Unit v: building materials

TEXT A

Vocabulary

to consider- принимать во внимание property - свойство

requirement - требование to meet requirements – отвечать требованиям fire-resistant – огнеупорный steel – сталь

to decay – гнить ancient – древний

to harden – твердеть crushed stone - щебень

prestressed - предварительно напряженный reinforced concrete - железобетон

reinforcement– арматура glass reinforced plastics - стеклопластик

polyester resin - полиэфирная смола availability- наличие

hard - твердый, жесткий purpose – цель

concrete – бетон brick - кирпич

clay – глина disadvantage - недостаток

fine – мелкий aggregate - заполнитель

cement – цемент gravel - гравий

rod - стержень, брус fibre - волокно

chemicals – химикаты glass– стекло

coarse- крупный

BUILDING MATERIALS

In order to build a house the civil engineer must consider many important factors: the choice of materials, their physical properties, availability, cost, etc. Materials to be used for structural purposes should meet a number of requirements. In most cases they should be strong, durable and fire-resistant.

Steel, concrete, stone, timber and brick are the most commonly used building materials. Timber is the oldest structural material known to mankind. It is light, cheap and easy to work with. But timber has certain disadvantages: it burns and decays. Timber used for building purposes is divided into two groups: softwoods and hardwoods. Softwoods are chiefly used in construction, while hardwoods are generally used for decorative purposes.

Bricks were known many thousands of years ago. They are molded from clay into the required shape. Bricks are usually rectangular in shape. They are hardened by being fired in a kiln.

Concrete is one of the most important building materials. It is difficult to imagine modern structures without concrete. Concrete is made by mixing together a proportion of fine and coarse aggregates with cement and water. Crushed stone, broken brick and gravel are considered to be coarse aggregates. Sand is the best fine aggregate. Both quarry and river sands are extensively used.

Reinforced concrete is a combination of two of the strongest structural materials available - concrete and steel. There are two kinds of reinforced concrete: with ordinary reinforcement and concrete with prestressed reinforcement. Concrete is reinforced by the incorporation of steel rods.

Plastics and glass reinforced plastics are comparatively new building materials, but they have already found many uses in modern construction. Plastics combine all the best characteristics of building materials with good insulating properties. Plastics are produced
from chemicals. Glass-reinforced plastics are produced from polyester resins reinforced
with glass fibres. Plastics and glass-reinforced plastics are the materials to be used in
modern construction on a large scale.

Exercise I

Answer the questions:

1. What must a civil engineer consider to build a house?

2. What requirements should building materials meet?

3. What are the most commonly used building materials?

4. Into what groups is timber divided?

5. For what purposes are they used?

6. What does concrete consist of?

7. What fine and coarse aggregates do you know?

8 .What components does reinforced concrete include?

9. What is the process of reinforcing ordinary concrete structures?

10 Why have plastics already found use in modern construction?

Exercise II

Give the necessary English equivalents:

1.Materials used in modern construction should (отвечать нескольким требованиям).

2.(Лесоматериал) is light, cheap and easy to work with, but it has certain (недостатки).

3.(Кирпичи) are hardened (обжигом в печи).

4.Building materials should be (прочный, огнеупорный).

5.Concrete is made by mixing cement, sand, gravel and water (в нужных пропорциях).

6.(Ввести стальные стержни в бетон) is to reinforce ordinary concrete structures.

7.Plastics are produced from (химикаты).

8.Sand is the best (мелкий заполнитель).

Exercise III

Translate into English:

1. Для строительства здания необходимы разнообразные строительные материалы.

2.Кирпич, лесоматериалы, бетон, железобетон и пластмассы - это наиболее важные
материалы, применяемые в строительстве.

3.Сталь используется в качестве арматуры в железобетонных конструкциях.

4.Бетон изготовляется путем замешивания в соответствующих пропорциях мелкого и
крупного заполнителей, цемента и воды.

5.Кирпич - это искусственный материал, изготовленный из глины и закаленный
обжигом па солнце или в обжиговой печи.

6.Железобетон состоит из двух прочнейших материалов - бетона и стали. Он широко
применяется для строительства жилых и промышленных зданий.

