The Utica Office of ATL was selected from hundreds of laboratories certified by the American Association of State Highway and Transportation Officials (AASHTO) Accreditation Program to participate in a study for soil and aggregate testing.

The AASHTO T 180 ILS study was established to determine the precision estimates of AASHTO T 180 for Methods B and D specific to compacting fine- and coarse-grained soil blends in a 6-inch mold.

This study was sponsored by AASHTO, in cooperation with the Federal Highway Administration, and was conducted in the National Cooperative Highway Research Program (NCHRP), which is administered by the Transportation Research Board (TRB) of the National Academies.

The laboratories selected to participate in the study were ranked by scores earned through the accreditation process. Thirty-two laboratories, including commercial, governmental, and research laboratories, were selected to participate in the study.

The approach used for the study design of the ILS was based on ASTM E 691, “Standard Practice for Conducting an Inter-laboratory Study to Determine the Precision of a Test Method”, which required participation of a minimum of 6 laboratories meeting E 691 requirements.

The study involved performing three replicates of each of four materials, which were compacted using a 4.54-kg manually-operated rammer according to AASHTO procedures. Prior to the compaction, specific gravity of the soil-aggregate blends were determined. The specific gravity values were used to calculate the percent moisture that results in 100% saturation of the blends.

ATL was honored to be a part of the nationwide study and to be quality selected to help determine a precision estimate for a major AASHTO method.