The land transport system is heavily resource dependent, with raw materials, fossil fuels and energy all being consumed in large quantities. Recycling material reduces impacts on the environment because we don’t need to source as much raw material and can reduce the amount being sent to landfills.
The tables below outline the recycled surface and pavement materials currently allowed on Waka Kotahi projects, according to the relevant specifications. The tables also provide limitations by volume of mass and relevant comments about the use of materials.
Material type | Allowed | % by mass | Comment |
Various | Yes | No restriction |
This Sub-base aggregate guidance provides guidance on developing a local specification for sub-base aggregates. Generally, there is no upper limit for recycled material content. Local specification using recycled material other than glass will need to be approved by the appropriate regional council. |
M4 Specification for basecourse aggregate
Material type | Allowed | % by mass | Comment |
Recycled crushed concrete (RCC) | Yes | No restriction | RCC use must be approved by the appropriate regional council. |
Glenbrook melter slag | Yes | No restriction | Slag use must be approved by the appropriate regional council. |
Reclaimed glass | Yes | 5% |
Proportions of reclaimed glass in excess of 5% may be used at the discretion of Waka Kotahi, provided that the requirements of the T15 Specification for repeated load triaxial (RLT) testing for pavement materials have been satisfied. T15 Specification for repeated load triaxial (RLT) testing for pavement materials |
M6 Specification for sealing chip
Material type | Allowed | % by mass | Comment |
Glenbrook melter slag | Yes | No restriction |
M10 Specification for dense graded asphaltic concrete
Material type | Allowed | % by mass | Comment |
Recycled asphalt pavement (RAP) | Yes | <15% | No restrictions. |
15% - 30% | Needs to meet mixed design requirements. | ||
>30% | Requires approval of the National Pavements Manager (Waka Kotahi NZ Transport Agency). | ||
Coarse recycled aggregate material | Yes | No restriction | Subject to the engineer's approval (includes slag or glass, or other materials approved by the engineer). |