Translate the questions into Russian. Answer the questions consulting the text of the article.

1. What factors does the quality of concrete depend upon?

2. What is the main difference between plain and ferro-concrete?

3. What constructions is ferro-concrete used for?

4. What materials is concrete with cellular structure made up of?

5. What qualities does concrete with foamy structure possess?

6. What is its main disadvantage?

Read and translate the article.

The quality of concrete is known to depend on the properties of ma­terials it consists of. The amount of constructing materials is also of great importance. Among the kinds of concrete used in modern construction there are plain concrete and reinforced, or ferro-concrete. The usage of plain concrete is practically limitless. As to ferro-concrete, it is mostly used for construction of foundations, columns, girders and beams. This kind of concrete is also rather popular for constructing bridges, dams, and dock walls.

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Essential Course

Unit Eight. Concrete

Concrete being a universally used material, its new kinds are being constantly produced. Among others there exists concrete with cells. Its main quality is that it is made up of materials that emit gas and foam dur­ing the process of mixing the aggregates with water. It should be taken into account that concrete of this type possesses relatively light weight. It is mostly used for producing slabs, wall panels, and frame constructions. As we know, decrease in weight leads to a considerable decrease in strength. This quality is classified as a great disadvantage of cellular concrete.

122. Read the examples. Translate them from Russian. у

concreter — бетонщик

concrete mixer — бетономешалка

concrete frame — бетонный каркас, бетонная конструкция

concrete workability — пригодность бетона для обработки

Read and translate the article.

Silica Concrete

Among the aggregates concrete is composed of, there are heavy and light ones. Silica belongs to comparatively new types of concrete. Its struc­ture is rather special. It does not contain cement and is relatively light in weight. Besides, it is highly fire-resistant. Because of these and some other properties silica concrete is widely used in aviation and in building under­water constructions. But its disadvantages should be also taken into ac­count: because of its light weight its strength is considerably decreased.

123. Answer the following questions.

1. Which of the two kinds of concrete possesses greater strength — cel­lular or asphalt concrete?

2. What is the name of concrete having glass in its structure?

3. What is the meaning of the term 'nailable'?

4. What kind (kinds) of concrete has (have) practically limitless use?