30 June 2001
The thickness of overlay to use would then be 178 millimeters (7 inches).
11. OVERLAYS IN FROST REGIONS. Whenever the subgrade is subject to frost action, the
design will meet the requirements for frost action stated in Chapter 22. The design will conform to
frost requirements for rigid pavements. If subgrade conditions will produce detrimental nonuniform
frost heaving, overlay pavement design will not be considered unless the combined thickness of
overlay and existing pavement is sufficient to prevent substantial freezing of the subgrade.