
effectively taking place.
 Ineffective porosity (also called closed porosity) :
Refers to the fraction of the total volume in fluids or gases are
present but in which fluid flow can not effectively take place
and includes the closed pores.

14. Hydro-physical properties :
 Hygroscopicity : is the capacity of a product (e.g. cargo,
packaging material) to react to the moisture content of the air
by absorbing or releasing water vapor.
 Water absorption : The amount of water absorbed by a
composite material when immersed in water for a stipulated
period of time.
 Moisture : Water content or moisture content is the quantity of
water contained in a material, such as soil (called soil
moisture), rock, ceramics, fruit, or wood
 Water permeability : The rate of water flow in gallons per day
through a cross section of 1 square foot under a unit hydraulic
gradient, at the prevailing temperature.
 Shrinking and swelling : Swelling soils are soils or soft
bedrock that increase in volume as they get wet and shrink as
they dry out

15. Thermo-technical properties :
 Thermal conductivity : is the property of a material's ability to
conduct heat
Question : Explain ?
 Fire resistance : A fire-resistance rating typically means the
duration for which a passive fire protection system can
withstand a standard fire resistance test.
 Thermal diffusivity : The thermal diffusivity is a measure of the
transient heat flow through a material.
 Specific heat : The specific heat is a measure of the amount
of energy required to change the temperature of a given mass
of material.

16.  Melting point : The melting point is the temperature at which a
material goes from the solid to the liquid state at one
atmosphere.
 Thermal expansion coefficient : The thermal expansion
coefficient is the amount a material will change in dimension
with a change in temperature.
 Thermal shock resistance : Thermal shock resistance is a
measure of how large a change in temperature a material can
withstand without damage. Thermal shock resistance is very
important to most high temperature designs.

17. Viscosity :
 Viscosity is a measure of the resistance of a fluid which is
being deformed by either shear or tensile stress. In everyday
terms (and for fluids only), viscosity is "thickness" or "internal
friction". Thus, water is "thin", having a lower viscosity, while
honey is "thick", having a higher viscosity.
 Viscosity describes a fluid's internal resistance to flow and
may be thought of as a measure of fluid friction.
Question : Why is viscosity important if we are talking about solid
materials ?

18. Frost resistance :
 The ability of building materials in a wet condition to withstand
many cycles of freezing and thawing without disintegrating.
 The basic cause of the disintegration of materials acted upon
by low temperatures is that the water filling the pores of the
material expands when it freezes.
 Frost resistance depends primarily on the structure of the
material: the larger the pores that water can penetrate, the
lower frost resistance will be.
 The frost resistance value is the number of cycles of freezing
and thawing the material can undergo before losing 25
percent of its initial strength or 5 percent of its weight.
Question : How to improve frost resistance ?

19. Acoustic properties :
 The study of sound and sound phenomena led to a scientific
discipline called Acoustics.
 Acoustic absorption is that property of any material that
changes the acoustic energy of sound waves into another
form, often heat, which it to some extent retains, as opposed
to that sound energy that material reflects or conducts.
 The absorptivity of a given material is frequency-dependent
and is affected by size, shape, location and the mounting
method used. Porous insulative materials such as mineral
wool or glass wool are effective sound absorbers.
Question : What about metals ?

20.  The mechanical properties of a material describe how it will
react to physical forces.
 The deformation that takes place is called the STRAIN, while
the force causing the deformation is known as the STRESS.
The strain may be a change in size (length, area or volume),
while the stress may be :
 forces of tension (that tend to increase length),
 compression (that tend to reduce length), or,
 shear (where parallel planes of a body tend to slide over each other.

21.  Stress is measured in units of force per unit area of cross-
section (N.m-2), and is commonly given the symbol σ (greek
"sigma"). Since the dimensions of stress are the same as
those for pressure, stress is frequently measured in pascals.
Strain is a pure number, and is given the symbol ε (greek
"epsilon").
 A material is said to be ELASTIC if, when deformed by an
applied force, it returns to its original shape when the force is
removed.
 Permanent deformation may occur if the stress is too large.
However, many structural materials also present the property
of RIGIDITY, in that they will offer resistance to stress.

22. The relationship between stress and strain in elastic materials
was investigated by Robert Hooke, and led to what is known
as Hooke's law.
"For an elastic material, the strain is directly proportional to the stress.“

23. Definition :
 The point up to which the stress and strain are linearly related
is called the proportional limit.
 The largest stress in the stress strain curve is called the
ultimate stress.
 The stress at the point of rupture is called the fracture or
rupture stress.
 The region of the stress-strain curve in which the material
returns to the undeformed state when applied forces are
removed is called the elastic region.
 The region in which the material deforms permanently is
called the plastic region.
 The point demarcating the elastic from the plastic region is
called the yield point. The stress at yield point is called the
yield stress.

