Currently, a SDDOT construction inspector is required to make a one-point proctor test for each of the in-place specified density tests. The inspector must return to the field lab to complete the one-point proctor test. The one-point proctor results are then compared to the family of curves from the Ohio Typical Moisture Density Curves to determine the target Maximum Dry Density. This is a time-consuming process, removing the inspector from the project for an extended period of time. Often, a large quantity of embankment is placed before the results of the tests are determined. If the test fails, a substantial amount of rework by the Contractor can be incurred.
A review of current procedures to improve inspector efficiency while maintaining quality is needed. A review of Federal agency and surrounding state DOT practices is desirable to assess existing ways to improve our current procedures and policies. The necessary level of training required will need to be addressed, if more efficient procedures are identified. Increased inspector efficiency and improved testing methods will not only improve contractor efficiency but will minimize construction delays due to testing. Although, significant advances in moisture/density testing of soils has not occurred in recent years, improvements have been made in procedures and use of existing equipment such as nuclear density gauges and microwave ovens for moisture determination.
The purpose of this research is to increase the efficiency of our test methods, not to change the specification of the amount of compaction required. We are confident that our current specification (95% + of Maximum Dry Density in most cases) is in line with standard practices.