CONCRETE AS CONSTRUCTION MATERIAL

CONCRETE AS CONSTRUCTION MATERIAL

concrete is the most widely used man-made construction material in the world and is second only to water as the most utilized substance on the planet. It is obtained by mixing cementing materials, water, and aggregates, and sometime admixtures, are filled by the smaller particles (fine aggregates) the voids of fine aggregate are filled cement water paste which in addition to filling the voids of fine aggregate, coats the surface of fine and coarse aggregates and binds them together as it cures, thereby cementing the particles of the aggregates together in a compact mass.
                                                                     The strength, durability and other characteristics of concrete depend upon the properties, of its ingredients, on the proportions of the mix, the method of compaction and other controls during placing, compaction, and curing. the popularity of the concrete is due to the fact heat from the common ingredients, it is possible to tailor the properties of concrete to meet the demands of any particular situation. The advances in concrete technology have paved the way to make the best use of locally available materials by judicious mix proportioning and proper workmanship, so as to produce concrete satisfying performance requirements.

The key to producing a strong a durable and uniform concrete. CONCRETE AS CONSTRUCTION MATERIAL is the following.

CONCRETE AS CONSTRUCTION MATERIAL

•  CEMENT
• AGGREGATE
• STEEL
• WATER

CEMENT

       Portland cement, the most widely used cementing ingredient in present-day concrete comprises phases that consist of compounds of calcium, silicon, aluminum, iron, and oxygen.  Cement is used as the binding material and acts as a binder for coarse and fine aggregates. Generally, ordinary portland, cement is used to form concrete. Initial setting time of good cement should not be less than 30 minutes and the final setting time should not exceed 10 hours.

 AGGREGATE

               There are primarily naturally occurring, ind=ert granular materials such as sand, gravel, or crushed stone. However, technology is broadening t include the use of recycles materials and synthetic products.
              The granular material generally inert chemical such as natural sand, gravel, crushed stones and air-cooled iron blast furnace slag are called aggregates. If only CEMENT is used for the construction, the concrete will result in shrinkage and ultimately cracks develop. So as to avoid these cracks, aggregates are used. These aggregates are bound together by means of cement. The aggregates are classified into two categories such as final and coarse aggregates. The material which is passed through sieve no 480 is called fine aggregates and which retained on sieve no 480 is called coarse aggregates. These aggregates should be clean. sharp, angular, well graded, hard, durable and free from foreign matters.

STEEL

           The Steel reinforcement is generally in the form of round bars of mild steel. The diameters of bars vary from 5 mm to 40 mm. Sometimes the square bars or twisted bars or ribbed-bars or ribbed-tor steel are used as steel reinforcement.
        Following are the reason as to why mild steel has been adopted as reinforcing material
         These are a proper band between CEMENT concrete and mild steel. Hence, it enables concrete to transmit its stresses to steel.
        The coefficient of linear expansion of steel is almost the same as that of concrete. Hence o internal stresses are set up within reinforced concrete members due to rise or fall in temperature.
        Deformed or twisted bars which are made of mild steel have considerably high yield stress, tensile strength, and bond strength.

 WATER

           The water to be used in making concrete should conform to the drinking water standard. It is less expensive but the most important ingredient of concrete. The water, which is used for making concrete should be free from acids, alkalies, salts, oil, grease and decayed vegetable matters. The amount of water should be of that, which will produce concrete of required quality.