Abstract

Among the various properties of concrete, its compressive strength is considered to be most important and is taken as index of its overall quality. The water cement ratio directly affects the strength of concrete. Low water cement ratio possesses high strength and its high value gives lower strength. But it is restricted to a certain limit. There should not any shrinkage cracks and creep in concrete due to temperature variation. It is also important to know the flexural strength to estimate the load at which the concrete members may crack. Concrete is most widely utilized man made material, without which modern architecture and construction would not be possible. Today humans consume no material except water in such tremendous quantities. According to Roman history, concrete was firstly made in 9000 BC. Good concrete has to satisfy performance requirement in the plastic and hardened state. In the plastic state concrete should be workable and free from segregation and bleeding. Where segregation is the separation of coarse aggregate and bleeding is the separation of cement paste from main mass. In its hardened state concrete should be strong, durable, impermeable and it should have minimum dimensional changes