Concrete

Concrete is one of the most important building materials. It is difficult to imagine modern structure without concrete. Concrete is the very building material, which led to great structural innovations. The most important quality of concrete is its property to be formed into large and strong monolithic units of any desired shape.

Concrete is a mixture of cement, sand, gravel and water. It is mixed and poured into forms that hold it in place until it hardens. The crystals forming in the process of making concrete stick together in a very hard artificial stone.

The characteristics of concrete depend upon the quality of the materials used, grading of the aggregates, proportioning and amount of water. The most important requirements for concrete are: it should be hard, strong, durable, fire-resistant and economical.

Concrete can be divided into two classes: plain concrete and reinforced concrete where it is necessary to introduce steel.

Reinforced concrete is a combination of two of the strongest structural materials: concrete and steel. Concrete has an adequate compressive strength, but its tensile strength is low. On the other hand, steel has a high tensile strength. Suitable combination of these two materials provides resistance to both compressive and tensile stresses.

Plain concrete can be used for almost all building purposes. Reinforced concrete is used in building bridges, arches, dams, for structures under water, for foundations, columns, beams, etc. The use of concrete and reinforced concrete is almost universal.

11. Read the text once more and find the equivalents to the following Russian word combinations:

трудно представить, большие и прочные монолитные блоки, очень твёрдый искусственный камень, гранулометрический состав заполнителя, количество воды, самые важные требования, достаточная прочность на сжатие, высокая прочность на разрыв, сжимающее и растягивающее напряжения.

12. Complete the following sentences:

1) Concrete is the very building material which led to … 2) The most important quality of concrete is … 3) Concrete is a mixture of … 4) The characteristics of concrete depends upon … 5) The most important requirements for concrete are … 6) Concrete can be divided into two classes … 7) Concrete has an adequate compressive strength, but … 8) Suitable combination of concrete and steel provides resistance to … 9) Reinforced concrete is used in building …

13. Agree or disagree with your partner, begin your phase with “That’s right” or “That’s wrong”:

1) Concrete is a natural building material.

2) The most important quality of concrete is its property to be formed into large and strong monolithic units.

3) The characteristics of concrete depend upon the quality of the materials used, grading of the aggregates, proportioning and amount of water.

4) There is only one type of concrete used in construction.

5) Concrete has an adequate tensile strength.

6) Suitable combination of concrete and steel in reinforced concrete provides resistance to both compressive and tensile stresses.

7) Prestressed concrete enables lighter construction than ordinary reinforced work.

14. Answer the questions of the test “Building materials”:

Test

“Building materials”

1. Building materials should be:

1. hard, plastic, easily fastened and fire-dangerous;

2. durable, hardly fastened, soft, fire-resistant;

3. fire-resistant, hard, durable, easily fastened.

2. The most commonly used materials are:

1. plastics, concrete, wood, glass, stone, brick, steel;

2. glass, concrete, ferro-concrete, plastics;

3. electricity, central heating, air-conditioning, refrigeration.

3. Building materials differ in:

1. fire-dangerousness, hardness, durability;

2. durability, fire-resistance, softness;

3. hardness, fire-resistance, durability.

4. Building materials are divided into ---- main groups:

1. four

2. three

3. five

5. Main building materials are:

1. stone, glass, timber and plastics;

2. metals, lime, rocks and concrete;

3. timber, rocks, stones, metals.

6. Cementing materials are:

1. cementing, gypsum, lime;

2. binding, lime, concrete;

3. cements, gypsum, binding.

7. Secondary materials are used for:

1. exterior;

2. interior;

3. auxiliary;

8. We use the main building materials for:

1. bearing structures;

2. joining different planes;

3. interior finishing.

9. Natural building materials are:

1. concrete, stone, glass, lime;

2. timber, cement, sand, plastics;

3. lime, stone, timber, sand;

10. Artificial building materials are:

1. metals, clay products, sand;

2. brick, lime, ferro-concrete;

3. concrete, cement, clay products.

15. Using information from the texts “Building materials” and “Properties of Building Stone” or “Building materials” and “Concrete” speak briefly about building materials and in details either about building stone or about concrete. Follow this plan:

1) The text is about …

2) The first part of the text is devoted to …

3) Further, it is said that…

4) It is pointed out that …

5) The text tells that …

6) The text also discusses …

7) The text ends saying that …