It is very important to ensure that the pavement is not contaminated during the construction process. Therefore it may be more practical to leave installation of the bedding material and paving blocks until most of the construction on the site is complete. The solution to this is to install the sub-base material and then overlay this with Dense Bitumen Macadam (DBM) to form a temporary site access road. Site traffic can then use this road for access during the construction phase. Once access by construction traffic is no longer needed the DBM layer can remain in place. The layer is firstly cleaned and then 75mm diameter holes are cored through to allow water to drain through to the sub-base aggregate. The 75mm diameter holes should be cored through on a 750 mm grid and filled with 6 – 2.3mm grit. The required thickness of the DBM layer required will be dependent on the amount of construction traffic using it.