Low-granulometry surface dressings
In some road works, use of certain dual gap-graded asphalt mixes (2/6 or 4/6) leads to under-utilisation of the 2/4 grade. Both grades are produced by the same fabrication process in volcanic rock quarries, but the 2/4 grade is frequently under-used and needs to be stored definitively.
To meet reasoned use of resources criteria, one of the principles of sustainable
development, we tested this low-granulometry material in traditional road surfacing
applications. Three pilot surface dressing projects were carried out in 2008 and 2009 in the Nièvre department to measure the product’s application capacity, its durability over time and its acoustic properties.
The first positive point of the trials was actual execution, without major difficulties, on three sites employing a 2/4 single surface dressing or 4/6-2/4 double chip surface dressing. Initial inspections carried out at the beginning of 2010 detected no signs of deterioration. The trials were judged very encouraging on the acoustic level, since the noise levels measured are similar to the results obtained with porous asphalt.
This innovation was awarded a Special Marketing prize in the Materials, Processes and Techniques category.