Project summary

As part of the Great Western Highway upgrade through the Blue Mountains, specifically at Medlow Bath, Abergeldie Complex Infrastructure were engaged to deliver a new shared pathway over a retained embankment adjacent to the highway corridor, following the removal of the original path due to the highway widening works.

With limited corridor width available, the pathway design required extending partially over the capping beam to maximise usable path width. In addition to widening the path, Abergeldie also required the capping beam — which varied between 55 mm and 100 mm below the finished path level — to function as a linear drainage channel, capturing and dispersing surface water to reduce ponding and maintain slip resistance along the pathway.

By utilising StoneSet, a system typically specified as a full surface treatment, Abergeldie were able to achieve both outcomes within a single solution. StoneSet was installed over the capping beam to bridge the height variation between the beam and the adjacent pathway, creating a fully trafficable, slip-resistant surface that effectively widened the usable path. At the same time, StoneSet’s fully permeable structure allowed water to drain through the surface and into the capping beam channel below, helping to manage surface water and keep the pathway clear and safe.

Drainage Matrix

To accommodate the varying build-up depths along the capping beam, a Drainage Matrix layer was incorporated as part of the system build-up. Using Drainage Matrix bound with StoneSet’s non-UV resin variant allowed the depth to be efficiently built up where required, without the need to install StoneSet Premium (top layer) at an excessive depth of up to 86 mm, resulting in a significantly more cost-effective solution.

In addition to improving constructability and cost efficiency, the Drainage Matrix incorporates 10 mm aggregate, providing a higher void content than traditional surface layers. This increased void structure enhances permeability and lateral water movement, allowing water to efficiently travel along the capping beam beneath the permeable surface. This supported the project’s drainage strategy by reducing surface water retention while maintaining a stable, trafficable finish.

StoneSet Premium

The StoneSet Premium layer provides a hard-wearing, UV-stable surface suitable for all levels of pedestrian traffic, while maintaining high permeability to support effective surface water management.

To further enhance structural performance and ensure long-term durability, a fibreglass reinforcement mesh was installed between the Drainage Matrix and the StoneSet Premium layer. This additional reinforcement improves load distribution and crack resistance, contributing to a robust, stable surface capable of performing within a highly constrained highway environment.