Reinstatement materials and compaction requirements have been specified in order to safeguard the pavement structure in and adjacent to the reinstatement. Any rapid or substantial settlement in a reinstatement may therefore indicate a potential reduction in the stability of the adjacent pavement structure, as well as potential defects in the reinstatement.
There will be cases in adverse circumstances where the correct application of this Code will still result in levels of settlement in the reinstatement that do not meet the requirements of S2.5 for structural integrity. For example, the type and condition of the adjacent ground or pavement structure may limit the degree of compaction that can be achieved, so influencing the amount of settlement that could occur.
Any engineering investigation is intended only to determine the likelihood and extent of any further settlement, and the most cost-effective and convenient method of restoring the structural stability and surface performance of failed sections of a reinstatement to a satisfactory condition.
In the case of large or deep excavations, it may be appropriate for the authority and the undertaker to agree an extended interim guarantee period, with additional interim surfacing materials laid to restore the running surface. When no further consolidation or settlement is considered likely, a permanent binder course and surface course may be laid, and the permanent guarantee period initiated. In any event, the location and extent of any re-excavation should be mutually agreed, taking full advantage of any bound materials already in place.