15-11-2012, 01:39 PM
CONSTRUCTION OF POLICE HEAD QUARTER
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INTRODUCTION
The building is defined as any structure what so ever purpose and of whatsoever materials constructed and ever part thereof whether used as human habitation or not. For this practical training.
I reported at Rajasthan State Road Development & Construction Corporation LTD at Lalkothi , Jaipur. I have reported to Mr. O.P Gupta (Project Director) at RSRDC Lalkothi furthers ordered me to join project site. The site incharge Mr. R.P.Sharma and Mr. SUdama Sharma (Project Officer) meet me at the site and gives me brief introduction of this project as under.
BUILDING MATERIAL
A building structure is composed of different types of the material these materials are either called as building material. The material use in the building on basis of the avaibility and cost. For construct a building the essential building material are as follow:
Cement
The cement often called the magic power is a fine ground material consisting of compound of lime ,silica alumina and iron. When mixed with water it forms a paste which ardened and bind the aggregates (sand,gravel, crushed rock, etc) together to form a durable mass called the Concrete. Cement is the binder that holds concrete and mortars together. Which is why it play the most critical role in giving strength and durability to your building. Cement uses for domestic building such as home are basically of three types.
PortlandSlagCement: Portland slag cement (PSC) conforming to IS: 455 A combination of good quality blast furnace slag (from the iron steel industry) with clinker (which makes the OPC) and gypsum.
Portland Pozzolana Cement: Portland pozzolanacement (PCC) confo- rming to IS: 1489 A combination of flyash (from thermal power plant) with clinker and gypsum. pozzolana cement is prepared by grinding Portland cement clinker with pozzolana. This type of cement is largely used in marine structure.
Reinforcement Steel
RCC stands for reinforced cement concrete. To enhance the load carrying
capacity of the concrete it is reinforced with steel bars of different diameters provided in an appropriate manner. Such concrete is called reinforced concrete and the bars are called the reinforcement. These bare are provided at various locations to resist the internal forces, which are developed due to the loads acting on the structure. Reinforcing steel contributes to the tensile strength of the concrete. Concrete has low tensile, but high compressive strength. The tensile deficiency is compensated by reinforcing the concrete mass through insertion of plain or twisted mild steel bars. Both branded and unbranded bars are available. It is wise to buy good brands the names of which are marked on the steel. During construction make sure that steel reinforcement is provided exactly as the engineering design specification.
REINFORCEMENT CEMENT CONCRETE
Plain concrete is very strong in compression but its tensile strength is only about 1/10th of the strength in compression. So, the use of the plain concrete is limited to the structure in pure compression. Steel being equally strong in compression and tension, is, there fore, used to reinforce the concrete in a suitable way so that it can be used to build supporting structure where tension also develops. Concrete, thus reinforced is known as “reinforced concrete”. This combination is made because long steel bars can develops its full strength where it cannot carry equal amount of compressive force due to its buckling which is caused by the slenderness. Thus, the combination of concrete and steel bars has proved to be ideal, as the two material are used to resist the stresses for which they are most suitable.
cement concrete
1) The concrete develops very good bond with the surface of the steel bars and , there fore the stresses are transferred from one material to the other which cannot resist individually.
2) The steel possesses a high tensile strength, a high modulus of elasticity and same coefficients of expansion and contraction as concrete. Due to equal linear coefficients, no internal stresses are set up within reinforced concrete due to variation in temperature.
3) The coating of cement grout or paste on the surface of the reinforcement protects it from corrosion and at the same time it does not chemically react with the reinforcement.