Published: Jan 2011
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A. PURPOSE AND USE OF LABORATORY COMPACTION TESTS The ASTM test methods for compaction are used to develop a laboratory-derived standard reference density that is used to determine the percentage of compaction and deviation from the optimum water content that is measured by the field in-place density tests. The ASTM Standard Test Methods used for determining compaction characteristics of soil are D698, D1557, D558, D4253, and D4254. These test methods are performed in the laboratory on samples obtained from the borrow area and are used to establish specimen compaction requirements for engineering property testing. The compaction test methods are also periodically performed in the field as construction proceeds to account for variations in soil types and to verify the previously run laboratory standard reference densities.
In general, the impact methods of compaction (ASTM D698 and D1557) are useful for evaluating soils with a percent fines ranging from 5 % to 95 %. The impact methods of compaction testing are typically used as an evaluation standard on fine-grained soils including silty sand, sandy silt, clay silt, silty clay, and clay soils. Because it is difficult to obtain a well-defined moisture density curve for most cohesionless, free-draining soils, an alternative method of density evaluation using minimum (ASTM D4254) and maximum (ASTM D4253) relative density methods was developed using a vibratory table. The relative density test methods are applicable to cohesionless soils with a percent fines ranging from 5% to 15% and a maximum particle size passing the 3-in. sieve. The relative density method of compaction is typically used as an evaluation standard for select sand, gravel, and other free-draining materials.
As indicated by the range of the percent fines provided above, there is some overlap in the use of compaction test methods for soils used in construction. The selection of the most applicable method for the design and field quality control is best determined by the design engineer on the basis of a careful consideration of the required soil performance properties and the practical use of the test methods in the field. The following sections provide an explanation of how the results of compaction tests are used in the design and construction of earth fills.