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UNIT 3

Properties of Materials

Materials we can see around us and those used in civil engineering have various
properties. The word “property” can be used in many different ways. We are going
to use it with the meaning of a quality or feature of something.

All the things we can see around us are made of some kind of material or, in most
cases, of a combination of various materials.

A. Match the object with the best possible material it can be made of. There

are a few possibilities for some of the objects.

Object

Material

1. car

a) plastic

2. window

b) wood

3. electrical wire

c) glass

4. bottle

d) silver

5. cutlery

e) concrete

6. telephone

f) metal

7. table

g) copper

8. pre-made building

blocks

We use particular materials to produce certain objects because of their properties.
How do we find out what the properties of some materials are? The answer is very
simple. We can see the materials or touch them; we can try lifting them or applying
force to them. The materials will perform in a certain way. When we touch the
material, we can feel if it is smooth or rough. Some vandals take a nail or other
sharp object and scratch walls or elevator booths to find out if the material they are
made of is soft or hard. We need a crane to lift a concrete block as it is really
heavy, but things we can lift with our hands are obviously light. We use concrete
blocks for building constructions because they are rigid. But car wheels should be
flexible; therefore, we use rubber for their production. We also have to mention
plasticity and elasticity. A rubber band is elastic, and modelling clay is a plastic
material. They behave differently when we apply force to them. We want to see
through windows, so we use glass to make them. Glass is transparent, but brittle,
so it can be easily broken. Glass is not tough at all. Plastics are tough, but they are
usually either translucent or opaque, so we cannot see clearly through objects
made from them. Another important property in the building industry is
combustibility. Materials can be combustible or non-combustible. We can also
say that materials are flammable or non-flammable. Fire-resistant material will not
burn in the process of combustion and that is the reason why fire-resistant doors in
office or residential buildings are made of non-combustible materials. Unfortunately,
most of the materials we have in our households or offices are combustible; in the

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case of a fire, we can hardly save anything but our lives. Other important properties
are corrosion resistance, which means that materials are resistant against rust, and
conductivity, which means that materials are good or poor conductors of electric
current or heat. For building structures it is important to know if the material is
permeable or impermeable, as builders don’t want moisture or water vapour to pass
inside the building.

B. Match the adjectives with their meanings.

1. combustible

a) not easily broken or made weaker

2. transparent

b) hard and can easily break into pieces

3. elastic

c) easy to press or shape, pleasant to touch, not

rough or stiff

4. rough

d) can be shaped into any shape and will keep that

shape

5. rigid

e) clear and thin enough to see things through

6. translucent

f) able to stretch or bend and then return to its original

shape

7. tough

g) stiff, hard, and difficult to bend or move

8. soft

h) clear enough for light to pass through but not

completely clear

9. brittle

i) a surface which is not smooth

10. plastic

j) able to burn easily

C. What are the opposite meanings of these adjectives?

flexible

______________

soft

______________

rough

______________

brittle

______________

transparent

______________

heavy

______________

combustible ______________
permeable ______________

D. Choose the right answers.

1. Why is glass used for windowpanes?

a) Because it is brittle.
b) Because it is transparent.
c) Because it is waterproof.

2. Why do we use chalk to write on a blackboard?

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a) Because it is white.
b) Because it is brittle.
c) Because it is soft.

3. Why do we need a special drill to make holes in a concrete wall?

a) Because concrete is hard.
b) Because concrete is heavy.
c) Because concrete is rigid.

4. What kind of material should a fireproof door be made of?

a) Combustible material.
b) Non-combustible material.
c) Plastic material.

5. Why do builders need cranes to lift concrete panels?

a) Because concrete panels are square in shape.
b) Because concrete panels are rigid.
c) Because concrete panels are heavy.

6. Why will a glass break into pieces when we drop it?

a) Because it is brittle.
b) Because it is smooth.
c) Because it is tough.

