Chipsealing is the predominant resurfacing used on the state highway network in New Zealand. An important component of chipseals is the sealing chip layer that is applied to protect the binder layer and provide surface texture and surface friction. There are a number of specifications written to ensure that the sealing chip used is the correct size and shape, and that it has the appropriate ‘polished stone value’ (PSV), but no specifications on chip application rates exist. Early-life failures of chipseals are generally attributed to the binder, the binder application rate, or the weather; however, the sealing chip application rate may also contribute significantly to these early failures.
The objectives of this research, which was carried out between July 2006 and December 2009, were to:
This report documents the performance, over the first two years after construction, of chipseals that were constructed using different chip application rates.