30 June 2001
a. Procedure. The compaction temperature for the bituminous mixture should be as specified
by ASTM D 1561. For the first step in molding specimens, heat the compaction mold to the same
temperature as the mix. Next, place the compaction mold in position in the mold holder and insert
a paper disk 102 millimeters (4 inches) in diameter to cover the baseplate of the mold holder.
Weigh out one-half of the required amount of bituminous mixture for one specimen at the specified
temperature and place uniformly in the insulated feeder trough, which has been preheated to the
compaction temperature for the mixture. By means of the variable transformer controlling the
heater, maintain the compactor foot sufficiently hot to prevent the mixture from adhering to it. By
means of a paddle of suitable dimensions to fit the cross section of the trough, push 30
approximately equal portions of the mixture continuously and uniformly into the mold while 30
tamping blows at a pressure of 1.7 Mpa (250 psi) are applied. Immediately place the remaining
one-half of the mixture uniformly in the feeder trough. Push 30 approximately equal portions of the
mixture into the mold in a continuous and uniform manner while applying tamping blows at a
pressure of 1.7 MPa (250 psi). If sandy or unstable material is involved and there is undue
movement of the mixture under the compactor foot, reduce the compaction temperature and
compactor foot pressure until kneading compaction can be accomplished.
b. Immediately after compaction with the California kneading compactor, apply a static load
to the specimen using a compression testing machine. Apply the load by the double-plunger
method in which metal followers are employed as free-fitting plungers on the top and bottom of the
specimen. Apply the load on the specimen at a rate of 13 millimeters (0.5 inches) per minute until
an applied pressure of 6.9 MPa (1,000 psi) is reached. Release the load immediately. After the
compacted specimen has cooled sufficiently so that it will not deform on handling, remove it from
the mold. Place the specimen on a smooth flat surface and allow to cool to room temperature.
Cylindrical specimens will have approximately the same bulk specific gravity as specimens prepared
as specified by ASTM D 1559 and ASTM D 1561.