WSP team leader for testing services Zac Francis says taking core samples is a vital part of road engineering and construction. It helps ensure materials meet national standards and project specifications.
The new rig can collect samples from all road layers, including base course, sub-base, and asphalt. It can take samples using wet and dry coring methods and can accurately reach the right part of the road thanks to a side-shift drilling feature.
Core samples are taken back to the WSP laboratory and tested for strength, density, and air voids to check the road meets specifications and will perform as expected during its design life.
Zac says core sampling also provides a useful comparison between laboratory results and real-world performance.
“Materials produced and tested in the lab are assessed under ideal conditions, but on a construction site factors such as weather, equipment and workmanship can all affect the final result. By testing samples taken directly from the road, we can see if the required standards have been achieved in practice.”
WSP senior engineer for pavements and surfacing Alastair Pickard says the new rig is a significant health and safety improvement for operators, with remote controls, hydraulic leveling and safety guards.
The state-of-the-art rig will be used on major projects, state highways, and local roads for compliance and verification testing for clients that need core sampling and testing.
Roading specifications generally require a minimum of eight core samples to be taken from random locations for every 300 square metres of asphalt laid.
While coring leaves holes in the road surface, the new rig features built in equipment that allows them to be filled immediately using asphalt or concrete mixes.
Alastair says having modern, reliable equipment like this to safely and efficiently extract core samples is all about helping clients and their contractors prove build quality or catch issues early to minimise rework.
The new rig has already been used on projects in Hamilton and is expected to be deployed across much of the central North Island over the coming year.
