Evaluation of Modern Compaction Equipment and Visual QA/QC Procedures for Compaction Monitoring

Project Summary

Excessive settlement of embankments constructed of compacted fill has been a recurring problem and may be increasing in frequency. Current quality control standards for Type B MR-90 compaction are based on visual inspection. The quality of the visual inspection process varies with the inspector and the type of compaction equipment used.

Confirmation that the soil water content is within the specified range is also problematic when visual methods are used. It is therefore possible for a soil to be compacted to the required density with a large amount of mechanical effort for a water content below the specified range. This condition may result in significant strength loss when the soil becomes saturated.

The effectiveness of the Type B MR-90 specification is being evaluated by retrieving samples from fills compacted to the Type B specification and determining their relative compaction. If the compaction measurements are determined to be excessively variable, recommendations for alternative QA/QC procedures will be made.