Pavements consist of,
i) sub-grade which is the ground itself.
ii) the sub-base i.e the foundation material able to withstand different forces that may affect the structure.
iii) the bedding layer does what its name says i.e acts as a buffer between the sub-base.
iv) the pavior.
For you the client, it is normal that your ultimate objective is to have a structure that has a beautiful appearance and structurally stable. Engineers have worked hard for centuries and have come up with different types of pavements that have the constituents that were mentioned above. Because of the different uses of different pavements, certain designs have been created. Two main types have been developed namely flexible and rigid.
FLEXIBLE PAVEMENTS
The flexible pavement allows minimum motion between the pavers which are either permeable or not. Because of new regulations all pavements constructed between the road and dwelling should be permeable and if not then they should be constructed in a way that allows percolation of water or should not be of an area exceeding 5 square meters.
The pavers can be of any shape or size though care should be taken in their selection so as to satisfy regulations. Similarly a suitable sub-base is filled into the excavated area and screeded to required gradients and compacted to a relevant degree to allow interlocking with the sub-grade. After compaction, bedding material is filled to standard depth. The pavers are then laid and final compaction is done.
RIGID PAVEMENTS.
Similar legislation as for flexible pavements also applies in this case.
In the rigid pavement, there is no motion allowed between the constituents of the pavement. Popular rigid pavements are, tarmac and concrete. Both of them have sub-grade and sub-base similar to that in the case above.
In the tarmac case, the base course is made of bitumen bound to an aggregate of a larger size than that of the surface. The building process involves applying the materials screeding and compacting them using a roller.
In the concrete case, the base course is made of concrete, depending on the use of the pavement, some require some reinforcement to allow for larger traffic. Some clients are satisfied with an unpaved surface. In paved situation where block pavers, slabs or flags are used, a mortar bedding is bedded on the concrete base and the paver is placed and adjusted to give relevant gradient.
