Gap graded asphalt is widely used in Britain where it is known as Hot Rolled Asphalt Concrete . It’s also popular within South Africa. In certain areas Gap graded combine is recognized as stone filled sheet asphalt. It’s utilized hot however is usually easier to compact.
On greatly trafficked and high speed highways it requires precoated aggregate rolled in to the surface, following dispersing, to provide skid level of resistance. Gap graded blend relies to some huge extent on the rigidity with the sand/filler/bitumen mortar with regard to stableness. Gap graded mix is sometimes used for surfacing residential streets and car parks in order to satisfy the desire for a very smooth surface look. Skid resistance of the fine distinctive surface can be adequate at lower speeds. Durability of gap graded combines employed for this particular purpose could possibly be improved together with higher deliberation over mix design.
Mix composition the the blend,
By Weight %:
Coarse Aggregate = 30
Fine Aggregate = 53
Filler = 9
Bitumen = 8
By Volume %
Coarse Aggregate = 25.7
Fine Aggregate = 46.0
Filler = 7.8
Bitumen = 17.5
Air Voids = 3.0