7. Why is aluminium used to construct aircraft?

a) Because aluminium is soft.
b) Because aluminium is easy to shape.
c) Because aluminium is light.

E. Choose the correct properties of the following materials

glass:

a) rigid

b) permeable

c) brittle

wood:

a) combustible

b) brittle

c) transparent

lead:

a) light

b) hard

c) heavy

concrete:

a) flexible

b) rigid

c) combustible

chalk:

a) rigid

b) soft

c) flexible

F. You can form nouns from the adjectives that describe the properties of

building materials.

Adjective

Noun

elastic

soft

fragile

transparent

flexible

brittle

rough

plastic

combustible

tough

rigid

strong

thick

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permeable

weak

dense

hard

smooth

G. Make sentences about four properties of materials from this table.

Steel
Concrete
Glass wool
Brick

has the property of

good sound insulation
good thermal insulation
high compressive strength
high tensile strength

This means

it can resist high compressive forces
it can resist high tensile forces
it does not transmit heat easily
it does not transmit sound easily

H. Answer the following questions:

1. Why is glass used for windowpanes?
2. Why is glass wool used in roof structures to keep heat in the attic?
3. Why is some steel covered with a thin layer of zinc?
4. Why is concrete used for the columns of a building structure?
5. Why is steel used in concrete as reinforcement?

I. Complete the sentences with the correct properties:

1. Various coatings are applied to protect iron from chemical reaction. This

means that iron becomes ______________.

2. A wooden house burnt down, but the windows remained undamaged, i.e.,

wood is __________ and glass is ____________.

3. We need a special drill to make a hole in a concrete wall. This means

concrete is ___________.

4. Electric repairmen use leather gloves, because leather is __________.
5. Concrete panels are lifted by a crane, which means that a concrete panel is

_________.

6. Vertical blinds are used in modern offices to prevent sunrays from penetrating

into the room, i.e., blinds are _____________.

J. What are the properties of the following materials?

concrete, wood, rubber, glass, stone, plastics, lead, clay, chalk, sandpaper.

K. What are these materials used for in construction?

Wood
Strengths: cheap, lightweight, moderately strong in compression and tension
Weaknesses: rots, swells and burns easily
Use:

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Plastics

Strengths: flexible, lightweight, long-lasting, strong in compression and tension
Weaknesses: expensive
Use:
Aluminium (with ingredients of magnesium and copper)
Strengths: lightweight, doesn’t rust, strong in compression and tension
Weaknesses: expensive
Use:
Brick
Strengths: cheap, strong in compression
Weaknesses: heavy, weak in tension
Use:
Concrete
Strengths: cheap, fireproof, weatherproof, moulds to any shape, strong in

compression

Weaknesses: Cracks with temperature changes, weak in tension
Use:
Reinforced concrete
Strengths: low cost, fireproof and weatherproof, moulds to any shape, strong in

compression and tension

Weaknesses: can crack as it cools and hardens
Use:
Iron
Strengths: moulds to any shape, strong in compression
Weaknesses: weaker than steel in tension, breaks without warning
Use:
Steel
Strengths: one of the strongest materials used in construction, strong in

compression and tension

Weaknesses: rusts, loses strength in extremely high temperatures
Use:

L. List materials that possess the following properties.

lightweight –
strong in compression –
rusts –
cheap –
fireproof –
strong in compression and tension –
weak in tension –
expensive –
breaks under tension –
swells and rots –
can crack when cool and hard –
cracks with temperature changes –
loses strength in extremely high temperatures –
doesn’t rust –
heavy –

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UNIT 4

Building Materials

What are building materials? They are materials which are used for construction
purposes. The history of building materials extends back to the time when prehistoric
man abandoned his caves and started building shelters. Just about every type of
available material has been used at one time or another for creating various human
homes. Living spaces and their related structures have been created using myriad
materials, from mud to metal, and from plastic to grass.

