Standard Test Method for Rapid Determination of Percent Compaction

Importancia y uso:

5.1 The rapid method is performed to quickly evaluate percent compaction and variation from optimum water content of soils used in construction without knowing the value of field water content at the time of the test.

5.1.1 Test results are usually determined within 1 to 2 h from the start of the test.

5.1.2 The value of percent compaction obtained using the rapid method will be the same as the percent compaction calculated using dry density values.

5.1.3 The value of the difference between field water content and optimum water content will be approximate, but will be within ±0.1 to 0.2 percentage point of the difference calculated once the field water content is known.

5.2 Test results may be used to determine if the compacted material meets density and water content control values that are specified as a percentage of a standard maximum density and optimum water content such as determined in Method A of Test Methods D698. A three-point compaction curve is used in place of the four- or five-point curve required in Test Methods D698.

5.3 This test method is based on the assumption that a three-point compaction curve is a parabola at the section of the curve close to optimum water content so that the peak point of the curve can be determined mathematically. This assumption results in the major difference between this test method and obtaining the maximum density and optimum water content from a full five-point compaction curve.

5.4 Once the field ovendry water content has been determined in accordance with Test Methods D2216, the values of dry density, dry unit weight, and optimum water content can be calculated (see Note 1).

5.5 This test method can also be used for foundation or borrow area material to compare in-place dry density and unit weight and water content to laboratory maximum dry density and unit weight and optimum water content.

5.6 This test method has the advantage that the maximum density value can be obtained on the same soil excavated during the in-place density test.

Note 1: Since there is no need to immediately determine the water contents of material from the in-place density test or the laboratory compaction points, use of rapid water content determinations such as microwave, direct heat, nuclear, etc., is not needed. However, if desired, the percent compaction and variation from optimum water content may be determined using dry density values based on rapid water content test methods. Using three compaction points and determining the maximum density mathematically would still apply. However, the rapid water content methods may give results that differ from the accepted oven-dried water content values and will lengthen the time of performing this test method.

Note 2: The quality of the results produced by this test method is dependent on the competence of the personnel performing it and the suitability of the equipment and facilities used. Agencies that meet the criteria of Practice D3740 are generally considered capable of competent and objective testing. Users of these test methods are cautioned that compliance with Practice D3740 does not in itself ensure reliable results. Reliable testing depends on many factors; Practice D3740 provides a means of evaluating some of those factors.

Subcomité:

D18.08

Referida por:

D3839-14R19, D7765-18A, F1668-16R22

Volúmen:

04.08

Número ICS:

93.020 (Earth works. Excavations. Foundation construction. Underground works)

Palabras clave:

compaction control; density; field density; field test; moisture control; moisture-density; rapid compaction control; unit weight; water content;