Concrete products are made from a combination of cement, water and aggregate material.
The most common aggregates used in concrete are gravel, sand and crushed rock. These materials are necessary for the concrete to achieve its required strength properties.
Aggregates are sourced from local stone suppliers, who mine the raw stone material from quarries. As concrete production surges, so too does the demand for aggregate material, leading to the depletion of finite natural resources.
An alternative solution
So what other materials can be used as substitutes for natural stone aggregates? One answer is somewhat unexpected, but is proven to work: recycled soft plastics.
SVC has established a partnership with the team behind Polyrok, a product that provides a sustainable, environment-friendly replacement for mineral aggregates. Born from the compelling need to find a solution for problematic soft plastic waste, Polyrok is an innovative, functional product that contributes to a circular economy.
Polyrok is made using post-consumer grade soft plastic waste, collected from organisations such as REDcycle and Cleanaway. It has the potential to become a large-scale solution for the safe disposal of harmful soft plastics, while simultaneously reducing the construction industry’s reliance on stone aggregates.
Compared to traditional stone aggregates, Polyrok is lighter, more thermally efficient, and easier to transport. Made from everyday waste items such as cling wrap, plastic bags and food wrappers, Polyrok’s final form is a twisted, rock-like shape, which bonds extremely well to concrete.
Effective disposal of soft plastic waste
Four million pieces of soft plastic waste are collected in Australia through the REDcycle program every single day. Due to the levels of contamination present, this type of plastic is incredibly difficult to recycle, and the majority often ends up buried in landfill or dumped into the ocean, where harmful toxins can leach into the environment as the plastic degrades over time.
The conversion of soft plastic waste into recycled plastic aggregate offers a promising solution. When Polyrok is used within concrete, it is locked away from the natural environment, tightly bound in its concrete enclosure, and doesn’t degrade. Furthermore, when the concrete product reaches the end of its lifespan and is crushed for recycling purposes, the Polyrok aggregate can be easily extracted from the concrete for reuse.
Soft plastics in precast concrete
An early adopter of Polyrok, SVC is fully supportive of its uptake within the manufacturing and construction industries. To incorporate Polyrok into its own manufacturing processes, SVC has invested in operational upgrades and internal product trials to ensure successful integration. The company is now deploying Polyrok on a regular basis, while also reducing its consumption of stone aggregates.
Hundreds of concrete products across SVC’s broad range of Civil product solutions now contain a percentage of recycled soft plastics. These products are distributed across Victoria for use in council works, major projects and infrastructure programs, allowing these projects to achieve sustainability targets through material procurement.
Based on SVC’s current consumption of Polyrok, the numbers are impressive. Allowing a conservative estimate of 1.5 tonnes of Polyrok used per week at SVC, this translates to 72 tonnes of Polyrok per year, or a diversion of 18 million pieces of soft plastic away from landfill.
