Waste Concrete Recycled


An Auckland demolition company is turning waste concrete into roads – saying this offers cost-savings to road builders, reducing use of non-renewable materials from riverbeds and quarries, and cutting carbon emissions.

Ward Demolition of Onehunga, recycled 96% of the demolition waste from Auckland’s BNZ tower, and 92% from Eden Park Stadium.

“This waste would otherwise have been destined for already overloaded landfills. Much of what we recycled was concrete” says Peter Ward, owner of Ward Demolition. He says independent tests show that recycled crushed concrete exceeds standards for NZ road construction across all road types and conditions – wet or dry.

Ward pops up everywhere around Auckland construction sites

Dr Greg Arnold of Pavespec Ltd,  says it’s the “best result to date for an unbound granular material.”

Ward says that a significant quantity of the CO2 released during cement manufacture has the potential to be chemically reabsorbed by concrete during its life. By breaking concrete into aggregate-sized particles its surface area is increased, raising its capacity to reabsorb CO2.

The recycled crushed concrete is also a sustainable alternative to natural aggregates, meaning that consumption of non-renewable sources such as riverbeds and quarries can be considerably reduced. The construction and demolition industry is one of New Zealand’s largest waste producers, contributing around 17% of waste that is sent to landfill. Concrete represents approximately 30% of this amount.




  1. Jeremy Harris says:

    Awesome idea…

  2. ingolfson says:

    Most interesting is the fact that they wouldn’t be doing it if it wasn’t cost effective. There is no subsidy to do it that I am aware of (though it may get you points in Green building certification), so the combination of new material cost & landfill costs is now high enough for this to make sense. No reason then why it shouldn’t become pretty much standard.

  3. Joshua says:

    ingolfson - as far as I know it already is in bigger projects, the new thing here is it’s a demolition company selling the recycled material, I know on big roading projects this technique has been used for a long time to reduce cost of importing material.

    However good on them, it was only a matter of time before the costs of crushing and exporting the material would become economic enough to compete with extracting material from quarries.


Leave a Comment


XHTML: You can use these tags:
<a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <cite> <code> <del datetime=""> <em> <i> <q cite=""> <strike> <strong>