Australia’s first Light Weight Deflectometer (LWD) standard released

Nov 9, 2020 | Uncategorized

We are very happy to let you know that Australia now has it’s own Light Weight Deflectometer (LWD) standard.

Test Method Q726B: Deflections – Portable Impulse Plate Load Test Device

Our Zorn LWDs are fully compliant with Q726B.

The standard has been developed by Department of Transport and Main Roads Queensland (DTMR) and is based on the ASTM E2835: Standard Test Method for Measuring Deflections using a Portable Impulse Plate Load Test Device.

The standard is one of the outcomes of the “Best practice in compaction quality assurance for pavement and subgrade materials – P60” National Asset Centre of Excellence (NACOE) project carried by Queensland Department of Transport and Main Roads (DTMR) and the Australian Road Research Board (ARRB). To find out more about this project, we have brought all the reports, presentations and webinars into one place.

Modulus is the most accurate and independent means for judging deformation (stiffness) and, thus, a materials level of compaction. Modern geotechnical and pavement designs are based on in-situ modulus values.

However, the traditional state of practice is to base the field-testing parameter selection on the result of a non-deformation parameter, such as DCP or CBR results from site investigation or density/moisture relationships in earthworks QA.

This means that there is currently a disconnect between design and construction control.

The Light Weight Deflectometer (LWD) addresses this gap and Queensland DTMR have recognised this.

By measuring the modulus value, the LWD provides the direct link between the design specification (design modulus value) and the actual site condition (in-situ modulus value).

The LWD enables one to:

(a) reliably provide a direct measure of the strength or insitu modulus value; and

(b) offers significant time savings in turnaround time of QA test results.

We believe this is major step forward in pavement construction and are privileged to have been playing our role in this transformation over the last 15 years taking deflection based testing from the early adopter phase to more main stream adoption in Australia, New Zealand and the Pacific Islands. 

We are very appreciative of all those who have encouraged us along the way including our fabulous clients. Thank you!

Insitutek imports, sells and services, unique geotech equipment that has proved of great benefit to those who use it. It has a particularly beneficial role to play for those compacting soil in infrastructure projects.

David Palmer

Earthmover and Civil Contractor

We purchased a PANDA 2 machine after using one from another laboratory. The information obtained has saved money on numerous jobs. It is reasonably priced and the after-market service has been great. Highly recommend using Insitutek.

Brett McDonald

Department of Transport and Main Roads, QLD

The Light Weight Deflectometer (LWD) was first used in 1998 by the Minnesota Department of Transportation (Mn/DOT) at the Minnesota Road Research Project. Starting in 2005 the LWD has been used by Mn/DOT as an acceptance tool for the compaction of roadbed and miscellaneous embankment and trench construction, culvert treatments and other tapered construction.

Minnesota Department of Transportation (Mn/DOT)

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