A prime coat is an application of a low viscosity asphalt to a granular base in preparation for an initial layer (or surface course layer) of asphalt. The purpose of the prime coat is; to coat and bond loose material particles on the surface of the base, to harden or toughen the base surface to provide a work platform for construction equipment, to plug capillary voids in the base course surface to prevent migration of moisture, and to provide adhesion between the base course and succeeding asphalt course. After applying the prime coat, it must cure for a minimum of 48-72 hours before asphalt is placed, with no rain in the forecast.
Source ,28 may 2015 )

Spraying prime coat 
Spraying prime coat

 

There are four primary purposes for the application of a prime coat on an aggregate base course;

1-Coat and bond loose material particles on the surface of the base.
2-Harden or toughen the base surface to provide a work platform for construction equipment.
3-Plug capillary voids in the base course surface to prevent migration of moisture.
4-Provide adhesion between the base course and succeeding asphalt course.

 

Prime coat penetrates 
Prime coat penetrates


Flexible pavement vs rigid pavement comparison 

Comments

comments