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CORNERSTONE <br />EARTH GROUP <br />should have sufficient fines. Samples of potential import sources should be delivered to our <br />office at least 10 days prior to the desired import start date. Information regarding the import <br />source should be provided, such as any site geotechnical reports. If the material will be derived <br />from an excavation rather than a stockpile, potholes will likely be required to collect samples <br />from throughout the depth of the planned cut that will be imported. At a minimum, laboratory <br />testing will include PI tests. Material data sheets for select fill materials (Class 2 aggregate <br />base, '/<-inch crushed rock, quarry fines, etc.) listing current laboratory testing data (not older <br />than 6 months from the import date) may be provided for our review without providing a sample. <br />If current data is not available, specification testing will need to be completed prior to approval. <br />Environmental and soil corrosion characterization should also be considered by the project team <br />prior to acceptance. Suitable environmental laboratory data to the planned import quantity <br />should be provided to the project environmental consultant; additional laboratory testing may be <br />required based on the project environmental consultant's review. The potential import source <br />should also not be more corrosive than the on-site soils, based on pH, saturated resistivity, and <br />soluble sulfate and chloride testing. <br />6.7 COMPACTION REQUIREMENTS <br />All fills, and subgrade areas where fill, slabs-on-grade, and pavements are planned, should be <br />placed in loose lifts 8 inches thick or less and compacted in accordance with ASTM D1557 <br />(latest version) requirements as shown in the table below. In general, clayey/silty soils should <br />be compacted with sheepsfoot equipment and sandy/gravelly soils with vibratory equipment; <br />open-graded materials such as crushed rock should be placed in lifts no thicker than 18 inches <br />consolidated in place with vibratory equipment. Each lift of fill and all subgrade should be firm <br />and unyielding under construction equipment loading in addition to meeting the compaction <br />requirements to be approved. <br />Table 4: Compaction Requirements <br /> <br />Description <br />Material Description Minimum Relative' <br />Compaction (percent) Moisture' Content <br />(percent) <br />Gene21 Fill (within upper 5 ft) On-Site Soils 90 Optimum +/-2 <br />General Fill (below 5 ft) On-Site Soils 93 Optimum+/-2 <br />Trench Backfill On-Site Soils 90 Opfimum+/-2 <br />Trench Backfill (upper 6 inches of <br />subgrade) On-Site Soils 95 Optimum+/-2 <br />Crushed Rock Fill '/.-inch Clean Crushed Rock Consolidate In-Place NA <br />Non-Expansive Fill Imported Non-Expansive Fill 90 Optimum+/-2 <br />Flatwork subgrade On-Site Soils 90 Optimum to +2 <br />Flatwork Aggregate Base Class 2 Aggregate Base' 90 Optimum <br />Pavement subgrade On-Site Soils 95 Optimum to +2 <br />Pavement Aggregate Base Class 2 Aggregate Base' 95 Optimum <br />Asphalt Concrete Asphalt Concrete 95 (Marshall) NA <br />1 -Relative compaction based on maximum density determined by ASTM D1557 (latest version) <br />2 -Moisture content based on optimum moisture content determined by ASTM D1557 (latest version) <br />3 -Class 2 aggregate base shall conform to Caltrans Standard Specifications, latest edition, except that the relative compaction <br />should be determined by ASTM D1557 (latest version) <br />Ponderosa Active Adult Community Page 15 <br />132-2-1 <br />