The quality of the supporting surface is a very important factor that affects the behavior and durability of the pavement . Consequently, this support layer will be perfectly leveled and compacted, reaching 100% according to the Proctor compaction test . It must have the appropriate degree of humidity at the time of placing the concrete .

In order to be employed you must meet the following conditions:

• It must be stable and not alter outdoors.

• Provide the concrete with a uniform color.

• Be chemically compatible with lime and not decompose under the action of the lime released during the setting of the cement.

• Do not alter the mechanical resistance of the concrete or the stability of the volume.

• React with the cement and water in the concrete, imbibing it.

• Provide great surface resistance to concrete.