Strengthening typically includes maintenance treatments such as the addition of thick surfacings, or the removal of part of the existing pavement structural layers and the addition of layers to restore or improve structural integrity and to increase the strength of the pavement. It is normally applied at the end of a pavementís structural life, when the pavementís problems are only structural of nature and no quality of service problems is anticipated in the medium to long term. Strengthening works are divided into the following works types:
- REHABILITATION ( R ): Rehabilitation is most effective on pavements that are exhibiting signs of structural deterioration (crocodile cracking and rutting, in particular) but not to such an extent that complete reconstruction (removal and replacement of the base and/or sub-base) will be more economical. Rehabilitation could include the reworking (but not removing) of the top 150 mm of the existing pavement to form a uniform platform for the addition of new pavement layers. Rehabilitation increases the structural capacity of the pavement to a condition that is very near or equal to that of an equivalent new pavement.
- RECONSTRUCTION (C): This is the removal of part (both bound and unbound layers) or all of the existing pavement layers and the construction of a new pavement. Reconstruction is appropriate when the pavement has structurally failed and the subgrade requires strengthening (including subdrainage construction) in order for the new pavement to perform properly. Since reconstruction consists of the removal of the structure of the existing pavement, it offers the opportunity to correct subgrade or base deficiencies, to slightly adjust the vertical geometry, to add drainage structures, etc. These options are not viable when the pavement is only rehabilitated. Reconstruction increases the structural capacity of the pavement to a level that is required for the medium to long term.
- BRIDGES (B): This refer to the works related to strengthen a under designed bridge to enable it to carry the required design loads.