Measuring, predicting and specifying moisture in granular pavements with thin bituminous surfacings

For granular pavements with thin bituminous surfacings, it is imperative to prevent moisture infiltration into the pavement, which is one of the main factors in determining both the serviceability and longevity of road structures. This paper discusses several methods to minimise moisture ingress by means of road design and construction (effects of geometry, materials and compaction) and sub-soil drainage. It also discusses techniques for measuring and predicting long-term moisture conditions in both granular bases and subgrade. Longterm monitoring field trials have also been conducted to provide long term field data of moisture movement in granular pavements. Accelerated pavement testing (APT) trials have also been conducted to examine the effects of moisture and compaction on performance of crushed rock bases. A strategy for incorporating moisture factors into material specification, construction and pavement design is also presented