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D. Haunching 1. Proper haunching provides a major portion of the pipes strength and stability therefore care must be exercised in insure placement and compaction of the embedment material in the haunches. For larger diameter pipes ( >30 ") embedment materials should be worked under the haunches by hand. Haunching materials may be Class I, II, or III and must be placed and compacted in 8" maximum lifts, compacted to 90% standard proctor density. E. Initial Backfill: 1. Initial backfill materials are required to a minimum of the pipe diameter for proper structural performance of the pipe. The ASTM specifications extend the initial backfill from the springline to 6 " -12" above the pipe to provide protection for the pipe from construction operations during placement of the final backfill and protect the pipe form stones or cobbles in the final backfill. For proper structural performance of the pipe, the initial backfill need only extend to the pipe diameter. Class I, II, or III materials may be used as initial backfill however: a. Class I materials must be used in wet trenches if Class I bedding and haunching materials are used. b. Class II materials must be compacted in 6" lifts to 90% standard proctor density. C. Class III materials must be compacted in 6" lifts to 90% standard proctor density. F. Final Backfill: 1. Final backfill may be Class I, II, or III and must be placed and compacted in 12" maximum lifts and compacted to a minimum of 85% standard proctor density to prevent excessive settlement at the surface. 2.02 SUBMITTALS A. The Contractor shall furnish the Engineer, for approval, a representative sample of fill material obtained from on -site sources at least ten calendar days prior to the date of anticipated use of such material. B. For each material obtained from other than on -site sources, the Contractor shall notify the Engineer of the source of the material and shall 17106 02221 -5 05 -5564