What we can see around us are various structures, in most cases, blocks of flats or
detached houses that have been built of concrete panels or bricks. We also might
have seen wooden cottages in villages and countryside. But are bricks, concrete and
wood the only building materials currently used for building purposes? What about
countries located in hot climates? There people use cane, palm leaves or brush,
vines and bamboo for building shelters. In tropical areas people build brush
structures which are made entirely from plant parts. However, these materials have
a relatively short life span because they deteriorate rapidly and are highly
combustible. On the contrary, in the Arctic the Inuit used ice for igloos, which are
shelters built of blocks of snow, generally in the form of a dome. Ice blocks have also
been used for ice hotels as a tourist attraction in northern areas that might not
otherwise see many winter tourists.

Apart from extremely hot or extremely cold locations, when we talk about traditional
building materials we can agree that natural materials such as mud, rocks and small
plants are used as the most basic building materials, aside from tents made of
flexible materials such as cloth or leather. People all over the world have used these
three materials together to create homes to suit their local weather conditions. In
general, stone and brush are used as basic structural components in these buildings,
while mud is used to fill in the space between them.

A. Complete the definitions with the highlighted words in the text. Use the

singular form where necessary.

1. A _________ is a rectangular block used for building walls and other

structures.

2. A _________ is a shelter made of cloth and supported with poles and ropes.
3. A _________ is a large hole in the side of a hill or under the ground.
4. ___________ means to become worse.
5. An __________ is a building made of snow or ice.
6. A ___________ is a place where people are protected from bad weather or

from danger.

7. A __________ is a small house, usually in a village or the countryside.
8. __________ is soft and wet earth.

B. Decide if the sentences are true or false. Correct the false ones.

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1. The Inuit build their shelters of mud.
2. Ice hotels are built to be tourist attractions.
3. Building materials like plants are rather vulnerable.
4. Cloth or leather is not used anymore for building human shelters.
5. We can see many structures built of natural materials around us.
6. Mud belongs among traditional building materials.

C. Fill in the gaps with the appropriate words from the text.

Prehistoric man left ___________ and started building ___________. The
structures around us are built of ___________, __________ or __________. In
tropical areas people use__________, ___________, or ___________ to build
their homes. In the Arctic the Inuit build __________. In some other parts of the
world people live in __________, which are made of cloth or leather.
__________, ___________ and _________ ________ are natural building
materials.

D. Choose the correct option.

1. Brush structures are permanent/combustible/uncomfortable.
2. Igloos are structures built of wood/mud/snow.
3. Prehistoric man abandoned his caves/houses/tents.
4. The structures around us are made of cane/concrete blocks/mud.
5. Tents are made of bricks/leaves/leather.
6. Cottages have been built in the countryside/in cities/in suburbs.
7. In tropical areas people traditionally use sand/plants/bricks for building

shelters.

8. There have been very few/ myriad /not many materials used to create

human homes.

Progress in science and technology and the invention of new substances have
significantly influenced the use of building materials. The most widely used building
materials throughout the world are bricks and stone, mortar and concrete, wood,
metal, glass and plastics.

Brick is an artificial stone made by forming clay into rectangular blocks which are
hardened, either by burning in a kiln or sometimes, in warm countries, by sun-drying.
The colour of the finished bricks depends on the mineral content of the bricks and the
temperature at which they are burned. For example, pink bricks are the result of
high iron content; white or yellow bricks have a higher lime content. Most bricks burn
to various shades of red. In the United Kingdom, bricks have been used in
construction for centuries. Until recently, many houses there were built almost
entirely from red bricks. Although they are now built using a mixture of concrete
blocks and other materials, many houses are lined with a layer of bricks for aesthetic
appeal. Besides their use for building structures, bricks bound together by mortar
form pavements or pedestrian precincts and are also used for decorative purposes.

Mortar is a material used in masonry to fill the gaps between blocks in construction.
Mortar is a mixture of sand, a binder such as cement or lime, and water, and is
applied as a paste, which then sets hard.