24.  The permanent strain when stresses are zero is called the
plastic strain.
 The off-set yield stress is a stress that would produce a
plastic strain corresponding to the specified off-set strain.
 A material that can undergo large plastic deformation before
fracture is called a ductile material.
 A material that exhibits little or no plastic deformation at failure
is called a brittle material.
 Hardness is the resistance to indentation.
 The raising of the yield point with increasing strain is called
strain hardening.
 The sudden decrease in the area of cross-section after
ultimate stress is called necking.

26. Strenght :
 Strength has several definitions depending on the material
type and application.
 Before choosing a material based on its published or
measured strength it is important to understand the manner in
which strength is defined and how it is measured.
 When designing for strength, material class and mode of
loading are important considerations.
 For metals the most common measure of strength is the yield
strength.
 For most polymers it is more convenient to measure the
failure strength, the stress at the point where the stress strain
curve becomes obviously non-linear.
 Strength, for ceramics however, is more difficult to define.
Failure in ceramics is highly dependent on the mode of
loading.

27. Elastic limit :
 The elastic limit is the highest stress at which all deformation
strains are fully recoverable.
 For most materials and applications this can be considered
the practical limit to the maximum stress a component can
withstand and still function as designed.
 Beyond the elastic limit permanent strains are likely to deform
the material to the point where its function is impaired.

28. Proportional limit :
 The proportional limit is the highest stress at which stress is
linearly proportional to strain.
 This is the same as the elastic limit for most materials.
 Some materials may show a slight deviation from
proportionality while still under recoverable strain. In these
cases the proportional limit is preferred as a maximum stress
level because deformation becomes less predictable above it.

29. Yield Strength :
 The yield strength is the minimum stress which produces
permanent plastic deformation.
 This is perhaps the most common material property reported
for structural materials because of the ease and relative
accuracy of its measurement.
 The yield strength is usually defined at a specific amount of
plastic strain, or offset, which may vary by material and or
specification.
 The offset is the amount that the stress-strain curve deviates
from the linear elastic line. The most common offset for
structural metals is 0.2%.

30. Ultimate Tensile Strength :
 The ultimate tensile strength is an engineering value
calculated by dividing the maximum load on a material
experienced during a tensile test by the initial cross section of
the test sample.
 The ultimate tensile strength helps to provide a good
indication of a material's toughness but is not by itself a useful
design limit.
 Conversely this can be construed as the minimum stress that
is necessary to ensure the failure of a material.

31. True Fracture Strength :
 The true fracture strength is the load at fracture divided by the
cross sectional area of the sample.
 Like the ultimate tensile strength the true fracture strength can
help an engineer to predict the behavior of the material but is
not itself a practical strength limit.

32. Ductility :
 Ductility is a measure of how much deformation or strain a
material can withstand before breaking.
 The most common measure of ductility is the percentage of
change in length of a tensile sample after breaking.
 This is generally reported as % El or percent elongation.

33. Toughness :
 Toughness describes a material's resistance to fracture. It is
often expressed in terms of the amount of energy a material
can absorb before fracture.
 Tough materials can absorb a considerable amount of energy
before fracture while brittle materials absorb very little.
 Neither strong materials such as glass or very ductile
materials such as taffy can absorb large amounts of energy
before failure.
 Toughness is not a single property but rather a combination of
strength and ductility.
 Materials with high yield strength and high ductility have high
toughness.

34. Fatigue ratio :
 The dimensionless fatigue ratio f is the ratio of the stress
required to cause failure after a specific number of cycles to
the yield stress of a material.
 Fatigue tests are generally run through 107 or 108 cycles.
 A high fatigue ratio indicates materials which are more
susceptible to crack growth during cyclic loading.

35. Loss coefficient :
 The loss coefficient is another important material parameter in
cyclic loading. It is the fraction of mechanical energy lost in a
stress strain cycle.
 The loss coefficient for each material is a function of the
frequency of the cycle.
 A high loss coefficient can be desirable for damping vibrations
while a low loss coefficient transmits energy more efficiently.
 The loss coefficient is also an important factor in resisting
fatigue failure. If the loss coefficient is too high, cyclic loading
will dissipate energy into the material leading to fatigue
failure.

36. THANK YOU