Surface Course of Flexible Pavement
This is the top layer which comes in contact with traffic. It normally contains the highest quality materials.
It serves to prevent the entrance of excessive quantities of surface water into the underlying base & sub-grade.
Surface Course is Sub-divided into two Layers
A layer in direct contact with traffic loads. It is meant to take the impact of traffic and can be removed and replaced as it becomes worn.
This layer provides the bulk of the Hot Mix Asphalt structure. It’s main purpose is to distribute load. It may compose of one or several HMA sublayers.