The ALF: 40th Anniversary Part 2

This year marks ALF's 40th anniversary. Our Accelerated Loading Facility has shaped engineering, academia, and Australian pavement standards since 1984. We're celebrating with a three-part series exploring ALF's journey and its impact on the transport sector over four decades.

Part 2: The Golden Years; 1990-2000

In the 1990s, the ALF truly hit its stride, ushering in what many who worked with the machine fondly remember as its 'Golden Years'. This decade saw ALF's influence expand far beyond its origins, becoming an indispensable tool in shaping Australia's road infrastructure. During this period, ALF wasn't just testing pavements – it was transforming how we approached road design and construction across the nation.

The ALF continued to provide infrastructure and cost-effective benefits for Australian federal and state transport authorities through numerous pavement trials conducted in several states. Each project it tackled added to a growing body of knowledge that would shape road engineering for years to come. Its work during this decade led to insights into pavement behaviour, influencing everything from material selection to construction techniques.

Pavement Heating System

As ARRB was transitioning through a process of privatisation, the ALF was widely regarded as support for research involving accelerated pavement testing was increasing. A slew of projects was conducted during this decade including:

• Fatigue performance of asphalt
• Geotextile reinforced seals
• Fine grained marginal materials
• Bitumen and bitumen/cement-stabilised crushed rock
• Crushed rock axle-load equivalency
• Crushed rock moisture/compaction
• Lateritic gravel pavements
• Rut-resistant properties of asphalt mixes
• Deep lift in situ recycling
• Stabilised fly ash pavements
• In situ stabilisation of marginal sandstone with slag/lime and bitumen/cement
• Granite sett pavements
• Design characterisation of rigid pavements
• Performance of maintenance treatments

In 1990, the ALF was commissioned to conduct a year full of field trials in Mulgrave focused on cement-treated crushed rock (CTCR). This was the first trial using the ALF to include extensive laboratory characterisation as part of the project. The completed testing resulted in a revision of the design guides leading to cost savings through a reduction in pavement thickness.

Although most of the early 90’s trials were focused on heavily trafficked applications, the ALF also improved pavements in lightly trafficked roads. In 1991 the ALF travelled to Brewarrina in NSW to examine the structural performance of an expansive clay pavement with a geotextile reinforced seal wearing surface. The insights from these trials proved incredibly valuable for low traffic rural roads in which road user cost savings didn’t justify sealing but the provision of all-weather access was seen as a community service obligation. The benefits came in the form of road construction cost savings as the geotextile seasl road cost $60k per kilometer less than the most probable all-weather road alternative.

ALF at Pacific Power

In the mid 1990’s, the ALF conducted several trials in Beerburrum, which stand as a testament to ALF’s impact on road construction practices. These trails were a turning point in our understanding of bitumen stabilised crushed rock and crushed rock moisture & compaction, asphalt rut resistance, and lateritic gravel bases and subbases. A part of these trails was an Australian Asphalt Pavement Association (AAPA) funded R&D program to test methods for the stiffness and creep properties of asphalt which required the development of a pavement heating system to keep a high and uniform temperature.

It’s important to note that many members of industry sponsored trials during this decade including: RTA NSW, Queensland Department of Main Roads, VicRoads, Transport SA, Commonwealth Department of Transport and Regional Services, Brewarrina Shire Council, US Army Corps of Engineers, AAPA, Shell Co of Australia, Mobil, BP, Pacific Power, Sydney Opera House Trust, and many more.

As ALF's reputation grew, its influence began to extend far beyond the confines of research circles. These trials, along with numerous others across the country, solidified ALF's status as a pivotal tool in road engineering. As word spread of this unique machine and its potential to improve local roads, ALF developed a larger public profile. One of ALF’s project leaders at the time, David Fossy remarks, “Back when we were testing roads on location throughout Australia ALF had a larger public presence. We would get local newspaper articles which showed that somebody was doing something about the roads...Pre 2000's, ALF was really the only high public profile piece of equipment that the public would see.”

ALF at Brewarrina

Eventually, at the end of the decade funding was dramatically reducing as federal support eventually dropped to zero. ALF was mainly testing granite sett pavements for the Sydney Opera House Trust to make sure of their ability to withstand the increased movements during the upcoming 2000 Sydney Olympic Games. Using the ALF for project level issues plummeted, but interest in research to address network-level issues was increasing. The Alf was about to evolve as an infrastructure research tool as it entered the modern era.

The ALF's Legacy

The ALF’s continued field testing in its golden years, and the continued exploration of pavement innovation, design, and cost-savings ultimately solidified Australia as an international leader in pavement research. ALF's legacy is written in the roads that now last longer, perform better, and cost less.

Part three of this three-part series will be released in December.

Acknowledgement and thanks to Kieran Sharp, Ray Brindle, Max Lay, John Metcalf, Ian Johnston, and Dave Jones, who wrote ARRB: The First Fifty Years (book), from which this series has referenced.

Sharp, K & Lay, M 2011, ARRB: the first fifty years, ARRB Group, Vermont South, Vic.