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Identify the topic of each paragraph of Text 5B.
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21. Complete the sentences choosing the best variant
corresponding to the contents of Text 5B.
1) Concrete has the great advantage because
a) it is made from hydraulic cement, crashed stone or gravel,
and sand.
b) it is made in any shape.
c) it has to be worked to the required shape.
2) Concrete is the building material that
a) can be made on the building site.
b) can't be delivered ready-mixed to the building site.
c) can support walls, floors, beams, columns, girders.
3) The strength of concrete is determined by the quantity of
a) sand and gravel.
b) water.
c) cement.
4) To make concrete stronger
a) it should be put under loads.
b) steel rods should be embedded.
c) it should be put under compression or tension.
5) The reinforced concrete beam is compressed because
a) it is stretched.
b) the stretching force is removed.
c) holes are made through it.
114 I Английский языкдля студентов строительных специальностей
UNIT 5. BUILDING MATERIALS
j 115
6) Lightweight concrete can be made by using
a) processed clinker or air.
b) different types of shuttering.
c) exposing the stones.
22. Read Text 5C "Bricks" and find the answers to these questions. Discuss your answers with your groupmates.
a) Why are bricks considered to be the most lasting of man-made building materials?
b) What ways are bricks made in?
c) What is the soft-mud process characterized by?
d) What does the stiff-clay process consist in?
e) What is specific of the pressed brick process?
f) When are bricks ready for firing?
g) What process produces the bricks of light sandy colour?
h) What advantages do lighter bricks have?
i) What factors does the colour of clay bricks depend on? j) What are oversize bricks called?
• TEXT 5C
Bricks
Good bricks are the most lasting of man-made building materials. They are not much affected by the weather and, if a building catches fire, brickwork resists the effects of fire longer than most other forms of construction. Bricks are fairly small and light and therefore easy to handle, but when they are bonded together with mortar they make extremely strong structures. Good brickwork needs very little maintenance, lasts for a long time, and looks attractive.
Brick is formed in three ways: the soft-mud, stiff-clay, and pressed brick processes. In the soft-mud process, clay is mixed with water to form a stiff paste which is then thrown by hand or forced by machine into wooden or metal box-like moulds of the size of a brick. Sand or water is sprinkled on the inside of the moulds to
keep the clay from sticking. The sand or water also gives the brick a pleasant finish. Such bricks are called sand-struck or water-struck bricks. The soft, wet bricks are removed from the moulds for drying.
In the stiff-clay process, the ground clay is mixed with water in a long trough containing a revolving shaft with blades. The blades mix the clay with water as they revolve and at the same time push it forward into an extrusion machine. This forces it through a rectangular opening. It is extruded in a long bar of the length and width of a brick. A moving belt carries the clay bar to a cutter, which is a metal frame with a number of wires stretched across it. The wires are brought down on the bar to cut it into bricks, which are then dried. Bricks formed in this way are known as extruded wire-cut bricks.
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In the pressed brick system, the clay is semi-dry, and is pressed by a heavy machine into metal moulds under such high pressure that the clay particles hold together. Because pressed brick has very little water, it needs little drying.
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After being formed, bricks are loaded on rail trucks and pushed into driers, and then into kilns to be fired. Drying takes two to three days and then the bricks are ready for firing.
Clay is the material most often
associated with bricks, but since the
late 19th century other materials have
been used. For example, calcium
silicate bricks, sometimes known as
sand lime bricks, are made by
pressing a mixture of moist sand and „,,,,...
f.. °,.,.... The world s highest
lime into brick shape by machine. с -. u t
_,.,,,, brick tower of
The bricks are then steamed under s Martin,s church in
high pressure in an autoclave. This Landshut, Germany,
process produces bricks of an completed in 1500
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