The base of a flexible pavement is the most important layer and it is constructed between the sub-base and the asphalt layers.

Her role is to  take over the vertical forces and deliver these to the layers below, with the minimum achievable settlements of the soil. Of
course the thickness of the base (and of the sub-base) increases while the strength of the soil decreases, but the exact thickness which is
calculated varies a bit according to the method and the acceptances.

The base consists of a number of layers, the material of which may be aggregates with a bonding material or without. The bonding material
used may be asphalt or cement. In the specific construction, as you can see no bonding material is used. See photos below:
Construction & Consolidation of the base of a flexible
pavement - Attiki odos s.a. Athens, October 2000

Please if you know any links to papers just contact us.
photo1: sub-base (brown) and base before the consolidation of the base.

Of course the aggregates used in the base are always of a better quality than those of the sub-base.

The consolidation

It is very important for the good quality construction of the base  that in the calculated moisture(with the Proctor method) the base will be
enough consolidated. The consolidation of the base is a function of:

  • the thickness of the layer.

  • the consolidation energy which will be acting This energy is a function of the weight of the steam-roller, of the type of the steam-roller,
    and the number of transitions.

Text References: Nicolaides, Οδοποιία, οδοστρώματα-υλικά, ελεγχος ποιότητας,Θεσσαλονίκη 1996