What is the value of modulus of elasticity of concrete?

According to the "Structural Engineer's Pocket Book" concrete commonly has a modulus of elasticity in the range of 17 - 30 GPa.

The exact value of modulus of elasticity depends on the concrete's uniaxial compressive strength after a cure time of 28 days.

These values are related using the following:

Emc = 4700 x sqrt(UCS)

Where:

Emc = Elastic Modulus (MPa)

UCS = Uniaxial Compressive Strength of Concrete after 28 days (MPa).

Source:

Cobb, F. (2009). Structural Engineer's Pocket Book, Second Edition. London, Butterworth-Heinemann.