Bunbury sits on the Swan Coastal Plain, where sandy soils and a shallow water table (often 2–4 m deep) dominate. For existing pavement evaluation in Bunbury, these conditions demand careful assessment: high permeability can accelerate subgrade moisture changes, while fine sands may lose bearing when saturated. We combine falling weight deflectometer testing with in-situ CBR checks to map remaining structural life. Before recommending a rehabilitation strategy, we often cross-reference results with a drenaje vial study to rule out water damage and a subrasante vial analysis to confirm support layers meet AS 1726 requirements.
Bunbury’s sandy subgrade and shallow water table can cut pavement life by half if drainage and layer stiffness are not verified through field testing.
Methodology and scope
- FWD testing at 20 m intervals to produce deflection profiles
- Core recovery for thickness and mix design checks
- Dynamic cone penetrometer in unbound layers for stiffness profiling
Local considerations
With a population exceeding 75,000 and a port handling over 14 million tonnes of cargo annually, Bunbury’s pavements endure heavy loads daily. Heavy haulage routes to the port and industrial zones are particularly stressed. Without a proper existing pavement evaluation, hidden debonding or base course pumping can trigger premature failure, leading to costly emergency repairs. We assess fatigue cracking potential using the Shell method and check for moisture damage through field permeability tests. Identifying these risks before overlay or reconstruction saves both time and money.
Applicable standards
Austroads Guide to Pavement Technology Part 5: Structural, AS 1726 – Geotechnical Site Investigations, AS 4678 – Earth Retaining Structures, Main Roads Western Australia Supplement to Austroads
Associated technical services
FWD and Deflection Analysis
Full Falling Weight Deflectometer survey with back-calculation of layer moduli, residual life estimation, and overlay design recommendations.
Pavement Coring and Sampling
Recovery of 100 mm cores for thickness, density, and mix design verification, plus DCP profiling for unbound layers.
Typical parameters
Frequently asked questions
What is the cost range for an existing pavement evaluation in Bunbury?
For a standard road or car park project, the evaluation typically ranges between AU$2,030 and AU$6,340. The final figure depends on the number of test points, core samples, and whether FWD or DCP is the primary method.
How long does a pavement evaluation take on site?
A typical 500 m section with FWD at 20 m spacing and 5 core locations takes one day on site. Reporting and analysis add another 3–5 business days depending on data volume and back-calibration complexity.
Can you evaluate a pavement that has already been overlaid?
Yes. We adjust our testing plan to account for multiple layers. FWD deflection basins combined with core records allow us to back-calculate moduli of both the original and overlay layers, identifying which layer is actually failing.
Do you need traffic management for FWD testing?
Yes, FWD is a stationary test requiring lane closure. We coordinate with your traffic management provider or can recommend one. Testing is usually completed in half-day windows to minimise disruption.