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The most widely used building material is concrete. In its simplest form it is a mixture
of cement paste and aggregates. The paste, composed of Portland cement and
water, coats the surface of fine and coarse aggregates. Stone chips, gravel or
crushed rock are called coarse aggregates; sand is a fine aggregate, and cement is a
binding material. After mixing, the cement hydrates and hardens into a stone-like
material. Concrete has a high compressive strength, but a rather low tensile
strength; therefore, it is strengthened using steel rods or bars and is then called
reinforced concrete. The strength and properties of concrete depend on various
factors, such as the quality of the binding material and aggregates; the size, grading
and proportioning of the ingredients, the water-cement ratio, the method of mixing
and placing, the site’s condition, the temperature, and the method of curing, i.e.
supplying water to the concrete after casting. Concrete is extensively used in the
construction of buildings, skyscrapers, bridges, dams and other water structures,
road pavements and runways, and other structures.

Besides the above materials, metal, glass and plastic belong among materials that
have been widely used in the construction of buildings. Clear windows have been
used since the invention of glass to cover small openings in a building. Modern glass
“curtain walls” can be used to cover the entire facade of a building.

E. Decide if the sentences are true or false. Correct the false ones.

1. Brick is a natural stone cut into rectangular blocks.
2. Bricks can also be sun-dried.
3. Bricks are always red.
4. Bricks are bound together by mortar.
5. Mortar contains sand.
6. Cement or lime makes mortar set hard.
7. Sand is a binding material in concrete.
8. Concrete has the property of high tensile strength.

F. Find the correct ending for the following sentences.

1. The invention of new substances has significantly influenced

a) the use of new machinery
b) the use of building materials
c) the process of building houses

2. Brick is an artificial stone made by forming

a) concrete
b) mortar
c) clay

3. The colour of finished bricks depends on

a) the mineral content of the bricks
b) the type of kiln they are burnt in
c) the climate they are used in

4. Pink bricks contain higher amounts of

a) lime
b) iron
c) lead

5. Bricks

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a) have been used in construction for centuries
b) were used in construction in the last century
c) have rarely been used

6. Bricks are bound together by

a) cement
b) concrete
c) mortar

7. Bricks can be used for building

a) airport runways
b) water structures
c) pavements

8. Mortar is a mixture of

a) concrete, sand and binder
b) sand, cement and water
c) lime, water and gravel

9. Concrete is a mixture of

a) cement, water and lime
b) cement, water, sand and aggregates
c) fine aggregates, coarse aggregates and water

10. Concrete has the property of

a) high tensile strength
b) high compressive strength
c) both high tensile and compressive strength

Since the invention of Portland cement in the early 1800s, concrete has remained
relatively unchanged. Producers have always tinkered with the mix to find the right
proportions of concrete’s basic ingredients, but the formula has never varied much.
However, the manufacturing of Portland cement is responsible for about 5 percent of
human-caused emissions of carbon dioxide, which is extremely unfriendly
environmentally. In making concrete Portland cement and water form a paste in
which a series of reactions occur that harden the paste and lock the aggregates
within it. These reactions use up water and produce heat. Therefore, curing is
important. The strengthening process can continue for years, but most of it occurs in
the first few days and weeks. Some researchers want to eliminate Portland cement
entirely and replace it with other cements to produce zero-carbon concrete. The
cement industry, particularly in the United States and Europe, has reduced carbon
dioxide emissions through the use of more efficient kilns and processes. There are
companies that have started developing cements and can make concrete that
absorbs carbon dioxide.
Concrete is made and used just about everywhere, with China responsible for half of
the world’s production. Concrete can be modified by adding other materials and
chemicals. Some chemicals make wet concrete flow better into a form’s nooks
without separating; others prevent the cement particles from flocking together, so the
amount of water can be reduced, which means that less cement is needed as well.
Chemicals can be added to slow the reactions to provide more time to work with the
wet concrete, and other can speed the reactions up if the concrete needs to reach a
certain strength in a short time. Engineers are also paying attention to the internal
structure of the concrete to improve its strength and reduce permeability.

