Section 4: Special Considerations for the Construction of Perpetual PavementsAnchor: #i1027741
As with any pavement structure, quality begins at the foundation level. These structures must have a uniform, stiff, durable foundation that will adequately support the premium materials placed above. A geotechnical investigation of the underlying soils is essential to establish the appropriate type and level of treatment needed to stabilize the foundation layers. Where adequate treatment of the subgrade is impractical, a high quality granular base, cement-treated base, or other engineered foundation should be used.Anchor: #i1027789
4.2 Other Considerations
Once the placement of hot-mix begins, it is important to consider the overall length of time and seasonal weather conditions that may occur prior to placement of the SMA (surface) lift to ensure surface water is not trapped in the structure through low density joints or segregation. Strict enforcement of density provisions in the applicable HMA specifications and considerations for use of positive drainage (edge drains) should be made. Where scheduling/traffic control plans prevent the SMA surface from being placed for extended periods of time, placement of a seal coat should be considered as an interim driving surface to minimize trapped moisture.
Detailed perpetual pavement design construction considerations are available through this link.