Задания для самостоятельной работы

5. 1. Подчеркните Participle I и Participle II и установите функции каждого из них, т.е. укажите, является ли оно определением, обстоя­тельством или частью глагола-сказуемого.

1. The houses built in the last century needed reconstruction. 2. The appearance of our town is changing. 3. The subjects studied in the first two years are very important for future engineers. 4. If the loads are carried by the structural frame, consisting of columns, beams, trusses and arches, the building is called a skeleton construction. 5. The lecture delivered by the professor was on new methods of technology. 6. The results of the experiments discussed yesterday will be published. 7. A bus was moving along the street covered with stones.

5.2. Переведите следующие предложения на русский язык

1. Everyone can choose a profession he wishes. 2. The documents the secretary has registered are in the office. 3. Salt is the mineral we obtain out of sea water. 4. Any mineral a metal can be obtained from is called an ore. 5. The uses tunnels are constructed for are numerous. 6. Rocks are classified according to the material they consist of. 7. Water we wash with is brought to our home through a system of water supply. 8. The sphere of activity the study of geology can be applied to is tunnel building.

5.3. Переведите предложения, обращая внимание на различные значения AS

1. Man-made satellites had to use solar cells as a source of power. 2. The teacher as well as her students is going to the theatre. 3. As the train was approaching the station we went to the platform. 4. Specialists do not use solar cells in industry as they are too expensive. 5. Аs the idea was false, it wаs rejected. 6. The St. Petersburg Academy of Sciences was established as early as 1725. 7. The diamond is used for cutting metals as it is the hardest of stones.

5. 4. Translate the sentences, обращая внимание на герундий

1. You may use this instrument for measuring gas pressure. 2. Their aim is finding new ways of utilizing this polymer. 3. By cooling we can turn substances into solids or liquids. 4. The engineers were interested in testing the engine in various conditions. 5. One cannot transform water into steam without heating it. 6. What is the main reason for changing the schedule? 7. Ferro-concrete is used in building bridges and arches. 8. Maintaining constant temperature and pressure during the test was absolutely necessary.

TEXTS FOR READING

XVIII. BINDING MATERIALS

ash пепел, зола bed пласт bond сцепление colour цвет contour контур finger палец nail ноготь oxide окись pass переходить scratch царапать sift просеивать solution раствор stout толстый warmth теплота	alumina глинозем apartment квартира arris ребро, кромка capable способный coat слой, покрытие impurity примесь lath дранка, рейка partial частичный pigment пигмент plaster of Paris гипс sharp отчетливый shrinkage усадка suppose полагать unfit неподходящий			apparent явный, очевидный adhere сцепляться, прилипать assure убеждать, гарантировать attempt попытка, пытаться coating покрытие, слой fibre волокно, фибра likewise также, более того loosen ослаблять, разрыхлять movement движение occur случаться, происходить passage прохождение result иметь результатом set - set - set схватываться sufficiently достаточно
transparent прозрачный vegetable растительный		cattle hair щетина, волос, шерсть (животного) wall board сухая штукатурка, стеновая панель
eliminate устранять, исключать fit подходить, соответствовать lend - lent - lent давать, придавать moldings декоративные отливки of late years за последние годы on account of из-за, вследствие pulverize измельчать в порошок			calcine кальцинировать, обжигать carbonate карбонат, углекислота cementing materials вяжущие вещества otherwise иначе, в противном случае render приводить в какое-либо состояние take the place of занять место, заместить work up – wrought - wrought смешивать
mould = mold форма, формовать, отливать в форму rendering первый слой штукатурки, нанесение первого слоя штукатурки

We call binding materials such material which under the influence of certain physical conditions has the ability to harden passing from a liquid state to a solid one. From the most widely used binding materials we know gypsum, stucco, plaster, lime, cement.

Plaster is a material, capable of being moulded and troweled, applied as a finish for walls and ceilings in the interior of buildings. Upon setting it forms a hard surface which will satisfactory receive whitewash, paint or wall paper and acts as a partial insulation against the passage of heat, air and sound. According to the character of its base or cementing material plaster may be classed as lime plasters and gypsum plasters. These plasters will adhere to brick, concrete or other masonry surfaces which are provided by the design of the lath and by addition of cattle hair or vegetable fibre. The lathes may be made either of wood or of metal.

