Broken bottles and shattered glass. Warped plastic and disheveled cardboard. A global mountain range peaking with over-consumption. What once featured as an indefinite product of exportation is now coming to a halt, as the Australian Government poses a ban on waste exportation commencing in 2020.

Fifty-eight percent of the waste Australia generates is recycled domestically. The remaining is shipped overseas with China being the largest export market for recycled waste. Your used pasta sauce jars and thirst-quenching bottles of beer are not exempt, of all the waste glass exported, 79% is sent to Malaysia. However, as of November 8, 2019, recycling as we know it, will be the nation’s responsibility. At the Meeting of Environment Ministers the following timeline to ban waste export with a phased approach was determined:

• All waste glass by July 2020
• Mixed waste plastics by July 2021
• All whole tyres including baled tyres by December 2021
• Remaining waste products, including mixed paper and cardboard, by no later than 30 June 2022.

Under the agreement, waste items that have not been processed into a “value-added” material – for example, items that can be used in the manufacture of other products – would be subject to the ban.

Taking on the challenge to reduce and prevent stockpiling of waste glass in Australia’s warehouses is researches from James Cook University (JCU), turning what may be seen as an unsustainable situation into a viable market. Working with Cairns Regional Council and Pioneer North Queensland Concrete, the scientists found that finely crushed glass can be used as a replacement for sand in concrete.

Turning a temporary solution of waste storage into a sustainable, environmental and cost-effective outcome, Associate Professor Rabin Tuladhar states “The research showed that replacing up to 40% of natural sand with waste glass could improve the strength and durability of concrete”. When waste glass is crushed to sand-like particle sizes, similar to those of natural sand, it exhibits properties of aggregate material. It is particularly useful in highway construction as an aggregate substitute in asphalt paving.

A potential delay in using waste glass in the concrete industry was the concern of a reaction between silica in glass and alkali in concrete, causing the concrete to crack. However, testing undertaken by JCU’s researchers revealed the contaminants in waste glass such as paper and organic materials including sugar contribute to the reaction but can primarily be removed by washing the glass and using modern glass crushing facilities.

“Our research showed that when glass is crushed to the fineness of sand or cement it, in fact, reduces this reaction and further contributes to concrete strength.

“We also found if we pulverised waste glass to cement fineness, it develops binding properties and can be used to replace up to 10% of cement in concrete,” said Dr. Tuladhar.

With confidence Australia’s waste stockpiles can be effectively used in construction products, the team is working with Townsville City Council, the Waste Management company and local concrete companies to secure funding for a large-scale trial using crushed waste glass in concrete.

As the ban on exportation solidifies, locally stored glass of sufficient size will be accumulated, providing a consistent supply that can be used as a substitute for natural sand, in pavement construction applications and non-structural concrete such as drainage pits and culverts.

The Australasian Pozzolan Association is encouraging beneficiation of what was once considered waste material exported overseas, into the value-added resource to be used in the construction materials sector. Developing sustainable value-added applications is not without its challenges. The Association is working closely with Standards Australia to establish new specifications and requirements to create confidence for these merging resources.  Want to get involved?  Get in touch with the Association today.