Depth in inches below
Subgrade Level Percent of AASHTO T-180 (Method-D)
Maximum Dry Density
00 – 12 95%
12 – 30 93%
More than 30 90%

(iii) In place density determinations of the compacted layers shall be made in accordance with AASHTO T-191 or other approved methods. For all soils, with the exception of rock fill materials, containing more than 10% oversize particles (retained on 3/4 inch), the in-place density thus obtained shall be adjusted to account for such oversize particles as directed by the Engineer. Subsequent layers shall not be placed and compacted unless the previous layer has been properly compacted and accepted by the Engineer.
(iv) Material for embankment at points inaccessible to normal compaction equipment shall be placed in horizontal layers of loose material not more than 8 inches thick and compacted to the densities specified above by the use of mechanical tampers, or other appropriate equipment.
(v) The compaction of the embankment shall be carried out at the designated moisture content consistent with the available compacting equipment. In forming the embankment. The Contractor shall take steps to ensure that the Work can be drained free of rain water, and he shall make due allowance in the height and width of the Work for swelling or shrinkage.
(vi) Embankment material that does not contain sufficient moisture to obtain the required compaction shall be given additional moisture by means of approved sprinklers and mixing. Material containing more than the amount of moisture necessary to obtain the required compaction may not, without written approval of the Engineer, be incorporated in the embankment until it has been sufficiently dried out. The drying of wet material may be expedited by dispersing or other approved methods.
(vii) When materials of widely divergent characteristics, such as clay and chalk or sand, drawn from different sources, are to be used in the embankment they shall be depoSited in alternate layers of the same material over the full width of the embankment to depths approved by the Engineer. Rock, clay or other material shall be broken up, and no accumulation of lumps or boulders in the embankment will be permitted. No surplus material shall be permitted to be left at the toe of the embankment or at the top of cut Sections.