G. Answer the following questions or complete the tasks.

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1. Describe the process of the production of concrete.
2. Why is the production of concrete an environmental problem?
3. Have there been substantial changes in manufacturing concrete?
4. Which substance in concrete is responsible for the emission of carbon

dioxide?

5. How long does the process of strengthening take?
6. What has the cement industry in the US and Europe done to reduce carbon

dioxide emissions?

7. What properties of concrete can be achieved by adding other materials or

chemicals?

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UNIT 5

Natural Building Materials

A. Guess if the sentences are true or false. Then read the text and find out if

you guessed correctly.

1. Modern eco-buildings harness energy using solar panels, wind turbines or

heat pumps.

2. Collecting rainwater is exceptional.
3. It is easier to build with bricks and concrete slabs.
4. Rock structures do not demand hard work.
5. Straw bale houses are highly combustible.
6. Bamboo can be used for bridge constructions.
7. Wood might shrink or expand over time.
8. Earth structures are used by half of the world‘s population.

Construction of residential and office buildings comes at a tremendous expense to
the planet. The use of traditional wood, steel and concrete frames consumes a huge
amount of energy, and cement production results in water and air pollution and
industrial waste that is usually not recycled. It is time to look at new possibilities that
would be in harmony with the environment.

Modern eco-buildings work with the climate. They are super insulated and capture
solar energy, either passively using large glazed areas or actively with solar panels.
Sometimes they even harness wind energy or have ground source heat pumps.
Collecting rainwater is also not exceptional.

One way of constructing environmentally-friendly houses is using natural building
materials that are renewable and locally available as opposed to industrial or man-
made products. Many of them are available throughout the world, so the costs and
pollution associated with transportation goes down.

B.

Answer the following questions.

1. Why is the use of traditional wood, steel and concrete frames in construction a

problem?

2. What are the typical features of modern eco-buildings?
3. Give three reasons that make using natural building materials environmentally

friendly.

It is much easier to build with perfectly shaped bricks or slabs of concrete, but it is
possible to build beautiful houses with locally available stone. The stone can be
mortared with earthen plasters such as sand and clay or lime. Stone walls have very
good thermal mass, which means that they absorb the outside temperature, hold it in
and then radiate it through the home. Stone structures are extremely durable but
very labour intensive.

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Another solution is using straw bales for building houses. They can act as actual
structural building blocks or the fill for insulation in a traditional post-and-beam
structure, where the frame supports the house. After the bales are stacked, the walls
are plastered. Despite what people think, the thick walls provide excellent thermal
and sound insulation. Moreover, since they are tightly packed, they are also fire
resistant.

In Asia and South America houses are frequently made out of wood. Bamboo is an
extremely strong wood which grows very fast; it is also extremely flexible and
durable. Besides being used for construction of scaffolds it is used for highway or
bridge construction in Asia. In Europe and the United States it is popular for
decorative purposes, e.g., bamboo floors. However, bamboo has to be chemically
treated to make it waterproof and insect-resistant.

Cordwood building uses wood that is cut into short lengths, about the size of
firewood, which might otherwise go to waste. The pieces of cordwood are placed into
mortar so that the length of the log determines the length of the wall. The ends of the
log stick out of the mortar on both sides. The mortars that are commonly used
include mixes of cement, lime, clay, sand or sawdust. Cordwood is a natural building
material that offers both good insulation and good thermal mass. The logs provide
insulation that keeps heat in the building, while the mortar provides the ability to store
and release heat into the building. The wood might expand or shrink over time and
crack the mortar, but you can remedy this problem through caulking.

Over one-third of the world's population lives in earthen structures. For many people,
wood is neither affordable nor available, so builders use soil. A rammed earth
house is built by packing down a mixture of soils into a temporary wall form that gives
the mixture its shape. The form is usually wooden, and it must be strong enough to
withstand the compression of the ramming. Ramming can either be done by hand or
by machine, and once it's completed, the forms can be removed, leaving an earthen
wall about 46 cm to 61 cm thick.

