The properties of building materials

All building materials should meet several requirements. In most cases, it is important that they should be hard, fire-resistant and easily fastened together. The most commonly used materials are steel, concrete, stone, wood and brick. They differ in hardness, durability and fire-resistance.

Wood is the most ancient structural material. It is light, cheap and easy to work. But wood has certain disadvantages: it burns and decays.

Stone belongs to one of the oldest building materials used by man. Its properties are mechanical strength, compactness, porosity, sound and heat insulation and fire resistance.

Bricks were known many thousands years ago. They are examples of artificial building materials.

Concrete is referred to as one of the most important building materials. Concrete is a mixture of cement, sand, crushed stone and water.

Steel was known in antiquity. The earliest known production of steel is a piece of ironware excavated from an archaeological site in Anatolia and is about 4,000 years old. Steel is an alloy of iron and other elements, including carbon. The following elements are always present in steel: carbon, manganese, phosphorus, sulfur, silicon, and traces of oxygen, nitrogen and aluminum.

Plastics are typically organic polymers of high molecular mass, but they often contain other substances. They are usually synthetic, most commonly derived from petrochemicals, but many are partially natural.

All building materials are divided into three main groups: 1) Main building materials such as rocks and artificial stones, timber and metals. 2) Binding materials such as lime, gypsum and cement. 3) Secondary or auxiliary materials, which are used for interior parts of the buildings.

We use many building materials for bearing structures. Binding materials are used for making artificial stones and for joining different planes. For the interior finish of the building we use secondary materials.

Natural building materials are stone, sand, lime and timber. Cement, clay products and concrete are examples of artificial building materials. (1900)

V. Complete the following sentences according to the content of the text:

1.​ All building materials should be ……………..

2.​ The most widely used building materials are …………

3.​ The oldest structural material is ………………….

4.​ The advantages of wood are …………………

5.​ Wood has such disadvantages as ………………

6.​ The main properties of stone are ………………..

7.​ The examples of man-made building materials can be ……………

8.​ Concrete consists of ………………….

9.​ An alloy of iron and other elements is called …………….

10.​ Petrochemicals are used to produce ……………..

11.​ Building materials are divided into …………………

12.​ Binding materials are used for ……………….

13.​ Natural building materials are ……………….

14.​ Artificial building materials are ………………..

 

VI. Translate the following sentences from Russian into English:

1.​ Строительные материалы должны соответствовать определённым требованиям.

2.​ Важно, чтобы строительные материалы были крепкими, долговечными и огнестойкими.

3. Самые распространённые строительные материалы – это сталь, бетон, кирпич и дерево.

4. Дерево – самый древний строительный материал.

5.​ Основными недостатками дерева является то, что оно горит и гниёт.

6.​ Свойства камня – механическая прочность, компактность, пористость, звукоизоляция, теплоизоляция и огнестойкость.

7.​ Кирпич может быть примером искусственного строительного материала.

8.​ Бетон – это смесь песка, цемента, щебня и воды.

9.​ Все строительные материалы можно разделить на три основные группы.

10.​ Для внутренней отделки используются вспомогательные материалы, такие как плиты, плитки, листы.

VII. Make up a plan to the text and render it.

VIII. Translate the following text in writing:

Concrete

Concrete is made by binding together particles of sand and gravel, stone or broken brick. The binding agent used is a paste of Portland cement and water in suitable proportions. When water is added to the cement, hydration takes place. This causes the whole mixture to set and harden, forming a solid mass. The sand, gravel or (broken stone) are termed aggregate; sand is known as fine aggregate, and gravel is course aggregate. Concrete can be made on a building site and poured into position as a wet mix, or it may be used as the material for making prefabricated units in a factory. That is why there is another classification into “in-situ” (or cast-in-place) concrete and “precast” concrete. (560)

 

IX. Read the text and make up a précis of the text:

Types of cements

Cements are substances which bind together the particles of aggregates (usually sand and gravel) to form a mass of high compressive strength (concrete). The most commonly used cement is Portland cement which may be of ordinary variety or rapid hardening.

Portland cement is made by mixing together substances containing calcium carbonate, such as chalk or limestone, with substances containing silica and alumina, such as clay and shale, heating them to a clinker and grinding them to a powder. The basic requirements for Portland cement cover composition, sampling procedures and tests for fineness, chemical composition, compressive strength, setting time and soundness.

Low heat Portland cement sets, hardens and evolves heat more slowly than ordinary Portland cement. It is used in large structures such as dams and massive bridge abutments.

White cement is produced by reducing the content of iron compounds in the cement through careful selection of the raw materials and using special manufacturing processes. Coloured cements are obtained by adding suitable pigments to white cement. These cements are mainly used for decorative purposes.

High alumina cement differs in method of manufacture, composition and properties from Portland cement. Its main advantages stem from its very high early strength and resistance to chemical attack. Heat evolution is rapid, permitting the concrete to be placed at lower temperatures than ordinary Portland cement. (1400)

X. Read the text and make up questions to the words given in bold type, say what new facts you have learnt from this text about reinforced concrete.