Innovation

Our Waikato teams are making significant progress in road maintenance by successfully trialling heavily stabilised pavement at six high-risk sites across the East Waikato state highway network. This initiative is part of the 2024/25 annual rehabilitation programme for the East Waikato Network Outcomes Contract, involving a strong collaborative approach between NZ Transport Agency Waka Kotahi, Beca and Higgins to deliver value for money design and construction outcome.

By incorporating a higher density of cement and lime into the pavement, the road becomes more 'concrete-like,' enhancing its durability, resistance to moisture infiltration in varying climates, and increasing its load-bearing capacity. This in-situ process not only brings cost savings by avoiding the need to replace the entire basecourse but also extends the overall lifespan of the pavements.

Ryan Dalton, Senior Project Manager, says, “This is an exciting development, exploring more effective and cost-saving treatment options. We are eager to see the benefits throughout the East Waikato state highway network.”

Our Specialised Engineering team is achieving remarkable results in bitumen sprayer technology.

An innovative recent sprayer build for parent company Higgins has produced significant improvements in usability, functionality and efficiency.

The sprayer is designed to allow for automated bar movements for lap joints, road edges, and kerb and channel. Along with surface texture scanning for automated variable application rates, it also features fully autonomous self-driving and spraying.

Greg Dobson, Specialised Engineering Services Manager, and Travis Etheridge, Specialised Engineering Services Design and Technical Engineer, highlight the build as a major leap forward in sprayer technology. “We have been targeting significant maintenance cost reductions, enhanced automation, and precise control of spray bar positions and nozzles, leading to higher accuracy, repeatability, and reduced surfacing defects. With this in mind, we’ve created something exceptional.”

By collaborating with current and former operators, the team incorporated valuable feedback to develop enhancements. These include the ability to control individual nozzles or spray bars as a group, allowing operators to spray complex shapes and back-to-back patches of varying sizes in single passes. This efficiency reduces the number of spray passes, chip truck passes, and lane closures, ultimately lowering the cost of chip sealing patches and seal repairs.

“We aimed to make the operation of a telescopic sprayer simple and intuitive while enabling complex tasks – and we’ve succeeded.”

Higgins is exploring the wider use of biogenic (plant-based) bitumen for building asphalt and chip seal pavements.

Adding plant-based biogenic components to binders used in bitumen can help decarbonize road construction by capturing an increasing amount of carbon in road surfaces or other asphalt-based products as they are recycled and reused over time.

Higgins is hopeful of a successful development in this area, which will extend our contribution towards the Fletcher Construction roadmap for a 30% reduction in carbon emissions and a sustainable future "for generations to come".

We used a remote control roller in our work to repair one of the major slips in Coromandel (McBeth-Opoutere). We built a retaining wall to support the road above, backfilled it, and the roller has just finished levelling.

The remote control roller was used in areas where we need to flatten ground near any steep drop-offs. This means if something did go wrong and the roller tipped off the edge, none of our people would be hurt in the process.