As found in nature the gypsum rock usually contains silica, alumina, lime carbonate, oxide of iron and other impurities. The large beds of gypsum are supposed to have been formed when the water is evaporated from solution of the mineral. Gypsum is so soft that it can be scratched with the finger nail. Sometimes it comes in transparent crystals called selenite. It is hard, fire resistant, sets quickly and is quite light in weight, but is never used in situations exposed to weather. In its calcined state it was used in early days as wall plaster. Of late years the manufacture and use of gypsum products such as plaster, hollow building tile and wall board have greatly increased. Pure gypsum is called alabaster.

Plaster of Paris is used for cast ornamental plaster work, and it is excellent for this purpose, producing hard surfaces, sharp contours and arrises and being sufficiently strong. It sets in 20 to 40 minutes which renders it unfit for wall plastering. When plaster is put on outside walls, it is called stuccoing.

Stucco is a plaster to be applied to the exterior of buildings to form a finishing coat. It is a very old method and was brought to a high development during ancient times in Greece, Rome and Egypt, where lime and volcanic ash were mixed to form the material of the stucco and pigments introduced to give it colour. Before the introduction of Portland cement, lime was much used to make stucco. Changed conditions in the present day and the apparent necessity for speed have now largely eliminated the use of lime for stucco, Portland cement having taken its place almost entirely.

Stucco is usually applied to walls of concrete, brick, hollow tile, concrete blocks or wood frame. In all cases the wall has to be stout and rigid and free from shrinkages and settlements, for any movement in the wall will cause cracks in the stucco. The bond between the stucco and the wall must likewise be assured, otherwise the coatings will not adhere and cracks and loosened areas will result. Coloured stucco has been used of late years to an increasing extent, a great variety of colours being developed, to lend warmth and interest.

Stucco in architecture in a composition of marble pulverized and mixed with plaster of lime, which being sifted and wrought up with water is used like common plaster. Architectural and sculptural ornaments, such as fruit, flowers, garlands, festoons, etc. are made of it. In the interior of buildings stucco work is generally applied to the ceilings of apartments, the mouldings, etc. In some countries a stucco of common mortar and of plaster is applied to the outside of houses and is extremely durable.

Lime mortar. If it were attempted to use lime as a plaster or mortar unmixed with other materials, wide cracks would occur on account of the shrinkage of the lime while hardening. Therefore sand is commonly used to mix with the lime to reduce the shrinkage and for economy of cost. The usual mixtures for mortar are 1 part lime to 2 parts of sand by volume.

XIX. CEMENT

clinker клинкер coarse крупный grey серый inch дюйм	accelerate ускорять call for требовать instead of вместо particle частица		blast-furnace доменная печь double удваивание, двойной, вдвое effect цель, результат, следствие formwork форма, опалубка
isle [ail] остров loss потеря price цена reach достигать sieve сито sturdy крепкий	saving экономия set схватывание set up вызывать stand выдерживать stripping разборка sudden внезапный		granulate дробить, гранулировать mixing water вода затворения on no account ни в коем случае range колебаться в пределах rough грубый, необработанный virtue достоинство, преимущество
bauxite ['bɔ:ksait] боксит generate производить kiln печь для обжига mesh отверстие (сита) objection недостаток perfection совершенство pozzolanic пуццолановый rank занимать место resemblance сходство restrict ограничивать take care of заботиться uncut необработанный		attack разрушать, поражать, разрушение by far несомненно, намного, значительно curing выдержка, вызревание (бетона) efficient действенный, эффективный fancy воображать, представлять себе grind - ground - ground измельчать high alumina cement глиноземистый цемент infinite ['infinit] бесконечный, безграничный resultant получающийся в результате ultimate strength предел прочности uniformity однородность, единообразие with the exception (of) за исключением

blast furnace Portland cement шлакопортланцемент

low heat Portland cement низкотермичный портландцемент

ordinary Portland cement обыкновенный портландцемент

rapid hardening Portland cement быстротвердеющий цемент

sulphate resisting cement сульфатостойкий цемент

The word "cement" comes from the Latin word "caementum" meaning pieces of rough uncut stone. The ancient Romans used cement to build their famous buildings, bridges and roads. The cement used by these ancient builders was made of the ashes of lava from Vesuvius and other volcanoes, and of lime obtained from burnt marble. With this cement the Romans built concrete foundations which are nearly as sturdy today as they were in the days of Julius Ceasar.

