AASHTO T 99-19 PDF Download

The AASHTO T 99-19 standard provides methods for determining the moisture-density relation of soils using a 2.5-kg (5.5-lb) rammer dropped from a height of 305 mm (12 in.). There are four alternate procedures outlined in the standard, each specifying different mold sizes and sieve requirements. Method A and B use a 101.60-mm (4-in.) mold with soil material passing a 4.75-mm (No. 4) sieve. Method C and D use a 152.40-mm (6-in.) mold with soil material passing a 19.0-mm (3/4-in.) sieve.

The test method is applicable to soil mixtures that have 40 percent or less retained on the 4.75-mm (No. 4) sieve for Method A or B, and 30 percent or less retained on the 19.0-mm (3/4-in.) sieve for Method C or D. Material that is retained on these sieves is considered as oversize particles or coarse particles.

If the test specimen contains oversized particles, adjustments must be made in terms of dry density and moisture in accordance with Annex A1 of the standard. If the specified maximum tolerances for oversized particles are exceeded, alternative methods of compaction control should be used.

It is important to note that this standard provides one method for designing and controlling the compaction of soils. This involves using a test fill to determine the required degree of compaction and a specific method to achieve that compaction. The compaction control is then maintained through the specification of compaction equipment type and size, lift thickness, and the number of passes.