7.Пластмассы и стеклопластики являются новейшими стройматериалами. Они
обладают хорошими изоляционными свойствами.

TEXT B

Reinforced concrete

Reinforced concrete is a combination of two of the strongest struc­tural materials, concrete and steel.

This term is applied to a construction in which steel bars or heavy steel mesh are properly embedded in concrete. The steel is put in posi­tion and concrete is poured around and over it, then tamped in place so that the steel is completely embedded. When the concrete hardens and sets, the resulting material gains great strength. This new structural concrete came into practical application at the turn of the 19th century. The first results of the tests of the reinforced concrete beams were pub­lished in 1887. Since that time the development of reinforced concrete work has made great progress. And the reasons of this progress are quite evident. Concrete has poor elastic and tension properties, but it is rigid, strong in compression, durable under and above ground and in the presence or absence of air and water, it increases its strength with age, it is fireproof.

Steel has great tensional, compressive and elastic properties, but it is not durable being exposed to moisture, it loses its strength with age, or being subjected to high temperature. So, what is the effect of the ad­dition of steel reinforcement to concrete?

Steel does not undergo shrinkage or drying but concrete does and therefore the steel acts as a restraining medium in a reinforced concrete member. Shrinkage causes tensile stresses in the concrete which are balanced by compressive stresses in the steel. For getting the best from reinforced concrete the following consideration should be kept in mind:

1. For general use the most suitable proportions of cement and ag­gregate are: 1 part cement, 2 parts sand and 4 parts of gravel.

2. Only fresh water free from organic matter should be used for reinforced work. Sea water is not allowed.

3. Homogeneity of the concrete is a very important requirement.
Steel constructions with reinforced concrete have become the most important building materials invented in centuries and they have given modern architecture its peculiar features.

Exercise I

Answer the following questions:

1. Is reinforced concrete a combination of two of the strongest structural materials?

2. What is the process of making reinforced concrete?

3. When did this new structural concrete come into practical application?

4. Since what time has the development of reinforced concrete work made good progress?

5. Can you name the properties of concrete?

6. Will yousay a few words about the properties of steel?

7. Does concrete increase its strength with age? What about steel?

8. Is it true that steel does not undergo shrinkage or drying but concrete does?

9. Shrinkage causes tensile stresses in the concrete, doesn't it?

Exercise II

Make up sentences using the following words:

to combine - combination; strong – strength - to strengthen; hard - to harden - hardness; tension - tensional; compression - compressive; durable - durability; to apply - application; to shrink – shrinkage

Exercise III

What is the English for:

1. применять термин; 2. заливать бетон; 3. набирать прочность; 4.быть опубликованным;

5. увеличивать, уменьшать прочность; 6. подвергаться усадке; 7. вызывать растягивающие усилия; 8. использовать железобетон

Exercise IV

Read and translate the dialogues:

Dialogue 1

A:There's something I want to ask you. May I?

B: Sure, you may! Why not? Go ahead!

A:What is the most important component of concrete?

B: Do you mean to say that you don't know?

A:Honestly, I don’t! Tell me, please!

В: OK, listen. The most important component of concrete is cement.

Dialogue 2

A: May concrete be considered as an artificial conglomerate stone?

В: Certainly, it may! Why not?

A: You know how it's made, don't you?

B:Sure, I do. It's made by uniting cement and water into a paste.

A: What about sand? Isn't sand used?

В: Of course, sand is used! How can you make concrete without sand?

Dialogue 3

A:Concrete has great compressive strength, doesn't it?

В: Quite true, it has enormous compressive strength!

A: Does it have great ability to withstand tension?

B: Tension, you say? It has very little ability to withstand tension.

Dialogue 4

A: Are lime, gypsum and cement widely used in building construction?

B: It goes without saying that they are!

A:For what purpose are they so widely used?

В: They are used for the purpose of binding together masonry units.

A:Masonry units? What kind of masonry units?

B: Don't you know? Masonry units such as stone, bricks and terra cotta.

Dialogue 5

A: What qualities does a brick building possess?

B: A brick building is strong and durable.

A: Do you consider a brick building to be weather resistant too?

В:Naturally, I do! A brick building is weather resistant too.