The important general characteristics of hardened normal weight concrete and concrete structures, which are made with Portland cement, compared to other building materials and structures are as follows: · Concrete has a high compressive strength, so that it is particularly suitable for use in walls and columns.
· If it is not in the form of prestressed concrete, concrete has a low strength to weight ratio which results in general choice of steel or timber beams when there are long spans, and light loads which are applied.
· In building, the weight of concrete can provide good sound insulation, for example in floors.
Concrete has good fire resistance. This property often gives it an important advantage over steel. The fire resistance can be made a little lower by aggregates that contain silica.
There is no damage to reinforced concrete at temperatures which are lower than 300°C (580°F) and a limestone aggregate can withstand temperatures up to about 800°C (1,500°F) without great damage.
Unreinforced concrete is able to withstand amounts of tension, up to approximately 1/10 of its compressive strength. This property is of great importance as it allows concrete to withstand some shear stress without cracking.
Notes:
silica n. кремнезём
ответьте на вопросы к тексту
1. How many important general characteristics of hardened concrete structures are there?
2. What are they?
3. How can fire resistance of concrete be influenced?
4. What temperatures can limestone aggregate withstand?
5. How high are the amounts of tension that unreinforced concrete is able to withstand?
Грамматические упражнения
Упражнение 1. Найдите в тексте условное предложение. Переведите его на русский язык.
Упражнение 2. Найдите в тексте числительные. Прочитайте их.
Лексические упражнения
Упражнение 1. а) Переведите на русский язык приведенные ниже существительные:
sound, insulation, timber, floor, wall, choice, span, choice, importance, damage,
прилагательные и наречия:
light, a little, particularly, other, suitable, approximately,
служебные слова и обороты:
as follows, as, without, so that, for example, by, some, compared to,
глаголы:
contain, apply, provide, give, withstand, allow.
b) Если Вы не знаете слово, найдите его в словаре. Выпишите из словаря то значение слова, в котором оно использовано в тексте.
Упражнение 2. Найдите перевод слов списка А в списке В.
A выдерживать огнестойкость армированный бетон конструкционный бетон известняк напряжение сдвига часто B strength shear stress reinforced concrete structural concrete cracking fire resistance amount A растрескивание натяжение количество преимущество нагрузка прочность значение B tension load importance limestone withstand often advantage
Упражнение 3. Напишите предложения с каждым из перечисленных ниже слов:
durable - durability
important - importance
the boy's puppy is very cute. the boy's puppy grey. I like to play whis boy's puppy. (щенок мальчика очень милый, щенок мальчика серый, мне нравится играть с щенком мальчика).
the girl's monkey is very little, the girl's monkey is brown and black. I like to look at the girl's monkey. (обезьянка девочки очень маленькая, обезьянка девочки коричневая с черным, я люблю смотреть на обезьянку девочки).
Sam's bear is very very big, Sam's bear brown. I am afraid of the Sam's bear. (медведь сэма очень очень большой, медведь сэма коричневый, я боюсь медведя сэма)
Stephen William Hawking is a British theoretical physicist,cosmolgist and author. Among his significant scientific works have been a collaboration with Roger Penrose on gravitational singularities theorems in the framework of general relativity, and the theoretical prediction that black holes emit radiation, often called Hawking radiation. Hawking was the first to set forth a cosmology explained by a union of the general theory of relativity and quantum mechanics.
He is an Honorary Fellow of the Royal Society of Arts, a lifetime member of the Pontifical Academy of Sciences, and a recipient of the Presidental Medal of Freedom, the highest civilian award in the United States. Hawking was the Lucasian Professor of Mathematics at the University of Cambridge between 1979 and 2009.
Hawking has achieved success with works of popular sciense in which he discusses his own theories and cosmology in general; his "A Brief History of Time" stayed on the British Sunday Times best-sellers list for a record-breaking 237 weeks. Hawking has a motor neurone disease related to amyotrophic lateral sclerosis(ALS), a condition that has progressed over hte years. He is almost entirely paralysed and communicates through a speech generating device. He married twice and has three children.