The Glass Packaging Forum said contaminated glass not suitable for recycling into glass products could be used for roading in Auckland where stone is scarce and in regions where the cost of sending glass to centres for recycling is too high.
Glass is used in roading around the world but its use depends on costing methods in road tenders and government policies.
"One option could be to introduce a sustainable procurement policy along the lines of that enacted in California," forum general manager John Webber said.
"The California Bill will require the California Department of Transportation to use recycled aggregates in state paving projects unless it is economically infeasible."
In New Zealand, an amended Transit road specification introduced this year allows for up to 5 per cent of glass cullet to be used in the base course for roading.
The use of glass cullet would provide a local answer for many communities that find the cost of sending glass back to Auckland for processing was too high, said Mr Webber. A cost benefit analysis funded by the forum found that aggregate with glass cullet cost around $2 a tonne more than conventional mineral aggregate.
Glass was not economically viable unless councils included the potential cost of landfilling the glass into the equation.
Sustainable construction targets could incentivise councils, particularly on South Island to use glass cullet in local roads.
Each year the amount of glass packaging being recovered from homes is rising by about 5 per cent, increasing the amount of glass available for recycling.
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