<p><p><strong>References:<br></strong><em>Avalle and Grounds (2004)<br>Avsar et al. (2006)<br>Clegg and Berrangé (1971)<br>Jumo and Geldenhuys (2004)<br>Landpac (2008b)<br>Scott and Suto (2007)</em></p><p><strong>Method Summary</strong></p><p>Moisture and dry density tests can be performed using a variety of test methods, e.g., sand cone (ASTM D1556 or AASHTO T191), rubber balloon (ASTM D2167 or AASHTO T205), test pit sand replacement (ASTM D4914), test pit water replacement (ASTM D5030), nuclear gauges (ASTM D6938 or AASHTO T310), and drive cores (ASTM D2937). A field test requires a reference laboratory test (e.g., Proctor or relative density tests) to measure the in-situ relative compaction. Moisture content plays a key role in soil compaction for many materials and it is important to know the moisture content-applied energy-density relationship from laboratory testing to predict field compaction. Many of the in-situ density test methods are not applicable if large rocks are present. Use of moisture and density testing before and after IR compaction is documented in the key references listed above. Avalle and Grounds (2004) reported field problems with density results on sites with oversized particles.</p><p><strong>Accuracy and Precision</strong></p><p>ASTM standards for sand cone, rubber balloon, test pit sand replacement, and test pit water replacement methods indicate that the precision could not be determined due to the nature of the test methods. Based on repeatability measurements from a single operator, ASTM D6938 reports a standard deviation for wet density measurements as 0.3 to 1.2 lb/ft³ and for moisture content as 0.3 to 0.5% depending on the soil type and test method used (direct transmission or back scatter). For all the test methods, the accuracy of the test methods was not reported as a standard reference value was not available for comparison.</p><p><strong> </strong><strong>Adequacy of Coverage</strong></p><p>The tests represent material characteristics within about 0.3 meters of the test surface. Typical earthwork specifications require one test per 1,000 to 10,000 yd³.</p><p><em> </em><strong>Implementation Requirements </strong></p><p>The operation requires some training and experience. Use of nuclear gauges pose regulatory constraints and require specialized training by the manufacturer and local environmental agencies.</p><p><strong>General Comments</strong></p><p>Moisture-density testing is widely used in earthwork construction QC/QA practice. However, this testing has limitations especially on projects with oversized particles and variable fill material. Further, moisture-density tests cannot be easily related to strength and stiffness properties of soil (which are used in design). Soil strength or stiffness properties are heavily influenced by the underlying layer support conditions.</p></p>