AASHTO T 180:2021 Standard Method of Test for Moisture- -Density Relations of Soils Using a 4.54-kg (1 0-lb) Rammer and a 457-mm (18-in.) Drop.
3.1.2. Molds having a volume of 0.002124 ± 0.000025 m3 (0.0750 ± 0.0009 ft3) shall have an inside diameter of 152.40±0.70 mm (6.000 ± 0.026 in.) and a height of 116.40 ± 0.50 mm (4.584 ± 0.0 18 in.) (Figure 2). Determine mold volume in accordance with the “Calibration of Measure” section of T 19M/T 19 tbr Unit Mass of Aggregate.
3.1 .3. Alternate types of mold assemblies with volumes that meet the requirements of Sections 3.1.1 and
3.1.2 may be used. Alternate types of mold assemblies must be constructed of a rigid, inflexible material; must not deform during compaction; and be cylindrical with a detachable collar and detachable base plate as described in Section 3.1. The volume of alternative types of mold assemblies shall he determined and verified in accordance with the “Calibration of Measure” section of T 19M/T 19 for Unit Mass of Aggregate as is required in Sections 3.1.1 and 3.1.2. When alternate mold types are first used they should be tested on several different soils types and the results compared to tests results from mold types specified in Sections 3.1 .1.. 3.1.2 and Figures I and 2. Alternative molds are acceptable when test results meet the single operator repeatability limits of this standard.
Note 2—The mechanical rammer apparatus shall be calibrated with several soil types and the mass of the rammer adjusted. if necessary, to give the same moisture—density results as with the manually operated rammer.
It may be impractical to adjust the mechanical apparatus so the free fall is 457 mm (18 in.) each time the rammer is dropped, as with the manually operated rammer. To make the adjustment of free fall, the portion of loose soil to receive the initial blow should be slightly compressed with the rammer to establish the point of impact from which the 457-mm (1 -in.) drop is determined; subsequent blows on the layer of soil being compacted may all be applied by dropping the rammer from a height of 457 mm (18 in.) above the initial-setting elevation, or when the mechanical apparatus is designed with a height adjustment for each blow, all subsequent blows should have a rammer free fall of 457 mm (18 in.) measured from the elevation of the soil as compacted by the previous blow. A more detailed calibration procedure for laboratory mechanical rammer soil compactors can be found in ASTM D2168.AASHTO T 180 pdf download.