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  • Transportation Department to test asphalt materials on San Joaquin Road

    May 01, 2018 | Read More News
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    Pima County Department of Transportation has selected a 4.3-mile section of San Joaquin Road between Old Ajo Highway and Milky Way Drive as a testing ground for several asphalt treatments. 

    The 12 different pavement treatments selected will be tested for strength, durability and longevity. Testing also will serve to evaluate the costs of each treatment to determine the most cost‐effective pavement treatments.testing

    The treatments will be laid in multiple 1,000-foot test sections covering both directions of traffic. Pima County will group the treatments by color and texture over a 12,000 segment of the roadway to minimize the visual patchwork. The balance of the roadway will be repaved by removing 2 inches of existing asphalt and replacing it with 2 inches of traditional asphalt.  The result will be the complete repair of a 4.3-mile section of roadway that has fallen into poor condition. 

    The Department will evaluate the wear to test segments every six months, and forecast performance each treatment over time. The County will also study the road over several years to determine the best, most cost-effective and long-term treatment options. The segments will be installed this summer. 

    The sample treatment materials chosen include: 
    • 1 inch green asphalt over existing
    • 2 inches overlay of existing PAG 2 mix (PAG 2 is the most common asphalt mixed used in the metro region)
    • 2 inches overlay of existing PAG 2 mix with terminal blend (terminal blend is asphalt mix blended with dissolved rubber)
    • 1 ¼ inches overlay of existing with PAG 3 Terminal Blend (PAG 3 is a smoother and finer version of PAG 2)
    • 2 inches overlay of existing PAG 2 mix with fiber
    • Pulverize 5 inches and compact with cape seal (chip seal plus slurry seal)
    • Pulverize 5 inches and compact with chip seal
    • Pulverize 5 inches and compact with cement (300 psi) and chip seal
    • Pulverize 5 inches and compact with cement (500 psi) and chip seal
    • 6 inches roller-compacted concrete
    • Double chip seal over existing surface
    • Rubberized chip seal over existing
    As the Department of Transportation moves forward with its pavement repair and preservation program, partially funded through a 25-cent primary property tax dedicated to road repairs, the County is working to modernize the maintenance of the transportation network using a data-driven approach to ensure better overall transportation network management and enhanced service delivery at a lower cost.