Now the word "cement" in its widest sense includes an infinite variety of materials and ranges from the clay used to bind stones and other materials together to the modern rapid hardening cements which are capable of binding three times their own weight of sand together in such a way that, at the end of 24 hours, they will stand a compression of several thousand pounds per square inch.

But in its more restricted sense the word practically always means Portland cement, as this is by far the most important cement used at the present time.

Portland cement received its name from a fancied resemblance in appearance to Portland stone - a natural stone found on the isle of Portland. It now ranks second only to steel as a structural material.

Ordinary Portland cement is so named because when set it resembles Portland stone in colour. It is manufactured by mixing clay with chalk or limestone in carefully controlled proportions. The mixture is then dried and heated in a horizontal kiln until it forms a hard clinker. The clinker is then finely ground, so that 90 per cent will pass a 170 mesh sieve. Ordinary Portland cement is used for most engineering and building work, and its manufacture has reached a high standard of perfection and uniformity.

The manufacture, chemical composition and general properties of rapid hardening Portland cement are similar to those of ordinary Portland cement as described above, with the exception that rapid hardening Portland cement has been given a longer and more efficient grinding with the result that it contains a higher proportion of the finer particles. The effect of the finer grinding is to accelerate the hardening of the cement after the final set has taken place, which allows the stripping of the formwork at an earlier age and a resultant concrete to take its load sooner.

Blast furnace Portland cement is manufactured from the same ingredients as Portland cement, but in the manufacturing process before grinding granulated blast furnace slag is added to the mixture. It has similar properties to ordinary Portland cement and is used in the same manner, its only virtue being that the addition of the slag to the mixture reduces the total heat required in manufacture, and which results in a saving in cost.

In the process of setting and hardening cement more heat is generated in using rapid hardening cement than using ordinary cement. This heat causes shrinkage and sets up internal stresses, particularly where the concrete is used in large masses, due to the losses of heat being more rapid near the surface of the concrete than internally. To overcome this objection low heat Portland cement is manufactured for use in such structures as dams, mass concrete walls and heavy foundations. The manufacturing process, chemical composition and general qualities of low heat cement are similar to those of ordinary Portland cement, with the exception that the clinker is more coarsely ground.

High alumina cement is manufactured by mixing bauxite rock with lime, after which the mixture is melted at a very high temperature and the resultant clinker finely ground in the usual way. On no account should this cement be mixed with Portland cement. It has a very high early strength and a higher ultimate strength than is obtained with any kind of Portland cement. A greater amount of heat is generated in the setting and hardening process with a result that it is not easily attacked by frost. It has the disadvantage of high shrinkage which calls for wet curing and on account of the high cost of the bauxite rock in some countries, for instance in England, the high temperature required for the manufacture and the increased cost of grinding the harder clinker, the price of the finished article is, at the present time, about double the cost of ordinary Portland cement.

Sulphate resisting cement is manufactured from blast furnace basic slag or pozzolanic rock granulated by sudden cooling. The chemical composition is controlled by the addition of Portland cement clinker or slaked lime where necessary. Its chief feature is that it contains a lower percentage of calcium than normal Portland cement, with the result that the finished cement mortar contains a lower percentage of free lime after setting.

White Portland cement is manufactured from similar ingredients and in a similar manner to ordinary Portland cement, but special care is taken to choose the type of clay which results in a white instead of the usual grey finished colour. By the addition of coloured pigments many coloured cements can be produced. These are very much higher in price than other cements according to the cost of the pigment used.

