Reference Specifications for Civil Engineering Work 2001

Table 7.2 – Minimum density schedule

Location	Minimum relative compaction (standard) (Cohesive soils generally) (see Notes 1, 2, 3, 4)	Minimum density index (Cohesionless soils) (see Notes 1, 5)
Road and structural (other than building) formations including embankments, footpaths, paved areas and shoulders (see Note 6)
(a)  0.3 m below subgrade level	95%	65%
(b)  0.3 m below subgrade level	100%	80%
All other areas e.g. parks
(a)  0.3 m below finished surface level	90%	62%
(b)  0.3 m below finished surface level	95%	65%

Notes:

Field dry density to AS 1289.5.3.1, AS 1289.5.3.5 or AS 1289.5.8.1. If using AS 1289.5.8.1, calibrate the surface moisture-density gauge in accordance with AS 1289.5.8.4 before use.

Standard maximum dry density to AS 1289.5.1.1.

Relative compaction (% of maximum dry density) to AS 1289.5.4.1.

For plastic soils (designated under the unified classifications system as OH CH MH) compact to not less than 92% nor greater than 96% of standard maximum dry density at moisture contents of between 90% and 120% of optimum moisture content.

Density index to AS 1289.5.6.1. Maximum and minimum dry densities to AS 1289.5.5.1.

In the context of this specification, road formation is deemed to include all the area within the designated road reserve. Structural formation is deemed to include the area under the paving plus a nominal 1 m from the edge of the paved area.

Mechanical interlock method of construction

This construction method applies to granular fill. Place and compact coarse granular fill materials uniformly in layers. Roll each layer until no permanent visible lowering of the surface occurs. The minimum thickness of uncompacted layers is 150 mm. Determine the maximum thickness of uncompacted layers from Table 7.3 for the specified module weights, which apply to both drawn and self-propelled single drum rollers. Interpolate layer thickness for module weights between the listed values.