The acceptance of earthwork and unbound pavement construction in Australia currently relies on density testing and CBRs for Quality Assurance (QA). Though its National Asset Centre of Excellence (NACoE) research program, Queensland Main Roads has sponsored an ARRB research project to update test methods acceptable for use for QA of pavement and subgrade materials including Light Weight Deflectometer’s (LWD’s), PANDA Instrumented DCP, Clegg Hammer, DCP and Plate Load Testing (PLT). A state-of-the-industry study was completed by FSG Geotechnics & Foundations in 2017, and identified a number test methods that have the potential to:
(a) reliably provide a direct measure of the strength or insitu modulus value; and
(b) offer significant time savings in turnaround time of QA test results.
In 2018, field result trials were then used to bench mark various alternative equipment and compared with traditional density QA measurements to assess the reliability, benefits and limitations of these equipment.
Insitu Test have been collaborating with FSG / ARRB on this project with three devices we supply being utilised – the Zorn Light Weight Deflectometer (LWD), the Anix AX01 Instrumented Plate Load Test (PLT) and the PANDA Variable Energy Instrumented Dynamic Cone Penetrometer (DCP).
The report on findings is be expected to be available through the ARRB later in the year.
The Falling Weight Deflectometer (FWD) was not part of the evaluation as the research focused on general earthworks QA during construction. The FWD is useful to evaluate the structural condition of an existing pavement. The FWD is not considered portable (as compared to these devices) and is a different expense consideration for this application. However, for existing pavement evaluation over large lengths, the FWD would be the superior testing device.