It is commonly believed that rigid pavements cannot be built on subgrades which are still subject to vertical movements caused by settlement. There are two types of post constructional settlement : uniform settlement and differential settlement. This paper examines : (1) the effects of the differential settlement of the pavement subgrade. A distinction is made between differential settlement with a wavelength comparable to the length of the concrete slab and settlement with a broader wavelength; (2) the movements of the slab at the joints, due to subgrade deformation, which must be compatible with the type of joint. The joints must allow for the rotation of the two adjoining slabs. This may be possible if the gap between the joints is sufficiently wide; and (3) warping of the slab caused by thermal gradients. It is concluded that the construction of rigid pavements may not be absolutely ruled out but depends on the magnitude of the differential settlements occurring after construction
