In February 2022, AASHTO announced its 2022 Interim Revisions to the Guide Specifications for Highway Construction - 10th Edition. In addition to being AASHTO’s first use of an electronic supplement, the interim revisions included AASTHO’s first diamond grinding specification for pavement preservation.

This specification, patterned after the IGGA’s preservation grinding specification, includes a two-tier approach. For existing pavements below a specified roughness level (threshold), the post grinding smoothness is a fixed value. For existing pavements rougher than the threshold value, the final smoothness level is a percentage of the existing value--specifically, a 40 percent improvement in smoothness. The specification uses the International Roughness Index (IRI) so that more accurate smoothness results can be obtained. This means the same smoothness measurement statistic is used for both construction acceptance and pavement management, allowing a cradle-to-grave smoothness statistic that should enable the development of future smoothness changes and more meaningful incentive/disincentive specifications.

To purchase a copy of the interim specifications, visit the AASHTO store.