Gyratory Compactors

1).Description:

These Standards specify the method for compaction of cylindrical specimens of bituminous mixtures using a gyratory compactor. Such compaction is achieved by combining a rotary shearing action and a vertical resultant force applied by a mechanical head. This Standard applies to bituminous mixtures (both those made up in laboratory and those resulting from work site sampling), with an upper aggregate size not larger than 37.5 mm.

2).Principle:

During operation the bituminous mixture is contained within a cylindrical mould limited by inserts and kept at a constant temperature within specified tolerances throughout the whole duration of the test. Compaction is achieved by the simultaneous action of a low static compression, and of the shearing action resulting of the motion of the centreline of the test piece, which generates a conical surface of revolution, while the ends of the test piece remain approximately perpendicular to the axis of the conical surface.