1. The major difference between concrete block and clay brick is compressive strength.
Compressive strength is the property of any material to with stand pressure.
Going by the materials clay bricks and concrete bricks are made, the concrete bricks have much more compressive strength.
2. The second difference is water resistance.
Concrete bricks have more water resistance and don't absorb water, this makes them almost waterproof and is always beneficial for construction activities.
3. The shelf life of concrete is lesser than those of clay bricks. Concrete works good for around 60 to 100 years, while clay bricks have been known to last for 1000 years and more.
4. Concrete blocks are not environmental friendly, while clay bricks are made up of natural resources, and other than the baking of bricks, everything is fine with the environment.
5. Finally, as an architect, there is beauty in clay bricks and strength in concrete bricks.