Edition 9 | Spring 2021

A Rise in Construction, A Rise in Recycling

With the addition of the Edge Innovate product range (see the press release on page ..), I wanted to share some interesting insights into the amount of waste generated in our most populous city, which also leads the country in construction demand.
Construction & Demolition (C&D) waste is one area where we can recycle spent or leftover materials. The amount generated through building and developing new communities is staggering. For example, Auckland produces over 700k tonnes of C&D waste each year, accounting for roughly 40% of the city's total landfill volume and is growing. Surprisingly, curbside refuse generated by households fills just 15% and, in terms of volume, has stayed steady over the last decade.

C&D Waste is broken up into four key segments:

• Rubble and Concrete – 40%
• Timber – 21%
• Special and Hazardous waste – 36%
• Other waste (e.g. Glass, plastic, paper, metals etc.) – 3%

With Rubble and Concrete making up a large majority of C&D material entering landfill, there is a lot of scope for improvement to prevent it from filling up landfills around the city.

We have been involved in a number of initiatives involving the recycling of concrete and rubble throughout the years, because businesses have seen recycled concretes potential for use.
Once properly processed, crushed concrete produces an excellent basecourse that bonds together quite well, making it an ideal foundation for any project. The recycled concrete binds so well due to the amount of fines and still active cement from the original material.

Even though it has good characteristics as a basecourse, we have observed that many engineers and some contractors are reluctant to use recycled concrete in their projects because they are cautious of materials they are not familiar with.
Recycled concrete is only a 'new' concept to us here in NZ, but not in many other countries, which have been using recycled concrete in construction projects for decades, and in some cases, primarily recycled material. For example, in the 1940s, when reconstructing Route 66 in the Illinois section, contractors recycled the existing pavement and reused it in the new road.
From my experience crushing and using recycled concrete, I can say that it is a more than adequate product and forms a highly durable and easy to work with base. We recently used recycled concrete in the foundation of our new head office and workshop in Masterton, using our own equipment to make it on-site!
In Auckland Transports recently issued a "Specification for infrastructure works for the supply of aggregates", there is now a specification for certified Recycled Crushed Concrete in ATAP40, ATAP65 and ATAP20. This specification should give more contractors and engineers confidence to use recycled concrete in their projects.