Pavement Treatment Testing - San Joaquin Road
A 4.3-mile section of San Joaquin Road between Old Ajo Highway and Milky Way Drive has been selected as a testing ground for several pavement treatments.
Treatments will be tested for various factors to ascertain life-cycle return on investment leading to more cost-effective selection of pavement treatments for use in Pima County 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 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. Construction is scheduled for this summer with treatments to include:
- Section 1: 1-inch Green Asphalt overlay with fiber southbound lane only
- Section 2: 1-inch PAG 3 terminal blend overlay
- Section 3: 2-inches PAG 2 overlay
- Section 4: 2-inches PAG 2 with fiber overlay
- Section 5: Pulverize 6-inches existing and compact with double chip seal & fog seal
- Section 6: Pulverize 6-inches existing and compact with single chip seal & micro surface
- Section 7: Pulverize 6-inches existing and compact with single chip seal & fog seal
- Section 8: Pulverize 6-inches existing and compact cement treated (300 psi) with chip seal & rubberized (terminal blend) chip seal & fog seal
- Section 9: Pulverize 6-inches existing and compact cement treated (150 psi) with chip seal & fog seal
- Section 10: 2"-inches PAG 2 mill & fill
- Section 11: Pulverize 6-inches existing and compact cement treated (300 psi) with chip seal & fog seal
- Section 12: 6-inches roller compacted concrete
- Section 13: Double chip seal overlay & fog seal
- Section 14: Rubberized (terminal blend) single chip seal overlay & fog seal
Evaluation of the test treatments are scheduled to occur six months post construction and at annual intervals thereafter. Observations will include: cracking, rutting, oxidation, surface wear and roughness, supplemented by the regional Pima Association of Governments/City of Tucson Automated Road Analyzer van and additional laboratory tests as needed.
Treatment-specific curves will be developed based on data from each evaluation interval to rank treatment benefit-cost projection based on standardized return on investment criteria. These curves will be correlated against longer-term national research data for that treatment type, to infer longer term performance from shorter observation periods. The treatment curves will be controlled to account for minor localized variations in soil or drainage conditions.