The compressive strength of the material is the main parameter to be correctly defined. It shows the material’s actual state and giving the engineers the ability to decides the correct necessary decision. Retrofitting or demolishing the existing reinforced concrete structures is usually taken based on this parameter that is generally obtained via destructive or non-destructive methods. In some cases, especially in a large-scale region, the compressive strength is not obtained via test due to the difficulty and the high cost of performing the tests. In such a case, the use of Strength-for- Age curves can be carried out where concrete strength is plotted as a function of the construction years.