Plastic on the Wimera

WORKING ON

THE WIMMERA

WHEN TASKED WITH RE-SEALING A SECTION OF THE WIMMERA HIGHWAY IN VICTORIA, RICH RIVER ASPHALT TEAMED UP WITH ROAD MAINTENANCE TO TRIAL ITS NEW BINDER, FEATURING RECYCLED PLASTIC AND RUBBER.

Rich River Asphalt is an asphalt manufacturer, supplier and contractor that services the Echuca and Moama area, on the border of Victoria and NSW.

In 2019, Rich River was faced with the task of spray sealing approximately 850 metres of the Wimmera Highway. The Department of Transport requirements for this section of the road was for a High Stress Seal (HSS) which uses a polymer.

In order to get good coverage of the existing modified binder and to prevent reflective cracking, a 14-milimetre HSS seal was applied on top of the existing 10-milimetre primer seal.

At the same time the team at Road Maintenance, an asphalt pavement crack seal and spray seal specialist, was developing a new HSS binder called B08, which includes 2.4 per cent waste plastic and 23 per cent recycled tyre rubber.

Road Maintenance has been using crumb rubber in its crack and spray seal binders for decades. However, as the industry has evolved to implement other recycled products, the company wanted to investigate what else was possible.

The B08 seal on the Wimmera Highway was the starting point for the

Road Maintenance surface texture results for the spray seal surface on the Wimmera Highway: B08 Surface Texture results

• The OWP results ranged from 2.2mm to 2.7mm. • The IWP results ranged from 2.2mm to 2.9mm. • The BWP results ranged from 2.7mm to 3.5mm. • The CL results ranged from 1.8mm to 2.0mm (Binder Overlap).

S35E Surface Texture results.

• The OWP results ranged from 2.8mm to 2.9mm. • The IWP results ranged from 2.7mm to 2.9mm. • The BWP results ranged from 3.5mm to 3.7mm. • The CL results ranged from 2.5mm to 2.7mm (Binder Overlap).

development of Road Maintenance’s B08 series called Maxi-Cycle, a polymer modified bitumen range using recycled crumb rubber and recycled plastics.

Max Fitzgerald, Road Maintenance Owner, says he has received a lot of interest in this recycled plastic and crumb rubber product and he is excited to be trialling it.

For the trial, Rich River Asphalt sprayed a commonly used binder on 450 lineal metres of the road and then Road Maintenance’s BO8 mix was sprayed to cover the remaining 400 metres.

Ray Lykles, Asphalt Manager at Rich River Asphalt, says the company decided to use B08 as a result of the push in industry to produce sustainable products that use recycled materials.

Incentives such as the Recycled First policy in Victoria, are clear indicators that contractors and government are working towards a circular economy.

“We haven’t heard of anyone with a binder that mixes recycled plastic and tyre rubber before, it has been used in some asphalt mixes but we haven’t seen it used for spray sealing, so we wanted to get involve d and trial the product,” Mr. Lykles says.

He says there was not much difference in the process to spray seal using the B08 binder, however it did become quite viscous on site.

The spray sealing works were based five hours away from where Road Maintenance homogenises the binder and it was temperature controlled on the way to site. The product was then loaded into trucks at 190 degrees Celsius at the depot and then further heating was required on arrival to bring the binder up to 200 degrees.

“There was a challenge to load the B08 material into the sprayer as it did become quite viscous, so the product was hard to

pump out of the tanker. But I know Road Maintenance is working to improve this aspect now,” Mr. Lykles says.

In order to reduce the viscosity of the binder for future use, Road Maintenance has been developing and improving the homogeneity and lowering the viscosity of the product.

The company has since created a B14 product with lower viscosity and a higher softening point.

Once the B08 product was sprayed across the surface of the Wimmera highway a pre-coated aggregate was spread immediately followed by two rollers; one multi-tyre roller and one a combination with a flat rubber vibrating drum and multi wheeled tyres.

Road Maintenance returned to the site seven weeks later to record a visual assessment and texture depths on 14 May 2020.

Depths were taken on the Outer Wheel Path (OWP), Between Wheel Path (BWP), Inner Wheel Path (IWP) and the Centre Line (CL).

When the B08 surface texture results were compared to the S35E results in the same paths, the B08 had smaller depths for all paths. (See the breakout box for each measurement)

Mr. Lykles says he expects the binder to perform well although it is early days.

“We don’t expect anything less in terms of performance than what a standard S45R binder would produce. But the B08 binder has plastic and rubber in it so it’s getting rid of a waste product to start,” he says.

The section of the Wimmera Highway with the completed B08 seal.

GRADES

Maxi-Cycle S06 Maxi-Cycle S08 Maxi-Cycle A28 Maxi-Cycle A30 Maxi-Cycle 2 CS Comparison to *(Table 5.1 AGPT/T190) S45R

APPLICATION

Spray Sealing Spray Sealing Asphalt Asphalt Crack Sealing

VISCOSITY (Spd31/Spd12) Austroads AGPT/ T190

2.0-2.5

2.5-3.0

3.0-3.5

3.5-3.8

4.0-6.5

4.5max

TORSIONAL RECOVERY

Austroads AGPT/T190

30-45

45-55

45-55

55-70

60-70

25-55%

SOFTENING POINT

Austroads AGPT/T190

62-80

70-90

70-90

82-105

95-100

55-65

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