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9. Trench backfill within the public way shall be compacted to a minimum of 95% Relative <br />Maximum Density as determined by AASHTO T99, method D as corrected for oversize by <br />AASHTO T-224. Lifts or layer shall not exceed 24 inches in depth. Compaction shall be <br />.accomplished using mechanical vibrators or impact tampers. Wheel rolling by a truck or <br />backhoe shall not be acceptable. <br />Within streets, alleys, and sidewalks trench backfill shall consist of ~/4"-0 Crushed Base <br />Aggregate or, with prior approval, controlled density fill. Controlled density fill may be <br />required in trenches less than 15" wide or where the Inspector determines mechanical <br />compaction devices are impractical or ineffective. Pea ,gravel shall not be allowed as an <br />option. <br />Controlled density fill (CDF) may be used in trenches crossing a street or alley right-of--way <br />at right angles to the alignment. With prior consent, the Inspector may allow CDF backfill <br />parallel to the right-of--way. Excavated materials shall not be allowed for use as trench <br />backfill except in unimproved portions of the public way. <br />Controlled density fill (CDF), also known as flowable backfill, is a cementious material <br />mixed, transported, and delivered using normal ready mixed concrete operations. CDF is a <br />mixture of cement, aggregates, water, and admixtures such as fly ash proportioned to provide <br />a non-segregating, self consolidating, free-flowing, and hand-excavatable material. CDF <br />is a hardened, dense, non-settling fill that requires no compaction effort. <br />A design mix shall be submitted for review and approval prior to use of CDF. The mixture <br />shall be designed to ensure that the material placed has a 7-day compressive strength of <br />between 50 psi and 150 psi. The compressive strength shall be tested using 4-inch mortar <br />cubes per ASTM C 109. <br />Traffic may temporarily be placed directly upon CDF prior to paving as soon as it has <br />sufficiently hardened so that the surface will withstand traffic or construction equipment <br />loading without deformation. If CDF is used as a temporary surface restoration material, the <br />surface shall be maintained and repaired due to damage by traffic. <br />10. All portland cement concrete used in the replacement of streets, alleys, or sidewalks shall <br />obtain a minimum breaking strength of 3,000 psi in 28 days and conform to sections 212 <br />through 215 of the Standard Specifications. <br />11. All ornamental surfacing shall be replaced "in-kind" to that surfacing removed. <br />12. Where sections of sidewalk are. requested to be removed by the permittee, they shall be <br />removed to the nearest existing score or joint in each direction. <br />13. Where sections of curb or curb and gutter are removed by the permittee, a minimum often <br />Utility & R/W Permit Policy <br />EXhlblt A - 2$ r:\adminord\rules\OOrowrlexa.wpd(09/13/00) <br />