Committee D18 on Soil and Rock
Vibrating Hammer Test to Be Used for Soils Field Testing
A new standard recently approved by ASTM International Committee D18 on Soil and Rock is the result of requests from the Indiana Department of Transportation and the U.S. Bureau of Reclamation for an effective test method to cover the determination of the maximum dry unit weight and water content range for effective compaction of granular soils. D 7382, Test Methods for Determination of Maximum Dry Unit Weight and Water Content Range for Effective Compaction of Granular Soils Using a Vibrating Hammer, was developed by Subcommittee D18.03 on Texture, Plasticity and Density Characteristics of Soils.
While other standards work well with nongranular soils, D 7382 is a faster method that provides more accurate maximum unit weight for granular soils. “This test is for establishing the maximum dry unit weight of granular soils where the amount of plastic fines is less than 15 percent or the amount of non-plastic fines is less than 35 percent,” says Vincent Drnevich, professor of civil engineering, Purdue University, and a longtime member of ASTM who has been involved in several D18 subcommittees and currently chairs Task Group D18.08.03 on New Technologies. Drnevich notes that the test provides this value on either oven-dry specimens or in some cases on specimens that are nearly saturated. “Research has shown that the optimal water content for compacting these soils is somewhere between 80 and 100 percent of that to fill the soil voids at maximum dry unit weight,” says Drnevich. “This is a distinct improvement in that a wider range of soils can be used with this test method and it gives a good value for the water content required for effective field compaction of soils.”
Government agencies, state highway departments and consulting firms engaged in laboratory and field testing of soils are among the most likely users of D 7382, according to Drnevich, who says that user feedback will be valuable in developing future revisions to the standard.
“As with nearly all new standards, improvements are likely and will come about with increasing widespread use of the test method,” says Drnevich. “Subcommittee D18.03 would welcome feedback from interested users and future revisions of the standard may be based on user comments.”
Technical Information: Vincent Drnevich, Purdue University, West Lafayette, Ind.
ASTM Staff: Robert Morgan