Identification

• Concrete blocks are formed from gravel aggregate, sand and cement. Most commonly, they are installed as building foundations, walls, fence lines or columns.
  
  

Features

• Filling concrete blocks serves a variety of purposes. In the case of columns and fence lines, filling the blocks creates a heavy, but sturdy, formation to hold up weight or to withstand winds and natural elements.
  
  

Significance

• Another application of filling concrete blocks is when building a foundation and walls. In areas prone to earthquakes, tornadoes or hurricanes, the concrete blocks can be shored up with steel rods. The rods are placed through the hollow portions of the blocks deep down into the ground. The blocks are then filled, creating a sturdy foe against the elements.