- Arizona Department of Transportation
- Fann Contracting
- Coconino County, Arizona
- Our Role
- 5 miles
- Construction Cost
- $34 million
- New Construction
- 1 year, 6 months
- Rehabilitated roadway enhances safety for 16,000 motorists each day
- Reduction of pothole formation improves travel conditions and protects vehicles from damage
- Doweled PCCP increases pavement lifespan by 60 percent over undoweled PCCP
- New pavement and repairs reduce maintenance costs by 65 percent.
During the winter of 2016-17, the Devil Dog Wash section of Arizona’s Interstate 40 (I-40) west of Williams experienced pavement degradation at an alarming rate. The failure quickly reached crisis proportions, causing tire blowouts and vehicle damage on a daily basis and creating unsafe travel conditions. New potholes developed as soon as others were patched, and repair efforts tripled maintenance costs for the Arizona Department of Transportation (ADOT) Northcentral District by the end of the season.
A key transportation corridor near Flagstaff, I-40 handles more than 6 million vehicles a year, almost a quarter of which are heavy trucks. To restore safe travel on the highway, ADOT contracted Gannett Fleming to develop a long-term solution for the extreme pavement failure. The team designed a solution to use doweled portland cement concrete pavement (PCCP) to reduce the risk of subgrade exposure and improve pavement performance. The approach increases initial pavement life by up to 60 percent and outlasts previous ADOT asphalt overlays by at least 10 years. To provide a new road surface for Devil Dog Wash as quickly as possible, the team created construction documents in 70 calendar days.
The project entailed rehabilitating approximately 5 miles of I-40 in both directions. To avoid exposing saturated subgrade soils on the westbound roadway, the team chose to retain the existing PCC pavement and pave over it. Workers overlaid the pavement with a doweled PCCP section, featuring an asphalt concrete (AC) base wedge varying in thickness to a maximum of 2.1 feet to provide proper superelevation. For the eastbound roadway, where the subgrade was not as saturated as the westbound roadway, the team removed the full depth of existing pavement and completed a full PCCP replacement.
Doweled PCCP uses dowel bars to provide a mechanical connection between pavement slabs without restricting horizontal joint movements, increasing load transfer efficiency by absorbing some of the load in advance. Consequently, there is reduced joint deflection, minimal stress, and less corner cracking in the slab, which extends roadway life. Throughout the project site, the team ensured that roadway drainage was directed away from the subgrade to prevent pothole formation caused by water infiltration. Rehabilitation work included deck improvements to the Devil Dog Wash overpass to extend its service life and new signage, guardrails, and pavement markings to enhance roadway safety.
- Pavement replacement for two 12-foot-wide travel lanes with 14-inch doweled PCCP over 8 inches of aggregate base improves pavement performance
- New 14-inch doweled PCCP with variable depth asphalt concrete base laid over existing PCCP enhances pavement integrity
- Roadway drainage system using underdrains conveys water away from subgrade soil to protect pavement and prevent water infiltration, inhibiting pothole formation
- Modified roadway superelevation rates meet 70-mile-an-hour design guidelines to reduce crash risk
- Rock scaling reduces risk of dangerous rockfall at cut slopes adjacent to the roadway.
- Arizona Transportation Partnering Excellence Award, 2019, Arizona Department of Transportation
- No. 4 Road, 2018, Roads & Bridges, Top 10 Roads