Раздел IV

BUILDING MATERIALS TEXT A

1. Переведите интернациональные слова.

substance, fibrous, variety, synthetic, categorize, natural, select, mani­pulation, cubic, cement, aggregate, cementitious, granite, proportion, ingredient, mixture, aluminium, decorative, popular, paste.

2. Запомните слова и словосочетания.

construction purpose — цель строительства;

fibrous рlant — волокнистое растение;

industrial setting — промышленная установка;

availability — наличие, доступность, возможность использования;

transportation ease — лёгкость/простота транспортировки;

predominant material — преобладающий материал;

chemical admixture — химическая добавка;

mass concrete structure — конструкция из монолитного бетона;

functional extension — функциональный ряд (бетонных изделий);

to vary proportions — менять пропорции;

partial replacement— частичная замена;

manufactured aggregate— промышленный/фабричный заполнитель.

3. Прочитайте текст и выполните задания. Building Materials (I)

Part One

Building materials are any materials used for construction purpos­es. Since earliest times many natural substances, such as clay, sand, wood and rocks, even twigs and leaves, and ice (!) have been used to construct buildings. To continue the list of natural building materials fibrous plants and animal skins come along.

Apart from naturally occurring materials, great variety of man- made products, more or less synthetic, are in use. All building mate­rials can be generally categorized into two sources — natural and syn­

thetic. [Natural building materials are those that are unprocessed or minimally processed by industry, such as lumber or glass. Synthetic materials are made in industrial settings after much human manipula­tions (plastics and petroleum based paints, for instance).]⁰ Both natu­ral and synthetic building materials are widely used for construction purposes.

Choice of building materials in modern construction industry is almost unlimited. [To select appropriate materials for a construction is the concern of designers and engineers, and the main factors to be considered are the materials' physical properties, availability, trans­portation ease, cost, environmental impacts, etc.]°

Concrete is used more than any other man-made material and has been the predominant building material in this modern age. As of 2006, about 7.5 cubic kilometres of concrete are produced each year — more than one cubic metre for every person on Earth. It is com­posed of cement (commonly Portland cement) and other cementitious materials such as fly ash and slag cement, aggregate (generally a coarse aggregate made of gravels or crushed rocks such as limes- tone*, or granite, plus a fine aggregate such as sand), water, and chemical admixtures. [Mass concrete structures, reinforced con­crete, prestressed concrete, and precast concrete are the most widely used; types of concrete functional extensions in modern days.]⁰

There are many types of concrete available, created by varying the proportions of the main ingredients. [The finished product can be tailored to its application with varying strength, density, or chemical and thermal resistance properties.]° (1 800 п.зн.)

Part Two

[Portland cement is a basic ingredient of concrete, mortar, and plaster.]° It is the most common type of cement in general usage. It consists of a mixture of oxides of calcium, silicon, and aluminium.

Portland cement and similar materials are made by heating limestone (a source of calcium) with clay, and grinding this product (called clinker) with a source of sulfate (most commonly gypsum**).

Fine and coarse aggregates make up the bulk of a concrete mix­ture. [Recycled aggregates (from demolition, construction, and exca­vation waste) are increasingly used as partial replacements of natural aggregates, while a number of manufactured aggregates, including air-cooled blast furnace slag and bottom ash are also permitted.]⁰ De­corative stones, small river stones or crushed glass are sometimes added to the surface of concrete for a decorative finish, popular among landscape designers.

Combining water with a cementitious material forms a cement paste by the process of hydration. The cement paste glues the aggre­gate together, fills voids within it, and allows it to flow more freely.

[Chemical admixtures are materials in the form of powder or flu­ids that are added to the concrete (usually less than 5%) to give it cer­tain characteristics not obtainable with plain concrete mixes.]⁰

* Limestone is a hard sedimentary rock, composed mainly of calcium carbonate or dolomite.

** Gypsum is a soft material occurring in nature as crystals and transparent cleav­able masses called selenite. (1 250 п.зн.)

4. Соедините части предложений (AB), чтобы получить закон­ченное высказывание.

А.

• Aggregates may usually include...

• The factors for selecting building materials are...

• Cement consists of...

• Recycled aggregates are increasingly used...

• Concrete is composed of...

• Cement paste is formed...

• The most widely used types of concrete extensions are...

в.

• their physical properties, availability, transportation ease, cost, environmental impacts, etc.

• as partial replacements of natural aggregates.

• mass concrete structures, reinforced and precast concrete.

• cement, aggregate, water, and chemical admixtures.

• by the process of hydration combining water with a cementi- tious material.

• sand, natural gravel, and crushed stone.

• a mixture of oxides of calcium, silicon, and aluminium.

  5. Ответьте на вопросы.

• What natural substances have been used to construct buildings since earliest times?

• What sources can be all building materials generally catego­rized into?

• Whose concern is it to select appropriate materials for building purposes?

• How much concrete is produced each year?

• What are chemical admixtures added to the concrete for?

5. Составьте план текста.

6. Пользуясь планом, перескажите текст.

ТЕХТ В

1. Переведите интернациональные слова.

fiber, gravity, massive, block, optimize, stress, distribute, optimal, press, service, conserve, reconstruction, resource, locally, confuse, term, stucco, contact, stable, asphalt, deposit, minor, competent, con­veyor, separate.