Resources

The objectives of this project, undertaken 2005/6, were to:

• review the international technical literature on the topic of environmental issues relating to the use of waste and industrial by-products in road construction applications, and
• recommend a set of guidelines to allow road controlling authorities and environmental agencies to determine if various waste or environmental by-products are appropriate for use in road construction.

The international literature shows that the topic of environmental impact is extremely complex and, by necessity, any assessment strategy needs to be relatively conservative for it to be practical, cost effective and reliable. The study has shown that a number of documents that address the issues of hazardous substances and acceptance criteria for contaminants are currently available in New Zealand.

A new assessment process has been suggested as a result of the literature review. It basically involves a three-tier classification system where industrial by-products proposed for road construction applications are deemed to be inert, notifiable or assessable depending on their composition, intended use and track record.

Keywords: assessment, contamination, environmental impact, leaching, materials, recycling, road construction, secondary aggregates, standards, testing