Современные проблемы промышленного и гражданского строительства на занятиях английского языка. Кузьмина Е.В. - 36 стр.

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certain elements are added to the concrete composition. They serve to neutralize

the alkali (щелочь) in the liquid glass and convert it into a water-insoluble

(нерастворимый) compound. Thus, during the course of the neutralization of

the alkali, free silica is evolved (выделяется кварц) from the liquid glass in the

form of a gel which serves as a binder.

Chemically resistant concrete has not found wide application because it is

completely permeable to aggressive, corrosive solutions. The Soviet scientist

V. P. Kirilishin decided to provide and improved alkali-metal-silicate based

concrete. In accordance with his invention high-silica-alkaline glasses are

practically insoluble in water even at elevated temperatures and are not suitable

for the production of liquid glass. However, when subjected to heat in the

presence of finely divided quartz sand, the high silica alkaline glass on the

finely divided particles of the quartz sand.

In the present invention the silica binding agent is not present in the form

of a gel that has the more thermodynamically and chemically stable crystalline

form of free silica, namely quartz. This leads to good chemical, physical,

thermal and mechanical characteristics for the binder and the chemically

resistant concrete.

Text D. Concrete structures

The world has suddenly become aware of the great resources of ocean

and their potential for providing many of man's most pressing needs: energy,

food, transport, minerals and waste-disposal. However the seas present an

extremely hostile environment, requiring cooperative efforts by many

engineering disciplines in order to achieve the necessary structures.

These structures must be strong, save, durable and economical.

Reinforced prestressed concrete meets these criteria extremely well for many of

the proposed structures, both fixed and floating. These include drilling,

breakwaters, ocean pipelines, offshore nuclear power plants; ocean bridges and

tunnels; offshore airports and terminals; Arctic Ocean structures; Barges, ships

and floating stable platforms; offshore expositions and even cities; sea floor

chambers etc.