Opus Research - Paving the way for Wellington’s smart motorway

November 2016

Wellington's new smart motorway was completed using a novel long-life asphalt developed at Opus Research. Photo: Lindsay Keats, Opus Research.

Surfacing of Wellington’s new smart motorway was recently completed using a novel long-life asphalt developed at Opus Research in partnership with Fulton Hogan for the New Zealand Transport Agency. This is the first time the epoxy modified open-graded porous asphalt (OGPA) has been used in Wellington and will provide a quieter ride into and out of the city.

The development of the epoxy modified asphalt was driven by the user benefits it provides for the public and the cost savings resulting from the very long life expected. As well as being a low-noise asphalt, this type of surface allows free drainage of rainwater which will improve traffic safety through enhanced skid resistance and provide better visibility from reduced tyre spray. Conventional OGPA suffers from a short useful life. For road users, the long life expected from epoxy OGPA also means reduced delays, lower costs and fewer road works.

Before the application of the new surfacing the Transport Agency required extensive site investigations be undertaken to ensure that the underlying pavement was in good condition and suitable for this type of asphalt. Opus Research extracted cores of the old pavement and reviewed the quality of the existing materials in the laboratory as a specialist service for the Transport Agency.

During the two weeks of production and laying for the Wellington Motorway, Opus Research undertook quality control testing of the mix on behalf of Fulton Hogan and the Transport Agency.

The success of this type of asphalt depends on precise control of the manufacturing process. Because the material is expensive, maintaining good quality control is essential to ensure the value of the final product is preserved. A key factor is the amount of epoxy in the asphalt mix. To monitor the epoxy concentration Opus Research developed a new analysis method using an infrared spectroscopy technique. This innovative and rapid method allows the amount and relative proportions of the two epoxy components to be measured to within ± 1%.

Epoxy OGPA will be used in the next few months on the Cambridge section of the Waikato expressway and on the Western Corridor project (SH1 John’s Road upgrade) in Christchurch.

For more information please contact: Phil Herrington

For more information about research at Opus please see: http://www.opus.co.nz/services/research