Text A. Concrete

1. There are many important building materials nowadays, concrete being one of them. Concrete may be considered an artificial conglomerate of crushed stone, gravel or similar inert material with a mortar. The fundamental object in proportioning concrete is the production of a durable material of requisite strength, watertightness and other essential properties at minimum cost. To attain these properties careful attention must be given to the selection of cement, aggregate, and water.

2. The most accurate method of measuring proportions is to weigh the required quantities of each material. It is widely used in large building construction, but in small building construction the less accurate method of measuring proportions by volumes being frequently used. Workability and strength are chief control tests made on concrete. To be able to undergo high compressive loads is a specific characteristic of this material.

3. Since concrete is only strong in compression, it will quickly fail if it is used for elements like beams and floor slabs, which are subjected to high bending forces. If it is reinforced with iron or steel bars, however the elastic metal will take the rigid forces, and the rigid concrete will resist the compressive forces. The reinforcing techniques developed the structural possibilities of concrete becoming almost unlimited. In its reinforced form it combines the elasticity of iron and steel with its own initial plasticity and final rigidity, an almost ideal combination of properties that makes it the most suitable of all building materials.

4. Reinforced concrete has become so popular because of its resistance to fire and weather, its durability and great strength under static and dynamic loads. It has, however, a number of disadvantages, low thermal insulating value being one of them. Besides it is very heavy and requires forms in which it must be held until it has hardened, and in winter it must be kept warm during setting.

5. Prefabricated reinforced concrete elements and modern reinforcing methods being used, the above mentioned disadvantages are now being eliminated or at least minimized. Reinforced concrete is used for many types of structures, it being now the main building material for factories, office buildings, power stations, bridges, etc. In recent years it has become the preferred material for housing.

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. Concrete is a natural building material.

2. The main property of concrete is its durability.

3. There are three accurate methods of measuring proportions while making concrete.

4. Concrete will resist compressive forces if it is reinforced.

5. Concrete is an ideal material, it has no disadvantages.

6. Reinforced concrete is used for building of power stations.

5. Study the text and answer the following questions:

1. What is concrete produced of?

2. What are the main properties of concrete?

3. How did reinforced concrete appear?

4. What are the main disadvantages of reinforced concrete?

5. How can the disadvantages of reinforced concrete be eliminated or at least minimized?

6. What types of structures is reinforced concrete used for?

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

1. Composition of gravel, sand, cement, and water, used for building.

2. Produced by human art or effort.

3. A number of things or parts forming a mass.

4. Careful, precise.

5. Strengthen or support, esp. with additional material.

6. Concrete with metal bars or wire embedded to increase its tensile strength.

7. Manufacture sections of (a building, reinforced concrete etc.) prior to their (its) assembly on the site.

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