9.BUILDING MATERIALS AND ENGINEERING COMPONENTS..


BUILDING MATERIALS AND ENGINEERING COMPONENTS.
The designer must be able to select and adapt such materials of construction that will give the most effective result by the most economical means. In this choice of materials for any work of construction, the civil engineer must consider many factors. These factors include availability, cost, physical properties of materials and others.
Timber, steel and concrete all vary, sometimes over considerable ranges in the properties desired by the engineer. Lime, gypsum and cement are the three materials most widely used in building construction for the purpose of binding together masonry units, such as stone, brick and as constituents of wall plaster. Cement is furthermore the most important elements in all masonry structures, Portland Cement like other materials can to some extent be modified to suit a particular application. The scope for such purpose - made cements has led to the development of an increasing variety such as high alumina cement, blast- furnace slag and pozzuolanas.
The most important building materials may now be considered to be structural steel and concrete. Concrete may be considered an artificial conglomerate of crushed stone, gravel or similar inert material with a mortar. A mixture of sand, screenings or similar inert particles with cement and water which has the capacity of hardening into a rocklike mass is called mortar.
With the rapid growth in the employment of precast- concrete products, and particularly of wall panels, slabs, beams, etc.. to serve a multitude of building needs, this industry has inevitably incurred an obligation to maintain and improve the quality of the products. A great number of plants producing precast reinforced- concrete elements are now in operation in our country and abroad.
The industry processing the natural compounds of silicon is called the silicate industry. It embraces the production of cement, glass and ceramics. Clay mixed with water and sand is moulded into bricks, which are then dried and baked. The materials used to make silicate bricks are white sand and slaked lime.
Glass Production. The initial materials for the production of ordinary glass are mainly soda Na2CO3 limestone CaCO3 and sand SiO2.A mixture of these substances is heated in a bath- shaped furnace.
When it cools, the liquid mass of glass does not become hard at once. Definite portions of the cooling semi liquid mass are taken from the bath. By machine methods glass sheets, tubes, etc., can be drawn continuously from the molten mass.
Foamed glass is a high- porosity heat insulating material, available in block made of fine- ground glass and a frothing agent. Foamed glass is widely used in prefabricated house building, to ensure heat insulation of exterior wall panels and in industrial construction. Foamed glass has a high mechanical strength, is distinguished by moisture, vapor and gas impermeability. It is non- inflammable, offers resistance to frost, possesses a high sound adsorption, and it is easily sewn and nailed.
Nowadays plastics can be applied to almost every branch of building, from the laying of foundation to the final coat of paint. Laminate is a strong material manufactured from many layers of paper or textile impregnated with thermosetting resins. This sandwich is then pressed and subjected to heat. Laminate has been developed for both inside and outside use. As a structural material it is recommended for exterior work.
Glass tlber reinforced plastic panels are produced in the USA. The sheets or slabs designed to simulate to exactness hand- placed textural tiles, inlaid carvings, natural wood with the deep graining effects, brick, marble, stone, etc. This material has good weather resistance. It is recommended to be installed in the windows on the ground floor. The dangers of shattered glass and flying objects are eliminated. Its color range is unlimited with a "standard" selection of 50 solid colors and 15 multi-hued combinations.

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