Read and translate about Portland cement

Read the text and find new words from the text.

Before-Reading

THE MOST IMPORTANT AND WIDELY USED BUILDING MATERIALS

I was helped to start the reaction

She is told to decompose the substance

You will be shown the lab

They were asked to write the test

Exercise 5. Chose and read correct translation of English sentences.

1) Они попросили написать контрольную работу.

2) Они спросили, писать ли им контрольную работу.

3) Их попросили написать контрольную работу.

1) Вы покажите лабораторию.

2) Вы будете в указанной лаборатории.

3) Вам покажут лабораторию

1) Она говорит, что вещество разлагают

2) Она говорит о разложении вещества

3) Ей велят разложить вещество

1) Я помог начать реакцию

2) Мне помогли начать реакцию

3) С моей помощью реакция началась

Unit11

1. Discuss the following:

• What materials are used in building construction?

2. Try to guess the meaning of the following words. Use the dictionary
if you need:

* physical properties of material

* a building

* a technology

* a construction

* a measure

• a proportion

• a component

* concrete

* cement

* a stone

3. Make up your own sentences with the words from Ex 2.

While-Reading

3. Find and translate all the sentences containing the following words:

* concrete

* component measuring

* construction

* technology

* proportion

* building

4. Reading for general meaning. Read and answer the following questions to the text:

* What is a modern technology?

* What materials' forms are very important in all masonry structures?

* What factors must the civil engineer consider?

* What can you tell something about the most accurate method of measuring proportions?

* What kind of material is the most widely used for the purpose of binding together masonry units such as a stone and a brick?

* What material is also known to be the most important com­ponent of concrete?

* What kind of material may be considered an artificial conglomerate of crushed stone?

* What can you tell about an important class of cement?

* What is high aluming cement?

* What materials are mostly used in Russia?

* What can you tell about building technology in Russia?

Building materials are very important in the construction. But it is more important for any designer to select and adapt such building materials of construction that will give the most effective result by the most economical means. In this choice of materials for any work of constructions many factors must be considered by the civil engineer. These factors include availability, cost, physical properties of materials and others.

Practically, all buildings materials have their advantages and disadvantages. That's why some materials are used most widely in building construction for the purpose of binding together masonry units. Among them are lime, gypsum and cement. Last material forms very important elements in all masonry structures, such as stone, a brick. Since the time of its introduction a gradual improvement of Portland cement quality has led to the elaboration of rapid hardening Portland cement, or «high early strength». Portland cement like other materials can be modified to suit a particular application. Later developments include low heat and sulphate resisting cements. The scope for such purpose - made cements has led to the development of an increasing variety such as high alumina cement, blast-furnace slag. They may be also white and coloured cements. Alumina cement has an extremely high rate of strength increase. Portland blast-furnace cement has greater resistance to some forms of chemicals.

So, cement is the most important component of concrete. Concrete is even less uniform than many other materials. Concrete may be considered an artificial conglomerate of "crushed stone, gravel or similar inert material with a mortar". A mortar is a mixture of sand, screenings or similar inert particles with cement and water. It is very important to know everything about proportions. The most accurate method of measuring proportions is to weigh the required quantities of each material. This may be done whether the proportions are based upon volumes or weights. This method is being extensively used in road construction and in many central mixing and in central proportioning plants. It is also widely used in large building constructions. Sometimes timber, steel and concrete are all vary over considerable ranges in the properties desired by the engineer. Even steel varies considerably in its microstructure.

6. Read the text again and complete the following sentences:

• Timber, steel and concrete all vary, sometimes over considerable ranges in the properties desired by...

•...is even less uniform than many-other materials.

* The designer must be able to select and... materials of construction that will give the most effective result by the most...

* The gradual improvement in... from the time of its introduction led to the elaboration of

* High alumina cement is a...

* It has an extremely...

* The most important building materials may now be considered to...

* A... of sand, screenings or similar...

•...is a specific characteristic of this material.

7. Read the following statements and say whether they are true or false. Correct the false statements:

* Lime, gypsum and cement are not the three materials most widely used in building construction for the purpose of binding together masonry units, such as stone, brick and as constituents of wall plaster.

* Cement is not the most important component of concrete.

* It has an extremely high rate of strength increase which is, owing to the violence of the chemical reaction, accompanied by a considerable evolution of heat.

• The most important building materials are steel and concrete. Concrete may be considered an artificial conglomerate of "crushed stone, gravel or similar inert material with a mortar".

* A mixture of sand, screenings or similar inert particles with cement and water which has the capacity of hardening into a rocklike mass is called mortar.

* Timber, steel and concrete all vary, sometimes over considerable ranges in the properties desired by the engineer.

* Portland blast-furnace cement has greater resistance to some forms of chemicals.

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