XX. CONCRETE

bubble пузырек castle 'замок cellar погреб cloth ткань dock док even даже facility легкость fill заполнять fresh свежий half половина pour лить ruin разрушать straw солома survive уцелеть though хотя	admixture примесь amount количество broken stone щебень entrain вовлекать era [iərə] эра, эпоха exhibit показывать foam пена, пениться in order to чтобы obsolete устарелый reduction снижение remains остатки revival возрождение specimen образец sprinkle обрызгивать treatment обработка			accomplish выполнять amount to доходить до bottom основание, дно, низ consist in заключаться в consistency консистенция crush дробить, измельчать crushed stone щебень damp влажный, увлажнять decrease ['dikri:s] уменьшение dilapidated полуразрушенный extraordinary чрезвычайный ferro-concrete железобетон footing фундамент, основание graving dock ремонтный док immerse погружать, окунать
break – broke – broken ломать broken brick кирпичный щебень cellular concrete ячеистый бетон damage повреждать, повреждение grade сортировать по крупности paste (цементное) тесто, паста placeability удобоукладываемость powdered порошкообразный sharp острый, остроконечный void пустота, вакуум; пустой			adaptable легко приспособляемые casing облицовка, покрытие, кожух coarse aggregate крупный заполнитель erection установка, сборка, монтаж fine aggregate мелкий заполнитель plain concrete неармированный бетон plasticiser пластифицирующая добавка retarder замедлитель схватывания universal всеобщий, универсальный up-to-date современный, новейший
be composed of состоять из ingredient составная часть hydration гидратация medieval средневековый monolithic монолитный out-of-date устаревший requisite требуемый		binder = binding agent вяжущее вещество exercise care проявлять заботу, внимание grading гранулометрический состав, сортировка indefinite неопределенный, неограниченный mass concrete монолитный / массивный бетон proportioning дозирование, проектирование смеси proportioning plant установка по дозированию
air-entrained concrete бетон с воздухововлекающими добавками fiber reinforced concrete фибробетон; бетон, дисперсно-армированный волокном in-situ concrete бетон уложенный на месте / на площадке reinforced concrete железобетон бетон / армированный бетон

Our most important building materials may be considered to be structural steel and concrete. The term "concrete" is used to describe a dense materials composed of cement and aggregate mixed with water. Concrete may be divided into two classes: mass or plain concrete and reinforced concrete (ferro-concrete) where it is necessary to introduce steel into the body of the material.

Mass or plain concrete was employed by the Egyptians and the Romans in the construction of aqueducts, roads, town walls, bridges and other massive work, generally with a facing of brickwork or masonry on the exposed surfaces and some specimens of the ancient work have exhibited extraordinary durability. Romans used it even in under-water structures some of which have survived till our time. A large part of the Great Chinese Wall (the third century before our era) was also built of concrete. One can see specimen of concrete work in the ruins of medieval castles and in the half dilapidated walls of the older towns of Europe. The concrete remains of the foundations of buildings built several thousand years ago have been found in Mexico. As cement was not known in those times, concrete was made of clay and later of gypsum and lime.

In the beginning of the 18^th century a special structural material was widely used in France where it was known under the term of "Beton". It was a production of a binder and clean-sharp sand. These constituents, when mixed together with a small amount of water, made a plastic compound which was hardened in moulds to the consistency of stone suitable for various building purposes.

The method of building in concrete has become partly obsolete until the more recent revival of the ancient Roman method that has produced satisfactory results. In 1814 Sir Robert Smirke was the first to have applied "Concrete building" in England on a wide scale. His method of making concrete consisted in using freshly calcined powdered lime mixed with sand and gravel with further admixture of water.

Concrete is made by binding together particles of sand and gravel, stone or broken brick. The binding agent used is a paste of Portland cement and water, in suitable proportions. When water is added to the cement, hydration takes place. This causes the whole mixture to set and harden, forming a solid mass. The sand, gravel (or broken stone) are termed "aggregate". The most important property of concrete is the facility with which it can be formed into large and strong monolithic structures.

The density of concrete and therefore many of its properties, depend upon the density of the aggregate. Therefore there is a broad division of concrete types into:

a) dense concretes - composed of heavy aggregates;

b) light-weight concretes - composed of light aggregates.

The aggregates are graded in size from fine to coarse in order to reduce the amount of void space to be filled by cement.

