Foamed bitumen stabilisation proves successful alternative on WA project

WA Stabilising discusses a recently completed major project for Main Roads WA in the Wheatbelt region and how foam bitumen stabilisation was used.WA Stabilising discusses a recently completed major project for Main Roads WA in the Wheatbelt region and how foam bitumen stabilisation was used.

With more than 2.5 million square kilometres of land in Western Australia, the ability to move quickly and respond to jobs is vital.

According to the Royal Automobile Club of WA, Western Australia is home to 20 per cent of the roads in Australia. To make sure all these roads remain in the good condition, maintenance is important, and the businesses maintaining the roads need to be able to react quickly to stay ahead.

WA Stabilising and its sister company WA Profiling, both part of the Global Civil and Mining Group, do so with well-trained staff and by prioritising mobility.

Daniel Bayne, Operations Manager at WA Stabilising, says that the companies have the largest fleet of Wirtgen profilers and stabilisers in WA, which helps them get their gear out across the state.

“Our ability to react quickly to a changing situation, mobilise additional resources, and change them if needed helps to keep the job on program,” Mr. Bayne says.

“We handle all our plant movements internally and we’ve got a large fleet of trucks, floats and ancillary gear. We don’t need to rely on transport heavy haulage divisions – we can handle that all ourselves.

“We’ve had work going on in the Pilbara, the Wheatbelt, Perth Metro, the Goldfields and also down south. With such a large fleet and being able to mobilise quite quickly, we can have gear spread from the northern end of WA right down to the south.”

Mr. Bayne says that WA Stabilising cross trains its workers in using both the profilers and stabilisers, which as milling machines are similar in how they operate.

“Several of the profiling team are also skilled in stabilising and vice-versa. It gives us cross utilisation which means we can set a profiler up and get a stabilising worker to handle it. That ability to adapt and change quite quickly means we’re not thrown off by changing conditions,” he says.

This agility is what helped the business complete a recent roadwork project in WA’s Wheatbelt region.

The project was originally awarded to WA Stabilising in November 2017 for a pavement repair contract. At tender, the project required 40,000 square metres of foam bitumen stabilisation and 120,000 square metres of full pavement rehabilitation.

“The project was spread out across various sites in the Wheatbelt network. If you were to drive from all the sites, there’d be over 1000 kilometres to drive through the whole area. It was a big area to move through, just like WA,” he says.

Mr. Bayne says a two-kilometre stretch of a section of road in the project was failing badly. The original scope of work was a 250-millimetre box out of the basecourse which would be disposed of, then stabilisation of the sub base, and a refill with new base course material.

The problem was identified as workers began to use the profiling machine to do box out work. Mr. Bayne says they hit rock in the basecourse and some of the lower layers, which meant they wouldn’t be able to stabilise the subbase layer.

“We were quick to get a phone call out to the client, Main Roads WA, to discuss alternative options. We performed some test holes to figure out what the extent of the rock was. What we found was sand in some areas, heavy clay in others and good subbase materials scattered throughout,” he says.

“To get that range of materials is well out of the norm. To handle these issues, we had some various changes in scope. It needed a heavier lime stabilisation, additional box out, overlay and foam bitumen, all of which provided for a sound pavement.”

Mr. Bayne says for one of the main intersections off of the Great Eastern Highway, on the Northam-Toodyay road, where a lot of the grain and heavy loads travel, the client decided to use foam bitumen stabilisation across the whole intersection.

Mr. Bayne says foam bitumen stabilisation is quick to put down and get finished, giving good strength gains and flexibility

With the project in full swing, there was a significant amount of heavy traffic on the roads, which included grain trucks and WA Stabilising’s own heavy vehicles. Mr. Bayne says traffic control was employed to handle this, which depended on good communication and careful planning.

Even with the unexpected hurdles that arose from the inconsistent ground conditions, WA Stabilising was still able to complete the project on time. Mr. Bayne says this is because WA Stabilising has a combination of experienced staff and advanced equipment which allowed for the team to adapt to the client’s changing design requirements. “Collaborating with Main Roads to get it resolved fast helped make the operation run smoothly. Their input and assistance helped us to find a solution as soon as possible.”

WA Stabilising was able to assist in the goals of Main Roads WA to provide world class outcomes for residents through, safe, reliable and sustainable roads to improve the mobility of people and freight.


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