Table 6 Construction requirements of the asphalt-treated permeable base in cold regions

Weather and Site Conditions

• ≥ 10 °C (50 °F) [42]

Plant Mixing

• ≤ 177 °C (350 °F); mixing temperature range is determined based on the viscosity or recommended by asphalt binder supplier

Silo Storage

• ≤ 8 h [45]

• ≤ 2 h [44]

Placement Thickness

• ≤ 10.2 cm (4-in.) ([38, 45], and [42])

• ≥ twice the maximum aggregate size in ATPB [42]

Roller Selection

• Steel-wheeled roller with a weight of 8–10 tons and operated using static mode with no vibration ([37, 45], and [40])

• Pneumatic tire roller is prohibited.

Rolling temperature

• 60–110 °C (140–230 °F) [40]

• Sufficient cool but higher than 43.3 °C (110 °F) [37] or 37.8 °C (100 °F) [38]

Rolling pattern

• Two to four passes and avoid over-rolling

• APWA-WA-LAGSPs [5]: low amplitude oscillatory rolling mode first to seat and static mode to smooth the surfaces; targeted air voids of 15–20% and minimum infiltration rate of 63 mm/min. (150 in./h) tested by ASTM C170.

Inspections

• Elevation, thickness, and smoothness requirements ([37] and [45])

Protections

• Free of contaminations; geotextile fabric can be used to cover the ATPB and maintain its cleanliness [17]

• Traffic is not permitted on the ATPB course [45]

• Traffic is allowed after a 72-h cure [42]

Tack Coat

• Not allowed on the newly-placed and clean ATPB course [5, 40]

• Light tack coat (0.02 gal/yd² residual asphalt) may be used when the ATPB course is dirty [5]