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I <br /> I <br /> GEOTECHNICAL EVALUATION <br /> EVERETT, WASHINGTON <br /> February 6,2018 <br /> 1 We recommend that, at a minimum, 12 inches of the existing subgrade material be moisture conditioned <br /> (as necessary) and re-compacted to prepare for the construction of pavement sections. Deeper levels of <br /> I recompaction or overexcavation and replacement may be necessary in areas where fill and/or loose soils <br /> are present. Deeper excavations should be expected if earthwork occurs outside of the dry season <br /> (generally June through September). <br /> I <br /> The subgrade should be compacted to at least 95 percent of the maximum dry density as determined by <br /> ASTM Test Method D1557. In place density tests should be performed to verify proper moisture content <br /> and adequate compaction. However, if the subgrade soil consists of firm and unyielding native glacial <br /> I soils a proof roll of the pavement subgrade soil may be performed in lieu of compaction tests. <br /> The recommended flexible and rigid pavement sections are based on design CBR and modulus of <br /> subgrade reaction (k)values that are achieved, only following proper subgrade preparation. It should be <br /> I noted that subgrade soils that have relatively high silt contents will likely be highly sensitive to moisture <br /> conditions. The subgrade strength and performance characteristics of a silty subgrade material may be <br /> dramatically reduced if this material becomes wet. <br /> I <br /> Based on our knowledge of the proposed project,we expect the traffic to range from light duty(passenger <br /> automobiles) to heavy duty (delivery trucks). The following tables show the recommended pavement <br /> sections for light duty and heavy duty use. <br /> IASPHALTIC CONCRETE(FLEXIBLE)PAVEMENT <br /> LIGHT DUTY <br /> 1 Asphaltic Concrete Aggregate Base* Compacted Subgrade*** <br /> I <br /> I2.0 in. 6.0 in. 12.0 in. <br /> *95%compaction based on ASTM Test Method D1557 <br /> I **A proof roll may be performed in lieu of in place density tests <br /> HEAVY DUTY <br /> IAsphaltic Concrete Aggregate Base* Compacted Subgrade*** <br /> 3.o in. 6.o in. 12.o in. <br /> I *95%compaction based on ASTM Test Method D1557 <br /> **A proof roll may be performed in lieu of in place density tests <br /> I <br /> I <br /> 1 8 <br /> PO Box 82243 <br /> Kenmore,WA 98028 <br /> (206)331-1097 <br /> ICobaltgeo 1gmail.com <br />