Characters of Cement Concrete

          The concrete is the construction material material made by mixing of cement, fine aggregate, coarse aggregate and water in proper proportions. The complete concrete is obtain when these four products are mixed at correct proportion. By adjusting the proportions of the different materials a wide range of strength can be achieved.
          The cement and water are the active agents of the concrete. the fine aggregate and the coarse aggregate are the inactive agents in the cement concrete. The chemical reaction between the cement and other materials added are begins when the water is added to it. The process begins by the water in the concrete is called hydration process. The hardening of concrete is  occur by the hydration process.so, the concrete should be kept wet for 30 days up to its satisfactory level to made concrete hard.
          In the curing process the water is poured over the concrete to reduce the shrinkage of concrete. while the low temperature also affects the strength of concrete.
          Concrete can made into desired shape when it is mixed or at semi liquid state. It is used at dams , roads, bridges,houses, buildings and other constructions,etc.

          The concrete pocess only the compressive strength so it can resist only the compression. But the Beams, columns, walls, pedestals should bear both compressive and tensile strength. To make concrete to pocess tensile strength reinforcement in provided in it. The Reinforced cement concrete can resist stretching, bending and twisting. The reinforcing steel, which may taken in the form of rods, bars, or mesh contribute tensile strength.Plain concrete does not easily withstand stresses such as wind action, earthquakes, and vibrations and other bending forces and is therefore unsuitable in many structural applications. The strength of concrete can be modify by the water-cement ratio.
           The durability of concrete is its strength . The stronger the concrete the more durable it is. The major factor controlling the strength of concrete is cement - water ratio. However, the strength of concrete is completely obtain by the use of well graded sand and coarse aggregate.
           The ideal concrete mix is one with enough water required for complete hydration of the cement. However this result in a mix too stiff to pour in forms. A mix fluid enough to be poured in forms contain water combine in concrete.
           The strength of concrete is measured in kilogram per square centimetre or pounds per square inch of force needed to crush a sample of a given hardness. Concrete's strength is affected by environmental factors such as temperature,rainfall and moisture.