There are "cellular" concretes made by using materials which foam or form gas during the mixing of the concrete. These give a product of very light weight, because after setting it contains a large number of small voids. The reduction in weight is accompanied by a considerable decrease in strength. Another type of light weight concrete is made by "entraining" air bubbles in the mix to which a substance has been added to keep the bubbles stable during setting.

It is difficult to imagine modern life without concrete. Dams, dock walls and graving docks are classes of structures in which concrete is used in enormous masses. Concrete can be made on a building site and poured into position as a wet mix, or it may be used as the material for making prefabricated units in a factory. That is why there is another classification into "in-situ" (or cast-in-place) concrete and "precast" concrete.

Concrete is largely used as a casing around structural steel work for protection against fire. For foundations, footings, basement walls, cellar bottoms and fireproof floor construction, the use of concrete is almost universal, while the number and importance of the buildings whose columns, girders, beams and walls are entirely of concrete is rapidly increasing from year to year.

Now concrete is made in up-to-date machinery, great care is being exercised in regulating the proper proportioning of the mix. The ingredients are Portland cement, coarse and fine aggregate properly mixed with water. Plain or mass concrete though not so adaptable to architectural treatment can be used for almost all building purposes for which massive masonry or brickwork is suitable. It is practically suitable for the construction of monolithic foundation slabs to distribute the load from buildings, walls, piers and all classes of heavy erections.

XXI. CONCRETE AND REINFORCED CONCRETE

bending изгиб board доска harsh жесткий matter вещество network сеть pile свая pit карьер readily легко rise повышение silt ил	accept принимать appear появляться authorities власти content содержание ductile пластичный pack упаковывать plane выравнивать plywood фанера rod стержень, прут stretch растягивать			advantageously выгодно expand расширяться fall снижение, падение means способ, средство reinforce армировать sandstone песчаник supersede вытеснять sustain выдерживать uniform однородный value ценность, значение
a good deal of много anchorage анкеровка contract сжиматься curious любопытный deform деформировать overrate переоценивать plain ровный, гладкий reasonably достаточно		compressive stress сжимающее напряжение consistent with соответствующий, согласующийся deformed bar арматура периодического профиля incur expenses потерпеть траты, расходы medium carbon steel среднеуглеродистая сталь mild steel мягкая сталь, сварочная сталь prestress предварительное напряжение shearing stress скалывающее напряжение
alternative альтернативный bar стержень (арматуры) be composed of состоять из contamination загрязнение direct направлять; прямой drawn wire тянутая проволока fix фиксировать, закреплять indispensable обязательный opposite противоположный retaining wall подпорная стенка room место, пространство safe безопасный, надежный strip разбирать опалубку welded fabric сварная сетка			ample просторный, достаточный assist помогать, содействовать draw – drew – drawn вытягивать ensure обеспечивать, гарантировать hook крюк; зацеплять; гнуться in service в работе, в эксплуатации incorporate вводить, смешивать put forward выдвигать, предлагать deleterious вредный, вредоносный bend – bent – bent изгибаться, гнуться reasonable приемлемый, умеренный skin покрывающий слой, оболочка tensile stress растягивающее напряжение workability удобообрабатываемость
В. S. S. = British Standard Specification Британский Стандарт expanded metal цельнорешетчатый металл, просечно-вытяжной металлический лист high tensile steel сталь с высоким сопротивлением разрыву igneous изверженный, вулканического происхождения joint совместный, комбинированный; соединение, стык rolling mill прокатный стан (цех); вальцовая мельница

Reinforced concrete is a building material in which the joint functions of concrete and steel are advantageously utilized. Being brittle, concrete cannot withstand tensile stresses, and it cannot therefore be used in structures subjected to tensile stresses under load. But if steel is introduced into concrete it changes the property of the monolith.

Like any other stone material, concrete offers a good resistance to compressive loads. In service two oppositely directed stresses appear in reinforced elements which can successfully withstand bending loads.

There are two kinds of reinforced concrete: with ordinary reinforcement and concrete with prestressed reinforcement. To reinforce ordinary concrete structures is to introduce steel rods in stretched zones of concrete elements. Reinforced-concrete structures and elements are widely used both for residential houses and industrial buildings. Depending on the application of reinforced-concrete structures all kinds of concrete - heavy, light and heat insulating may be employed.

