Which reference standard is used for calculating minimum compaction density after stabilization?

• A. FM 2 T-170
• B. FM 3 T-180
• C. FM 1 T-190
• D. FM 1 T-180

Answer: (D)

When stabilizing soils, you need a standardized way to determine the target density so compaction can be verified consistently in the field. The reference standard used for calculating the minimum compaction density after stabilization is FM 1 T-180 because it provides the procedures for obtaining the stabilized mix’s density targets—including how to determine the maximum dry density and the moisture conditions under which that density is achieved—and then how to translate that into a field density requirement. This ensures the stabilized material is compacted to an adequate level to meet performance expectations.

The other standards cover different materials, stabilization methods, or testing regimes that don’t specify how to compute the minimum density after stabilization, so they aren’t the appropriate reference for this calculation.