Samenvatting
When designing concrete pavements, the bearing capacity of the subgrade and possible subbase layers is usually expressed as the modulus of subgrade reaction or k value. The effect of subbase layers on the bearing capacity of the substructure can be expressed by an increase of the k value of the subgrade. The VNC (Vereniging Nederlandse Cementindustrie) Handleiding Betonwegen (VNC Manual on Concrete Roads) provides a number of tables of such values, and the AASHTO guide provides a nomogram. Some aspects of this method are discussed in this paper.