Pavement Maintenance - Cornell Local Roads Program - Cornell ...

Pavement Maintenance
Table 10 - Distresses repaired by selected thin wearing courses
Waterproofs
the pavement
Restores skid
resistance
48 Cornell Local Roads Program
Restores an
oxidized surface
Trues & levels
minor ruts
Sand seal Yes Yes Yes No
Chip seal Yes Yes Yes No
Slurry seal Yes Yes Yes No
Micropaving Yes Yes Yes Up to 3/4"
NovaChip Yes Yes Yes Up to 1/2"
Thin overlay Yes Yes Yes No
Overlays (up to one inch thick) are a type of thin wearing course. Until almost one and a half
inches are placed, there is not a significant strength increase provided by the asphalt concrete
overlay. A thin overlay will not correct minor ruts. Unless a separate true and leveling course is
applied first, traffic will recompact a single lift of asphalt back in the existing ruts. Micropaving
and Novachip, on the other hand, were designed to fill minor ruts.
Sand seal
A sand seal is a layer of asphalt emulsion covered by a layer of fine aggregate (sand). It is not as
durable as a chip seal. Sand seal has an expected lifespan of four to five years, if placed at the
right time, and in the right place.
Chip seal
Also known as a surface treatment, a chip seal is a
layer of asphalt emulsion covered by a layer of
single-sized aggregate. Timing of the construction,
and the weather during construction, have major
influences upon the success or failure of a chip
seal. Chip seals will be discussed in more detail
later in this chapter. Figure 30 shows the proper
spacing between the laying of the emulsion and the
chip spreader during a chip sealing operation.
Figure 30 – Proper spacing of
emulsion and chip spreader