RECYCLING OF OLD ASPHALT IN WEARING COURSES OF DENSE ASPHALTIC CONCRETE: DEMONSTRATION PROJECT ALMERE-LELYSTAD

A demonstration project has been carried out on the Dutch state road 6 between Almere and Lelystad, in which 20% milled asphalt has been re-used in a dense asphaltic concrete wearing course. The specification was that the regenerated dense asphaltic concrete had to be at least as good as the dense asphaltic concrete prepared in the conventional way. To determine whether this is so, test pieces have been taken from the demonstration section to be examined for different pavement characteristics. This test showed that the earlier mentioned equality was achieved. Because of the application in wearing courses, the old asphalt must come from binder and wearing courses that contain neither gravel nor other materials that are not suitable for wearing courses. Pressure points when introducing this form of recycling are especially of an economic nature (such as the market value of the milled asphalt, the cost of transport or storage). The acceptance by the commissioner of the work is not very high as yet. A stimulating policy, by Dutch "Rijkswaterstaat" for example, will be necessary to promote the recycling of old asphalt. Drawing up more stringent regulations is a possibility, e.g. by prescribing recycling in wearing courses. (TRRL)