The Koo Wee Rup Swamp in south-eastern Victoria once extended over approximately 40,000 hectares.
Near the end of the 1800s, the swamp was drained and opened up to agricultural opportunities. This paved the way for settlements and towns to grow and flourish.
These days the once-expansive swampland is now home to communities, townships and a large number of Victorians. Some pockets in the area still bear the same traits as a swamp, making it tricky to undertake any kind of construction work without issue. Chris Elenius knows this problem all too well.
“Down in Tynong, its basically a swamp and the water table is only a metre below the surface at best,” he says. “And what we had to achieve was to basically bridge that.”
In January this year, Mr. Elenius, Manager at Stabilime Distributors, headed up the project to construct the new Pakenham Racecourse at Tynong, located on Nar Nar Goon in the Koo Wee Rup Swamp.
The Pakenham Racing Club, in conjunction with Racing Victoria Limited, contracted Stabilime to build the new synthetic track inside the course proper at the proposed site.
One of the main issues Mr. Elenius and his team identified prior to construction was the terrain they needed to build upon. The synthetic track also had to be built for year-round operation. “We had to build a pavement that was robust enough to withstand the hooves of horses and maintenance vehicles,” he adds. “There was a very fine line.”
Construction of the synthetic track itself required more than 38,000 square metres of lime stabilisation and 38,000 square metres of cement stabilisation, including a couple of isolated ground water springs, which required separate stabilisation solutions.
Not only was the level of the water table a major obstacle for Mr. Elenius and his team, but they also had to complete construction in just one week. An unforgiving weather forecast gave Mr. Elenius and his crew a seven-day gap between downpours to undertake the task. “The longer we left it the more issues we had,” he says. “We took the plunge and thought: ‘Let’s get into it’”.
The work had to have as little impact as possible on the day-to-day activities at the partially-built track, particularly as training was taking place during construction. “We weren’t allowed to start before 7.30am, and that’s also part of the quick turnaround – to try and not disrupt the goings on around the place,” he says.
Official construction began on 29 January with the first round lime stabilisation. The subgrade material was treated with three per cent lime and the lime treatment of the material was used to assist in drying the existing base prior to cementing. Mr. Elenius explains that to successfully waterproof the subgrade, particularly with such a high water table, they had to carefully monitor the amount of moisture going into the ground during the stabilisation without oversaturating it. “That was quite a big challenge,” he adds.
Using a Wirtgen 2400 stabilising machine, the first crew managed to complete nearly 10,000 square metres of lime stabilisation. The next day a second crew came in and undertook the cement stabilisation on the lime-stabilised areas, running concurrently with the first crew.
The base material was treated with three per cent cement. This treatment provided a bound layer that gave additional strength and was designed to mitigate material migration from the base into the drainage layer.
The site had areas prone to water ingress from localised ground water springs, which required nearly 750 square metres of double-lift work to provide greater bearing capacity.
“We ended up doing 76,666 square metres of stabilisation – that’s a huge effort in a week,” says Mr. Elenius. The Pakenham Racecourse at Tynong is now fully operational. Not only are the clients, the horse trainers and the jockeys impressed with the outcome of the project, but so is the Australian stabilisation industry.
Stabilime was presented with the Innovation or Excellence in Sustainability award at the 2015 AustStab Awards of Excellence in July for its work on the Pakenham Racecourse synthetic track project.
Mr. Elenius says it was a great honour to be recognised at the awards, particularly as it was quite a unique project. “We have done some work on racecourses before. There was one in Adelaide and we do some maintenance work at Flemington, Caulfield and Werribee, but not to this extent – this was a full-on stabilisation job.”
The success of the project comes down to the innovation employed by Stabilime as well as the attitude towards the task at hand. When asked what his thoughts were prior to tackling the daunting task of stabilising nearly 77,000 square metres of area in just seven days, Mr. Elenius says he and his team weren’t apprehensive at all. “We always go in with a positive attitude – we pride ourselves on being the answer to people’s problems.”