On a recent industrial shed project near the Port of Bundaberg, the contractor assumed the sandy soil would drain perfectly and never settle. They were wrong. That kind of misjudgment happens when you skip a proper grain size analysis. We walked the site after the slab cracked and saw the problem immediately: a hidden layer of fine silty sand that behaved like clay when wet. That is exactly why we insist on running both sieve and hydrometer tests on every Bundaberg project. The hydrometer catches the particles that the sieve lets through, and together they give you the full gradation curve. Without that data, you are guessing how the soil will behave under load or when saturated. For deeper site understanding, we often pair this with an ensayo SPT to correlate gradation with penetration resistance.
A single missing silt fraction in the gradation curve can turn a free-draining fill into a water-retaining slab killer.
Methodology applied in Bundaberg
Working video
Typical technical challenges in Bundaberg
The most common mistake we see in Bundaberg is relying solely on the visual description of the soil. A builder looks at a sandy loam and calls it 'good draining sand', but the fines content is 18% and the hydrometer shows it is plastic. That soil will hold water, it will pump under traffic, and it will cause differential settlement under a slab. By the time the cracking appears, the foundation is already compromised. A proper grain size analysis with hydrometer extension catches that problem before the concrete truck arrives. It costs a fraction of what one slab repair costs, and it saves weeks of schedule delay.
This service complements our laboratory testing work for a complete project analysis.
Our services
We offer a complete suite of grain size analysis services tailored to Bundaberg conditions, from quick sieve-only checks to full hydrometer curves for fine-grained soils.
Sieve Analysis (Coarse Soils)
Dry sieving for gravels and sands down to 0.075 mm. Ideal for road base, fill materials, and aggregate acceptance at local Bundaberg quarries.
Sieve + Hydrometer (Fine Soils)
Full gradation curve including silt and clay fractions. Required for embankment design, pavement subgrades, and any site with suspected plastic fines.
Wet Sieving with Dispersion Check
For soils that tend to clump or contain clay lumps. We wash the sample through the sieves and run a hydrometer on the wash water to capture true fines content.
Frequently asked questions
Why do I need both sieve and hydrometer for Bundaberg soils?
Bundaberg soils often contain a significant silt fraction that passes the 0.075 mm sieve but behaves differently from sand. The hydrometer test resolves that fraction down to 0.001 mm, which is critical for assessing drainage, compaction behaviour, and frost susceptibility. Without it, you might underestimate the plasticity of the fines.
How much does a grain size analysis cost in Bundaberg?
A standard sieve-only test typically ranges between AU$160 and AU$240. If you need the full hydrometer curve, the cost goes up to AU$280–AU$330 due to the 24-hour sedimentation process. The exact price depends on sample quantity and whether dispersion pre-treatment is required.
What sample size do you need for the hydrometer test?
We require approximately 200 g of material passing the 2.36 mm sieve for the hydrometer test. For the combined sieve and hydrometer, we need about 2 kg of bulk sample to ensure the coarse fraction is representative. We can advise on sampling procedures for your specific Bundaberg site.
How long does the full test take from sample drop-off to report?
The sieve test alone takes 1–2 working days. The full sieve plus hydrometer takes 3–5 working days because the hydrometer requires readings at 1, 2, 4, 8, 24, and 48 hours. We can prioritize urgent projects if you need results faster for a Bundaberg construction schedule.