Optimising Concrete Highway Paving: An Australian Perspective

Wider Concrete Shoulders, Longitudinal Jointing Design, High Output Twin Shaft Mixing Plants, and the Journey Toward Full Width Concrete Paving

Abstract

A typical Australian Highway pavement is 10-10.5m wide, consisting of 2.5m nearside shoulder, 2x3.5m travel lanes and an offside shoulder of 0.5-1m. For many of these high speed - high volume - high heavy vehicle usage corridors, rigid pavements are the workhorse that provide durable, low maintenance, longer lasting roads. Current construction practices and Transport for New South Wales (TfNSW – the State Road Authority for New South Wales, Australia) Standard Drawings would see the paving of travel lanes and offside shoulder in first pass utilising multi-lane paver and tipper trucks. Following the first pass gaining strength, the shoulder would be paved with smaller paver and concrete delivered with tipper trucks or agitators. Proposals to construct the full width of pavement as a single pass have been raised by many over the years. Modern high output twin shaft mixing plants have been utilised in Australia since the turn of the century, making it possible to pave full width in single pass. With Australian Road Agencies seeking to improve road safety outcomes for all, there has been ongoing calls for increased nearside shoulders to ensure they can function as a breakdown lane, with shoulder widths as wide 4m. This would result in a cross section up to 12m. While this represents a huge improvement for road safety, it also raises the need to reconsider the case for full width concrete paving. Particularly when one considers potential benefits:

• Safety during paving operations
• Construction quality
• Potential paving program efficiencies, and
• Potential cost savings