Vocabulary notes

to distinguish различать, распознавать

to engage заниматься чем-либо

medieval средневековый

to reveal открывать, обнаруживать; разоблачать

expert опытный, квалифицированный

persistent стойкий; постоянный

to codify приводить в систему

millwright монтажник; слесарь-монтер

apprentice ученик, подмастерье

available доступный; имеющийся в распоряжении

to be reluctant быть вынужденным

chair кафедра

EXERCISES

I. Read the text “Civil Engineering” and follow the information.

II. Find in the text the English equivalents for:

впервые был использован; вновь признанная профессия; творения древних и средневековых времен; история изобретательных гениев и постоянных экспериментирований; как отдельная дисциплина; ведущие инженеры; опытные знания; ученик монтажника; основанный в 1826 году; первая кафедра по гражданскому строительству.

III. Summarize the information of the text “Civil Engineering”.

IV. Read the text “Civil engineering functions”. Speak on the problems raised in it and make reports.

Building materials cement

Cement is a binding material used in construction and engineering, often called hydraulic cement, typically made by heating a mixture of limestone and clay until it almost fuses and then grinding it to a fine powder. When mixed with water, the silicates and aluminates in the cement undergo a chemical reaction; the resulting hardened mass is then impervious to water. It may also be mixed with water and aggregates (crushed stone, sand, and gravel) to form concrete.

Cement made by grinding together lime and a volcanic product found at Pozzuoli on the Bay of Naples (hence called pozzuolana) was in ancient Roman construction works, notably the Pantheon. During the middle Ages the secret of cement was lost. In the 18^th century John Smeaton, an English, rediscovered the correct proportions when he made up a batch of cement using clay limestone while rebuilding the Eddystone lighthouse off the coast of Cornwall, England. In the United States, production of cement at first relied on processing cement rock from various deposits, such as those found in Rosendale, N.Y. In 1824, Joseph Aspdin, an English bricklayer, patented a process for making what he called Portland cement, with properties superior to its predecessors; this is the cement used in most modern construction.

Modern Portland cement is made by mixing substances containing lime, silica, alumina, and iron oxide and then heating the mixture until it almost fuses. During the heating process dicalcium and tricalcium silicate, tricalcium aluminum, and a solid solution containing iron are formed. Gypsum is later added to these products during a grinding process. Natural cement, although slower-setting and weaker than Portland cement, is still employed to some extent and is occasionally blended with Portland cement. Cement with high aluminum content is used for fireproofing, because it is quick-setting and resistant to high temperatures; cement with high sulfate content is used in complex castings, because it expands upon hardening, filling small spaces.

Of the various Portland cements, the following varieties are now generally available:

a) Ordinary Portland cement, the cheapest,

b) Rapid-hardening cement, which is slightly more expensive because it is ground rather finer and is thus more chemically active,

c) Sulfate-resisting cement which has a special chemical composition to resist sulfates, and can be used in ground which contains them,

d) Air-entraining cement for building roads which may suffer from frost damage,

e) Low-heat cement for massive construction such as dams where the speed at which the heat is given off must be reduced, and slow development of strength does not matter.

These are the main Portland cements. Different cement, which should be mentioned, is high-aluminum cement. High-aluminum cement is usually black, unlike Portland which is grey, but reaches “Portland 28-day” strength in twenty-four hours with correspondingly high heating and it must therefore not be cast in masses which are thicker than 60cm. This common high-alumina cement costs roughly three times as much as Portland. White Portland cement is also obtainable and more expensive than ordinary. It is used for making white concrete or for painting or plastering concrete.