The basic ingredients of concrete are water, graded stone aggregates, and a cement binder.
Cement is manufactured from limestone in a heated kiln process and reduced to a powdered form.
When combined with water the cement reacts chemically to bind the aggregates to form an inert and durable material. Concrete has high compressive strength, and when combined with steel reinforcing strands, it can have tensile strength as well. When formed and finished appropriately, concrete can provide both structure and architectural finish to interior and exterior elements. Only a small amount is recycled in any form. Two dry concrete recycling plants operate in the Denver area, crushing concrete into road base and back fill material.