Section 4: Special Considerations for the Construction of Perpetual PavementsAnchor: #i1074761
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. To establish the appropriate type and level of stabilization according to established test procedures, a geotechnical investigation of the underlying soils should be performed. Where stabilization of the subgrade is impractical, a high quality granualar base, cement-treated base, or other engineered foundation should be used.Anchor: #i1074797
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 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.
Construction considerations by layer are summarized in Generalized Perpetual Pavement Design Construction Considerations.”