pavement surface exhibits depressions as a result of compaction/mix design problems. Sub grade rutting occurs when the sub grade exhibits depressions due to loading. In this case, the pavement settles into the sub grade ruts causing surface depressions.

Fig. 4.4 Rutting in Asphalt ( halifax.ca )

4.5 Uplifts

4.5.1     Uplifting

Because of the weather conditions in Windsor, the soil under the sidewalk expands and contracts during the freeze-thaw cycle. This effect, as well as tree roots, causes sections of the sidewalk to move vertically, creating a trip hazard. This typically occurs along joints or cracks in the sidewalk.

The height of the uplift determines its severity as outlined below:

• Minor Uplifts: less than (but not equal to) 15 mm (0.6 inches) high

• Major Uplifts: greater than or equal to 15 mm (0.6 inches) & less than 20 mm (3/4 inch) high

• Urgent Uplifts: greater than or equal to 20 mm (3/4 inch) high

  For asphalt, these height differentials are used to categorize and record deficiencies as Low Severity, Medium Severity and High Severity respectively, see Section 7.

  If an uplift greater than or equal to 3/4 inch (20 mm) is encountered during an inspection, it is to be spray painted (refer to fig. 4.5.2 for correct painting procedure) to warn pedestrians of its location and then reported to the maintenance crews for a temporary patch job once all sidewalks in that respective (IMS) area have been inspected.

  If an uplift greater than 1.5 inches (38 mm) is encountered during an inspection it is considered “Priority”. I t is also spray painted to warn pedestrians of its location, the “P” will be checked on the inspection