The idea of strengthening concrete by incorporating in it a network of small iron rods was developed in the 19^th century and ferro-concrete was introduced into engineering practice. Concrete expands and contracts with rise and fall of temperature and it is a curious and important fact that the rate of expansion is almost the same as that of steel.

Reinforced concrete is the combination which is now almost indispensable in civil engineering work. The fundamental basis of the ferro-concrete combination is that concrete is provided to sustain the compressive stresses and to act as the universal binding material of the system, while steel is provided to withstand the tensile stresses and to assist in resisting the shearing stresses.

The use of reinforced concrete construction is adapted to varied uses in foundation work thus retaining walls of ample strength can be readily constructed in places where there is no room for a wall of mass concrete. Ferro-concrete piles have largely superseded timber piles as a means of transmitting heavy loads. Ferro-concrete is used in building bridges and arches. Reinforced concrete is most extensively used in housing and industrial constructions, where the prefabricated section method has been employed on a particularly wide scale.

Reinforced concrete has been in use as a structural material since early Roman times, but only at the end of the latter half of the 19^th century scientific principles were put as a basis for structural design. In the present century reinforced concrete began to be used extensively. The basic theory which was developed at that time is used and accepted today very much in its original form, although many alternative theories have been put forward by investigators from time to time.

The principal materials used for reinforced concrete are: cement, coarse aggregate, fine aggregate, water, reinforcement and shuttering.

The most commonly used cements are: Ordinary Portland cement, Rapid hardening Portland cement, Blast furnace Portland cement, Low heat Portland cement, High alumina cement, white and coloured cements, Sulphate resisting cement.

Most common coarse aggregates are: crushed granite or other igneous rock, crushed sandstone, crushed limestone, pit gravel, sea or river gravel, crushed brick, special light-weight aggregates.

Aggregates should be composed of clean, hard durable particles, free from chemical contamination, coatings of clay or silt, or any other deleterious material. The aggregate should be uniformly graded between the smallest and largest size, but the largest pieces should be as big as possible, consistent with efficient handling and placing between the reinforcement.

Fine Aggregate (Sand). This can be composed of the same basic rocks or gravel as described above, but natural pit or river sand is to be preferred. Great care must be taken in using other crushed rocks to ensure that the material is uniformly graded and reasonably free from particles below B.S.S. I00 mesh sieve.

Water. Water must be free from chemical impurities or organic matter and reasonably free from silt. The quantity of water used in mixture must be carefully controlled because the strength of concrete decreases rapidly with an increase in the water content. The amount of water used affects the consistency and workability of the mixture, and these are normally measured by the tests.

Dry mixes are usually harsh and of low workability, consequently a good deal more effort is required in packing concrete into the forms.

Reinforcement. Reinforcement may be: mild steel plain round or square bars, deformed steel bars, skin stressed steel, drawn wire, high carbon steel and steel welded fabric or expanded metal.

It is essential that plain bars should be ductile to allow for easy bending to shape. This is not so important in the case of deformed or skin stressed bars because the bond resistance between the concrete and the steel is very much higher, and less bending and hooking is required.

In recent years, in America, a good deal of research work has been carried out on deformed bars, and as a result of this work most authorities in the U.S.A. will allow, by their Regulations, higher bond stresses for design purposes. This has encouraged the use of deformed bars to such an extent, that for practically all reinforced concrete work carried out in the United States at the present time, deformed bars are used. The rolling mills supply these bars without any increase in cost. The value of using deformed bars as reinforcement cannot be overrated. The following are some of the advantages: 1. Smaller anchorage lengths are required and steel weight is reduced. 2. Less bending and hooking are required which results in a saving of labour. 3. The higher bond resistance results in a stronger and safer structure. 4. The deformations permit more accurate fixing, and consequently their use ensures greater efficiency.

Shuttering. Shuttering may be: planed boards, plywood, steel, precast concrete. All shuttering should be made and erected in such a way that it can be easily stripped and will leave a perfect surface that needs no further treatment. It is far better to spend a little more on making and erecting shuttering than to incur expense in making good the surface after the shuttering is stripped.

