Prime (several classes)

Prime (several classes) – Asphalt

Types and grades of bituminous binders


Paveking supplies a number of types and grades of bitumen available in South Africa for use in a wide range of applications such as:

  • Hot and warm mix asphalt;
  • Chip seals;
  • Prime coats;
  • Tack coats;
  • Slurry seals;
  • Micro-surfacing;
  • Stone precoating fluids.


The two most common primes supplied by Paveking and used under normal circumstances are:

  • MC–30cut-back bitumen (SANS 4001-BT2)
  • Inverted bitumen emulsion (SABS 1260, will soon be updated to SANS 4001–BT5)



The function of a prime coat is threefold, namely:

  • Serve as a post treatment curing membrane on chemically stabilized layers.
  • Promote bonding between the seal and the base layer.
  • Prevent uneven permeability on the base layer surface. Note that a prime is not impermeable.



The selection and application of a prime coat should suit its function. There is no reason why a prime coat should penetrate deep into the base layer, other than to form a proper bond with the surface. It is unfounded to use a more volatile prime coat to facilitate quicker penetration, when problems may be experienced with the drying out of the prime coat. This practice is disadvantageous for developing strength in chemically stabilized layers.


With chemically stabilized layers, the prime coat’s function as a post treatment membrane is extremely important for developing strength in the layer. The aim is to cover the base layer as quickly as possible, so that it forms a dense membrane, protecting the base layer from the atmosphere, rain and occasional traffic. This is also important where carbonation of the stabilized material is possible.

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