Table of Contents

3.3 Sprayed Seal (Secondary and Retreatments)

A sprayed seal is formed by the spraying of binder and covering it with a layer of aggregate. It may contain more than one application of binder and/or aggregate.

In New Zealand, the term ‘chipseal’ is used. ‘Chip’ refers to the description of the aggregate particles used in sealing work.

Depending on the application and type of seal, a sprayed seal may be used as an initial seal, secondary treatment, or retreatment, as defined in Section 3.1.

A ‘reseal’ is the term used to describe the application of a sprayed seal over an existing bituminous surface (e.g. a seal, asphalt or slurry surface).

Multiple application seals are generally described in a sequence of the application of binder and aggregate, for example:

  • double/double = two applications of binder and two applications of aggregate
  • single/double = a single application of binder and two applications of aggregate.

Special-purpose treatments are also used to meet specific circumstances and include single/single seal with scatter coat, dry matting, inverted seal, high-stress seal, strain alleviating membrane, strain alleviating membrane interlayer, fibre reinforced seal, geotextile reinforced seal and cape seal. Salt‑affected pavements also require special consideration.