Whereas ionic bonds join metals to non-metals, metallic bonding joins a bulk of metal atoms. ... Sodium metal is therefore written as Na, not Na+. ... Both of these factors increase the strength of the bond still further. ... Heat capacity: This is explained by the ability of free electrons to move about the solid.
The answer is in the photo.
As the concrete has cement, gravel, crushed rocks, sand, and water of different physical state and can be separated by physical methods hence it should be called as a mixture.
As the components have significant physical boundaries which clearly identify their presence, the mixture is heterogeneous and not homogeneous.
Thus this is a concrete is a heterogeneous mixture of cement, gravel, crushed rocks, sand, and water