Main Roads WA is exploring options for the use of C&D waste in roads, namely on the Kwinana Freeway.
RECYCLED ROADS
ON THE RISE
MAIN ROADS WESTERN AUSTRALIA IS INCREASING ITS USE AND IMPLEMENTATION OF RECYCLED CONSTRUCTION AND DEMOLITION WASTE IN ROAD CONSTRUCTION AND MAINTENANCE THROUGH A NEW PILOT PROJECT AND PRODUCT TESTING SCHEME.
W
ith a review of its waste strategy last year, the Western Australian Government has outlined some key targets in its draft Waste Strategy 2030 that aim to take the state’s waste management processes to the next level. One target included in the strategy is for construction and demolition (C&D) waste, the aim of which is to increase material recovery to 75 per cent by 2020. Main Roads Western Australia (MRWA) is already setting the benchmark for increasing the use of C&D waste in new and sustainable ways and taking up the challenge laid down in the strategy. For MRWA Principal Advisor Sustainability Louis Bettini, the hierarchy of sustainability known as “reduce, reuse, recycle” is an ethos that informs and helps guide the road authority’s decision-making processes. “The most effective way to increase sustainability is to reduce the amount of waste in the first place. Main Roads can contribute to this by ensuring it maximises the lifespan of its roads through good design and construction using durable materials, and encouraging the reuse of materials wherever possible,” Mr. Bettini explains. Much of the state’s road network is 40
ROADS FEBRUARY 2019
rehabilitated or strengthened with in-situ recycling processes to reuse the existing materials, rather than replace them, when they reach their end of life. Crushed recycled concrete (CRC) has been used on a number of MRWA projects in the past, which Mr. Bettini explains has performed well. “The material makes an excellent subbase under full depth asphalt pavements, providing a stiff underlying layer that will help extend the life of the pavement,” he says. The authority also uses plastics in asphalt and other bituminous products while encouraging suppliers to source recycled plastics where possible. “Different plastics have different effects on the bitumen and asphalt and must meet quality requirements to prevent detrimental impacts on service life,” Mr. Bettini adds. Late last year, the Department of Water and Environmental Regulation (DWER) approved the new Recycled Construction Products Program Specification, which has allowed the Main Roads department to include CRC as an approved sub-base for road projects. The move has set in motion a new pilot project that will see the recycled C&D waste product
rolled out on one of the state’s busiest road corridors – the Kwinana Freeway. In November last year, Western Australian Environment Minister Stephen Dawson and Transport Minister Rita Saffioti announced the Roads to Reuse (RtR) pilot. The RtR supports MRWA in using recycled C&D for road construction, namely through a pilot project set to take place on the Kwinana Freeway Northbound Widening Project. The project will see 25,000 tonnes of CRC used on the Kwinana Freeway works between Russell Road and the Roe Highway in early 2019. CRC will be used as road sub-base under full depth asphalt on the project. This will involve laying a 150-millimetre-thick layer of the product, which will form the stiff support layer under approximately 250 millimetres of asphalt. The material is a granular material mixture of fine-grained and coarse soils and crushed aggregate up to 20 millimetres in size, which will be placed by grader – like conventional quarry crushed rock-base material. Aside from the environmental benefits of using the CRC as a sub-base, Mr. Bettini says it includes positive engineering properties,
