What are the different types of bituminous surfaces?

Updated: Feb 14

Post from: Lochan Yadav

What is Bituminous Road The bituminous road consists of their surface with bituminous materials which is also called as Asphalt. It is a sticky dark viscous liquid obtained from natural deposits like crude petroleum.

Different Types of Bituminous Surfaces

1.Prime Coat :

It is the first application of low viscosity liquid bituminous material over an existing porous surface like WBM base course. The main object of priming is to plug in the capillary voids of the porous surface using a low viscosity binding material. Mainly SC or MC cutbacks are the suitable grades chosen on the porosity of the surface.

Functions :

  • The most important function is to improve the adhesion between the existing previous base and wearing surface.

  • To bind the dust and loose particles together to form a hard and tough surface.

  • It provides a temporary seal to prevent the surface water from penetrating through the surface.


2.Tack Coat :

The application of bituminous material over an existing impervious pavement surface which has already been treated by a prime coat. Tack coat is generally of higher viscosity at the rate of kg/10m2 depends on the type of surface.

Functions:

  • It is provided to improve the adequate bond between the existing impervious base and wearing surface.

3.Seal Coat:

Seal coat is mainly applied on the impervious surface of bituminous pavements as a topcoat. A pre-mixed sand bitumen (hot mix) seal coat is commonly used over the premixed carpet. The main function of the seal coat is to seal against the ingress of water and to develop skid resistance texture.

Functions:

  • To provide a watertight surface.

  • It improves visibility at night and develops a skid-resistant texture.

  • To improve the wearing resistance of an existing road surface.

4.Surface Dressing :

It is the process in which two or more coats of bituminous materials are applied to a prepared base. This coat consists of bituminous binders sprayed on which chipped aggregates are properly rolled.

Functions :

  • It prevents the removal of binding material & prevents the damage of road due to waterproofing effects.

  • Roads can be easily cleaned & washed as it reduces dust nuisance.

  • A smooth surface of the road reduces the wear and tear of tyres.