Dear Sir, water curing plays an important role on strength development and durability of concrete. Curing takes place immediately after concrete placing and finishing, and involves maintenance of desired moisture and temperature conditions, both at depth and near the surface, for extended periods of time. Properly cured concrete has an adequate amount of moisture for continued hydration and development of strength, volume stability, resistance to freezing and thawing, and abrasion and scaling resistance.

I hoped that above information will be useful for you, i you need detail information please visit following link,

http://www.cement.org/learn/concrete-technology/concrete-construction/curing-in-construction

The test evaluates whether the appropriate materials were used with the appropriate w/c ratio. It does not tell you what the strength of the concrete is in a particular structure on a particular day. The variability of concrete on a jobsite is accomodated in the design by the various design factors.

Thank you very much David Sir, you have cleared my doubt with your answer.

Thanks for your information Sajjad Sir.