Are added to the concrete to obtain desirable characteristics

Decorative stones or crushed glass are added to the surface of concrete for a decorative ______.

From construction, demolition and excavation waste are used as partial replacements of natural aggregates

Text-based exercises

Reading-Comprehension exercise

Ex.7. Say which of the following issues are considered in the text. If they are, say which sentences from the text deal with the issue concerned.

- advantages of concrete,

- types and uses of concrete,

- curing, setting and hardening of concrete

- possible failures,

- different methods of preventing failures,

- different admixture and their uses,

- substitutes for cement,

- the common ingredients of concrete,

- kinds of aggregates,

- the difference between concrete and cement.

Ex. 8. Insert into the sentences the right word or word group from the box.

hydration process; gravel limestone; the workability; stone-like material;recycled aggregates;permeability; tiny air bubbles; chemical admixtures; the hydration; exposed aggregate finish;bonding agents; develops strength

1. The coarse aggregate in concrete is normally _______ or granite.

2. The water reacts with the cement, which bonds the other components together and creates a ________.

3. The water and cement paste hardens ______ and over time.

7. Accelerators speed up ______ (hardening) of the concrete.

8. Air-entrainers add and distribute ______ in the concrete increasing the concrete's durability.

9. Plasticizers increase _______ of plastic concrete to place it with less consolidating effort.

10. ______ are used to create a bond between old and new concrete.

11. A moist environment in curing promotes hydration and lowers ______ for higher quality.

12. Freezing before the curing is complete interrupts the ______.

Ex. 9. Complete the sentences

1. Concrete consists of cement as well as other ….

2. In the chemical process of hydration water reacts with ….

3. The water and cement paste ….

4. Both fine and coarse aggregates are used to ….

5. Recycled aggregates are used as ….

6. Decorative stones such as … are sometimes used as a decorative "exposed aggregate" finish.

7. Chemical admixtures are materials in the form of powder or fluids ….

8. Retarders slow the hydration of concrete and ….

9. Air-entrainers add and distribute ….

10. Plasticizers increase the workability "fresh" concrete allowing ….

11. Corrosion inhibitors are used to ….

12. … concrete must be cured once it has been placed and achieved initial setting. 13. A moist environment durin curing promotes hydration, since ….

14. The amount of heat generated ….

15. Allowing the concrete to freeze before the curing is complete will …..

16. Improper curing can lead to ….

Ex. 10. Complete the following sentences using English equivalents in­stead of the Russian words and word-combinations. Use Text 1 for support.

1. Concrete is a construction material that consists of cement as well as (других вяжущих материалов, заполнителя и воды и химических примесей).

2. Concrete solidifies and hardens after mixing and placement (благодаря химическому процессу, известному как гидратация).

3. Concrete is used more than (любой другой искусственный материал на планете).

4. The water and cement paste (твердеет и набирает прочность) over time.

5. Recycled aggregates from construction, demolition and excavation waste are used as (взамен натуральных заполнителей).

6. Decorative stones (наподобие кварца, мелких речных камней или стекольный бой) are added for a decorative "exposed aggregate" finish.

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