i need of report on flexible pavement in ppf
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A true flexible pavement yields "elastically" to the load of traffic. It is constructed with a bitumen treated surface or a relatively thin surface of hot blend asphalt (HMA) on one or more non-attached base layers resting on a subgrade. Its strength is derived from the load distribution characteristics of a laminate system designed to ultimately protect each underlying layer including subgrade compression failure. Progressively better materials are used in the upper structure to withstand higher near-surface stress conditions caused by traffic wheel loads. These materials include a surface for all types of weather that is resistant to erosion by the environment and the action of traffic. The bituminous surface layer must also be resistant to fatigue damage and stable under traffic loads when pavement temperatures exceed 150 ° F.
In this guide, hot-mix asphalt pavements are a more generalized term used to describe any "black cover" structures outside the HMA superimposed concrete. These pavements are classified as flexible or semi-rigid (to include the complete or perpetual design). This chapter addresses the design of these types of structures. The fundamental difference between a flexible, semi-rigid and rigid pavement is the distribution of the load on the subgrade. The semi-rigid pavement has a composite modulus of elasticity higher than a flexible pavement and begins to resemble the rigid structure as to how the traffic loads are distributed over the subgrade.
A true flexible pavement yields "elastically" to the load of traffic. It is constructed with a bitumen treated surface or a relatively thin surface of hot blend asphalt (HMA) on one or more non-attached base layers resting on a subgrade. Its strength is derived from the load distribution characteristics of a laminate system designed to ultimately protect each underlying layer including the subgrade of the compression-cut failure.
Progressively better materials are used in the upper structure to withstand higher near-surface stress conditions caused by traffic wheel loads. These materials include a surface for all types of weather that is resistant to erosion by the environment and the action of traffic. The bituminous surface layer must also be resistant to fatigue damage and stable under traffic loads when pavement temperatures exceed 150 ° F.
In this guide, hot-mix asphalt pavements are a more generalized term used to describe any "black cover" structures outside the HMA superimposed concrete. These pavements are classified as flexible or semi-rigid (to include the complete or perpetual design).
The fundamental difference between a flexible, semi-rigid and rigid pavement is the distribution of the load on the subgrade. The semi-rigid pavement has a composite modulus of elasticity higher than a flexible pavement and begins to resemble the rigid structure as to how the traffic loads are distributed over the subgrade.