Colas are specialist manufacturers and applicators of both conventional slurry and micro-surfacing. We offer slurry design services as well as a dedicated fleet of micro-surfacing and slurry trucks.


A slurry consists of a mixture of crusher sand of varying grading, water, a little cement and stable grade bitumen emulsion. The prime function of a slurry seal is to fill the surface voids to prevent further deterioration due to loss of stone through traffic action, or by ingress of water into the base.

A well-designed slurry has the following characteristics:

  1. It has a relatively high bitumen content to enrich open weathered road surfaces
  2. It will not flush or bleed and possess good skid resistance
  3. It is easily applied
  4. Judicious use of a slurry means sound economy in maintenance work and new construction.

Typical applications for slurry seal in maintenance work are:

  1. Texture correction slurry – to render a uniform texture over a road surface with varying texture, before resealing with a chip seal.
  2. As a wearing course over aged, ravelled surface dressings.
  3. As a void filler in the Cape Seal application.
  4. As a stiffer, patching mix for repair of potholes, edge breaks etc.


Colmat Microsurfacing consists of selected crusher dust, Portland Cement, water and modified bitumen emulsion. The resultant mix has quick-set properties. Surfaces laid with Colmat  microsurfacing can usually be trafficked within one to two hours after placing.  The modifications made in the emulsion results in a stiffer, more flexible mix.  Thicker layers can thus be placed with the Colmat microsurfcing system, with a reduced risk of deformation during high temperature conditions. The Colmat microsurfacing system is placed with a fleet of purpose designed machines.

The crusher dust will have to be evaluated by the Colas Technical Department to ensure compatibility with the microsurfacing emulsion.

Colas produce three types of microsurfacing systems.  These are:

  1. Colmat (suitable for placement of overlays)
  2. Colpave (designed for hand application)
  3. Colrut (designed to effectively fill longitudinal rut deformations on roads)

Please contact the Colas South Africa team for more information on the correct micro-surfacing solution for you.