Asphaltic Concrete

Asphaltic Concrete, sometimes referred to as bitumen macadam, is a mixture of aggregate, filler dust and bitumen and can be dense, medium or open graded depending on the application. Asphalt concretes can be classified into three different layer categories:

1. Base – the main load-bearing/load-spreading layer in the road structure and is usually 100mm, although can be thicker depending on the loading of the traffic for which the road is designed.
2. Binder – a load-spreading layer, spreading the load imposed on the WEARING COURSE (surface course) over a wider area of the ROADBASE (base).
3. Surface – the top layer of the ROAD  PAVEMENT and as such is (usually, but not always) designed to be impervious to the ingress of water, have an even RUNNING SURFACE, be durable, and have a high resistance to skidding and be chosen so as not to deform under the weight of traffic appropriate to the road.