XXII. TYPES OF CONCRETE

be likely вероятно composite смесь cotton хлопок lining облицовка mass масса namely а именно prove оказываться retain удерживать situation ситуация thin тонкий	acrylic акриловый alkaline щелочной attack разрушение criterion критерий failure разрушение flexibility гибкость hostile враждебный in situ на площадке stable устойчивый tank цистерна, бак		beneficial выгодный degree степень, градус for из-за, вследствие hence следовательно ideal [ai'diəl] идеальный in spite of несмотря на ineffective безрезультатный limit граница, предел limitations недостатки lose – lost – lost терять to advantage выгодно unique [ju:'ni:k] уникальный unlimited неограниченный weakness недостаток
distinctive отличительный, характерный matrice = matrix матрица, вяжущее, раствор rayon [΄reiɔn] вискоза, искусственный шелк serviceability эксплуатационная надежность
dynamic [dai'næmik] динамический equally в равной степени, одинаково hydrate ['haidreit] гидрат, гидроокись lack не иметь, испытывать недостаток static статистический, неподвижный watertightness водонепроницаемость		be unlikely маловероятно, едва ли critical решающий, критический exceptional исключительный fly ash летучая зола, зола-унос practise применять, осуществлять superior лучший, превосходный

for the best advantage наилучшим образом, наиболее выгодно

hydraulic cement гидравлический цемент, гидравлическое вяжущее

Which material can be used for the best advantage for a particular part of the building, depends as well on the kind of load to which it is subjected and on the shape of the part. That the development of the metallurgical and machine-building industry made possible mass production of prefabricated large-size concrete and reinforced concrete structural elements is a well-known factor to influence the choice of materials. It is most advantageous to employ reinforced concrete in such structural elements. Using prefabricated or precast elements builders perform a considerable amount of building work not in situ but at a factory where highly organized and mechanized technological processes of production are practised.

The function of engineers is to produce strong, durable structures as economically as possible. The basic requirements of an engineering material are flexibility, tensile strength and toughness. Concrete, like other engineering materials, lacks all these to the required degree, and many of its weaknesses have to be overcome by steel reinforcement or prestressing,

The distinctive properties of fibre-reinforced cement composites are improved tensile and bending strength, greater ductility, greater resistance to cracking, and hence, improved impact strength and toughness. Probably the most important property of fibre-reinforced concrete to be accepted as a construction material, particularly for load-bearing applications, is its durability.

Plastic fibres such as nylon, polypropylene and polyethylene are known to be stable in the strongly alkaline environment of the hydrating cement matrix. Fibres such as cotton, rayon, acrylic and polyester are, however, subject to alkaline attack and are ineffective as reinforcement in Portland cement products. Plastic fibres are also stable in air and water, but lose strength at temperature of the order of 100° C.

In spite of the fact that fibre reinforcement of cement matrices is a relatively recent development, there have been many practical applications of fibre-reinforced concrete. The most widely used fibre among plastic fibres is polypropylene, which has been used extensively for pile shells and also for non-load bearing components for its crack-resisting properties in place of conventional steel reinforcement.

This wide range of applications is remarkable and speaks of the distinctive properties of this new material, namely, its resistance to cracking and hostile environment and its superior static and dynamic properties. The number of applications seems to be unlimited from non-load bearing elements to load-bearing structural applications.

The exceptional water-tightness of fibre-reinforced composites is likely to find applications for lining of tanks, pipes, etc. and in the manufacture of liquid-retaining structures and in sea structures.

The superior fire-resisting qualities of glass- and steel fibro-reinforced concrete are likely to find application in the design of thin section roof panels. The flexibility of fibre-reinforced cement composites makes it ideal for secondary structural components, and particularly for permanent shuttering.

In spite of the wide and varied applications of fibre-reinforced concrete, it is still very much in the development stage, and there is the need to understand their limitations as much as their advantages. It is unlikely that there will be one unique fibre for all situations - rather a combination of fibres may prove more advantageous. Bond failure of the fibres appears to be most critical factor, but strength is not the only criterion in design, serviceability and limit stages are equally important.