Text A. The Most Important Building Materials

1. All the buildings erected nowadays are of two main types: they are intended either for housing or industrial purposes. While projecting any of them a designer must be able to select and adapt such materials of construction that will give the most effective result by the most economical means. To make his choice a civil engineer must consider many factors: availability, cost, physical properties of materials being the most important. Which material can be used to the best advantage for a particular part of building, depends as well on the kind of load to which it is subjected and on the shape of the part.

2. At present the main building materials are considered to be timber, stone, brick, concrete, steel, light metals, glass and plastics. Timber was one of the first materials used by man for constructional purposes. The buildings made of stone or brick are durable and fire-proof, they have poor heat conductivity.

3. Portland cement was produced more than a century ago. From the time of its first production there was a steady and gradual improvement in its compressive strength.

4. Concrete made with natural hydraulic binders was used in antiquity, particularly by the Romans. After the decline of the Roman Empire the art of making concrete has been forgotten, and the revival came much later.

5. Reinforced concrete is hardly 100 years old but its practical application in building began 90 years ago. Today reinforced concrete is used in all civilized-countries as one of the most important building materials. One of the properties of concrete is its compressive strength.

6. Cast-in-place concrete is mixed and placed on the building site. Precast concrete is produced ina factory and used for the production of prefabricated elements. Usually they are made of dense concrete but in recent years the use of lightweight concrete has increased considerably. A precast concrete plant consists of two parts: a large mixing installation and a casting yard where the plastic concrete mass is placed in moulds. It is an advantage of this method that prefabricated elements of a constantly high quality can be produced to a very high standard of precision. Another important advantage of precast concrete is that the work on the building site is largely replaced by operations in the factory where working conditions are far better. This allows continuous production which is not influenced by weather conditions; therefore this method is of special interest for countries with long hard winters.

4. Are these statements true or false? If they are false, say why. Use the following phrases:

I can’t agree to this statement because…

Just the contrary…

I think…

To my mind…

1. All buildings can be divided into two main types.

2. To choose a proper material a civil engineer must consider many factors.

3. Concrete is the first building material.

4. Portland cement was produced more than two hundred years ago.

5. One of the properties of brick is its compressive strength.

6. Precast concrete is mixed and placed on the building site.

7. Cast-in-place concrete is produced ina factory.

5. Study the text and answer the following questions:

1. What must a designer be able to do while projecting any of the buildings?

2. What factors of materials are taken into account?

3. What are the main building materials?

4. Which of the building materials was the first to be used for construction purposes?

5. Which of the building materials was used by the Romans?

6. What is the difference between cast-in-place and precast concrete?

7. What are the advantages of precast concrete?

6. For each definition write a word from the text:

1. An engineer who designs or maintains different constructions.

2. Powdery substance made by calcining lime and clay, mixed with water to form mortar.

3. A composition of gravel, sand, cement, and water, used for building.

4. A small, usually rectangular, block of fired or sundried clay, used in building.

5. Wood prepared for building.

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