In Rockhampton, we often see pavement failures caused by reactive clay subgrades that swell and shrink with seasonal moisture changes. Designing a flexible pavement here means more than just choosing an asphalt thickness; it requires a thorough understanding of the in-situ soil's bearing capacity, the expected traffic loads, and the local drainage patterns. Our team has assessed dozens of sites across the city, from the alluvial flats near the Fitzroy River to the more stable basalt-derived soils on the higher ground. For projects where the subgrade is particularly weak, we recommend a subrasante vial study to confirm the foundation layer's support before finalizing the pavement structure. This upfront work prevents costly repairs later.
A design CBR below 3 in Rockhampton's clay subgrades means we must either stabilize the soil or increase pavement thickness significantly.
Scope of work
Area-specific notes
The biggest risk we encounter in Rockhampton is ignoring the expansive clay behavior under the pavement. During a dry spell, the clay shrinks and cracks, then swells when the wet season arrives, causing differential heave that cracks the asphalt surface. Using a portable dynamic cone penetrometer on site, we measure the subgrade strength in real time across the pavement corridor. If we detect variability, we adjust the design to include a thicker granular layer or a geogrid reinforcement. This approach has saved several local road projects from premature failure.
Standards used
Austroads Guide to Pavement Technology Part 2 (AGPT02-17), AS 1289.6.1.1: Determination of the California Bearing Ratio, AS 1726:2017 Geotechnical Site Investigations
Linked services
Subgrade Investigation and CBR Testing
We conduct boreholes and test pits at proposed pavement alignments, extracting undisturbed samples for laboratory CBR and compaction tests. This gives us the design parameters specific to your Rockhampton site.
Pavement Structural Design and Cross-Sections
Using Austroads and local council guidelines, we produce detailed pavement cross-sections specifying asphalt, base, and subbase thicknesses, along with drainage recommendations for Rockhampton's rainfall patterns.
Construction Quality Control (CQC) Support
During placement, we perform field density tests with a nuclear gauge or sand cone, and verify compaction against the target values. Our team stays on site to ensure the pavement structure matches the design.
Typical parameters
FAQ
What is the typical cost for a flexible pavement design study in Rockhampton?
For a standard project in Rockhampton, the geotechnical investigation and pavement design report typically ranges between AU$2,640 and AU$8,390, depending on the number of boreholes, traffic loading, and site access complexity.
How deep do you need to drill for pavement design in Rockhampton?
For flexible pavement design, we drill to at least 1.5 m below the proposed formation level, or until we encounter competent material. In Rockhampton's clay profiles, this often means reaching 2–3 m to confirm the subgrade is uniform.
Do you account for the wet season when designing pavements in Rockhampton?
Yes. We always perform soaked CBR tests on samples compacted at optimum moisture content, because Rockhampton's summer rainfall can saturate the subgrade. Our designs include subsurface drainage layers to prevent water accumulation under the pavement.
Can you design a flexible pavement for a light industrial yard in Rockhampton?
Absolutely. For light industrial areas, we use a lower traffic loading but still account for occasional heavy vehicles. The design focuses on a durable asphalt surface over a well-compacted granular base, with attention to the local clay subgrade.