Walls can be plastered with stucco or left bare; bare walls usually are internally
stabilized with a small percentage of cement. When properly constructed, rammed
earth walls are extremely durable and provide energy savings because of their
thermal mass.

A building material that is a combination of earth and straw is cob. Cob is a material
used in the form of lumps and provides the opportunity for structural creativity. It
enables curvy shapes and sculptural forms and requires a minimal amount of tools
or construction experience. When the cob dries, it's like concrete, thanks to the
reinforcement of the straw; however, the cob must dry before placing the next layer
of cob lumps. Cob walls cannot be built very high, but when completed, cob walls,
like all earthen methods, provide thermal mass which cools homes in the summer
and warms them in the winter.

One of the oldest forms of building with earth is adobe. It is made by pouring a mix of
clay, sand, water and sometimes straw into a form, most commonly a brick mold. The
forms are left to dry in the sun, and then the forms are removed. This curing process
can take some time, and it requires a continuously dry climate so that the bricks can

38

solidify without getting wet. As the bricks dry, they shrink, so they should be
inspected for cracking. Adjusting the ratio of clay and straw can help prevent
cracking. Adobe bricks are stacked just like conventional masonry and typically
connected with a mud mortar. However, adobe walls are vulnerable to moisture and
usually need large roof overhangs and elevated foundations in wet climates. In
addition, adobe buildings are not a good idea in earthquakeprone areas, although
concrete can be added to the bricks to stabilize them.

The above list of natural building materials and the ways they can be used in the
building industry shows that it is possible to use renewable and recyclable materials
and harm this planet less.

C.

Choose the correct option.

1. Rock structures are

a) durable and easy to build

b) durable but very labour intensive
c) unstable and hard to build

2. Straw bales are

a) fire-resistant
b) highly combustible
c) poor thermal insulators

3. Bamboo

a) grows fast
b) grows slowly
c) is naturally waterproof

4. Cordwood is used

a) as firewood
b) with mortar as a building material
c) as a wooden frame

5. Ramming can be done

a) only by hand
b) only by machine
c) by hand or by machine

6. Cob is a mixture of

a) cement and stone
b) earth and straw
c) earth and wood

7. Adobe bricks are

a) transported to kilns to dry
b) cured by pouring water on them
c) left to dry in the sun

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D. Fill in the following table.

Material

Method of utilization

Properties

Positive

Negative

rocks

straw bales

bamboo

cordwood

rammed earth

cob

adobe

E. Match the opposites.

1. fire-resistant

a) rigid

2. tightly

b) expand

3. flexible

c) permeable

4. waterproof

d) unfinished

5. shrink

e) combustible

6. completed

f) covered

7. bare

g) loosely

Modifiers

Adjectives modify or describe nouns or pronouns, giving more information about
them. They are used to describe colour, material, shape, size, amount, price, quality,
origin, temperature, age, direction, etc. In most technical texts their use is

40

mandatory, giving the noun its real meaning, e.g., solar panel, thermal insulation.
We sometimes use compound adjectives.
A compound adjective is formed when two or more adjectives work together to
modify the same noun. These terms should be hyphenated to avoid confusion or
ambiguity, e.g., long-term, air-conditioned, etc.
In technical writing nouns are often used to modify other nouns and are called
attributive nouns. The modifier often indicates origin or purpose. A fixed expression,
which is made up of more than one word and functions as a noun, is a compound
noun, e.g., a credit card, light bulb, etc.
Modifiers are often hyphenated, but when the meaning is obvious, use of the hyphen
is unnecessary.

F. Find at least 5 examples of adjective-noun expressions and noun + noun

expressions in the text.

G. Fill in each of the blanks to form as many compound adjectives as possible.

__________________ - proof
__________________ - resistant
__________________ - made
__________________ - free
__________________ - intensive