Kingscote Streets Upgrades - Kangaroo Island Council

Once an area or lot has been proof rolled and accepted by the Superintendent, any damage to the
subgrade due to weather or the Contractor’s activities shall be the responsibility of the Contractor.
No further payment will be made for the repair of soft spots as a result of such damage.
5.1.5 Protection of the Subgrade
Immediately following approval of the subgrade the Contractor shall commence construction of the
pavement to protect the subgrade from moisture from inclement weather and/or construction traffic.
5.1.6 Subgrade Remediation
Where directed by the Superintendent, the Contractor shall carry out remedial works to the affected
areas as directed by the Superintendent:
In confined areas where movement is detected, the Contractor shall remove the suspect subgrade
to the depth nominated by the Superintendent and replace and compact with quarry waste
(PM3/55), screened quarry rubble (PM2/20) or stockpiled pavement material as directed.
In larger areas, the Contractor shall remove the suspect subgrade to the depth nominated by the
Superintendent and backfill using rock ballast (RB65/RB100) rolled to provide a tight, compact
working platform, to enable construction of the pavement layers as specified elsewhere.
5.2 Quality Requirements – Subgrade Preparation
5.2.1 Inspections
The following Hold Points are required during the subgrade preparation:
H-SG1
5.2.2 Quality Testing
Approval and proof roll prior of the subgrade, prior to commencing pavement
construction.
The Contractor shall undertake testing of the subgrade at the following minimum frequency:
Table 5.1
Quality Testing Requirements for Subgrade Preparation
Item Test type Minimum Testing Frequency
Subgrade Field Dry Density 1 per 300 m 2 or min of 3
Maximum Dry Density
Optimum Moisture Content
1 per material type
1 per material type
Level of finished Subgrade Verification Survey 20 m Chainages
The following test procedures shall be as detailed in the granular pavement section of this
specification.
5.2.3 Tolerances
Construction tolerances on each finished granular pavement layer are as follows:
Table 5.2
Item
Finished level of subgrade
Field Dry Density
Field Moisture content
Tolerances on Subgrade Preparation
Tolerance
As detailed in the pavement design
Not Applicable
-10% + 3% of specified moisture
Ref No. 20120236SA1 Kingscote Streets Upgrades Technical Specification 23