This report documents the construction of three special pavement test sections on I-90 east of Spokane, Washington. The test sections included ultra-thin and thin whitetopping, Modified Class D open graded asphalt concrete, and micro/macro
surfacing treatment. The majority of the project was built with a Superpave Class ½ inch mix. The test sections were built to assess their potential as mitigation measures for studded tire wear.
Final results after five plus years of monitoring indicate the micro/macro surfacing has a very short service life, the Modified Class D HMA has a slightly shorter service life than the Superpave Class ½ Inch HMA, and that the whitetopping sections had the longest service life. However, the ultrathin whitetopping (3-inch) failed due to cracking within a very short period. None of the treatments provided a long-term solution for studded tire wear.
Cost/benefit considerations would point to the Superpave Class 1/2 Inch as the most cost effective choice for this section of I-90.