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Grain Size Analysis (Sieve + Hydrometer) in Burlington

Geotechnical engineering with regional judgment.

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Burlington sits on the boundary of the Niagara Escarpment with overburden that shifts from silty clay till to sandy outwash in less than a hundred meters. That variability shows up in every grading plan we review. In our experience, contractors who skip a full grain size analysis on fill material end up with compaction problems that surface months later. The combined sieve and hydrometer method gives the complete curve—from gravel down to clay fraction—needed for USCS classification and for predicting how the material will behave under load. Whether the sample comes from a cut on Brant Street or a borehole near the lake, we run the hydrometer test alongside the sieve stack because Halton Till rarely tells the whole story with sieves alone.

A hydrometer curve is the only way to catch a gap-graded till that looks uniform in a sieve stack but will consolidate unevenly under load.

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Methodology and scope

The silt content in Burlington glaciolacustrine deposits is what catches engineers off guard. A sample might look like clean sand in the field but 15% passing the #200 sieve changes the frost susceptibility completely—something the frost-heave evaluation clarifies when paired with Atterberg limits. Our procedure follows ASTM D6913 for the sieve portion and ASTM D7928 for the hydrometer sedimentation phase. That means washing the fines through a 75 µm sieve, oven-drying the coarse fraction, and running a deflocculated suspension in a temperature-controlled cylinder. Readings at 2, 5, 15, 30, 60, 250, and 1440 minutes build the fine-particle distribution curve. The lab maintains the dispersant concentration and water bath at 20°C ± 0.5—small deviations shift the Stokes' Law calculation enough to misclassify a silty clay as a clayey silt.
Grain Size Analysis (Sieve + Hydrometer) in Burlington
Technical reference — Burlington

Local considerations

A lab that runs only dry sieving on Burlington samples is going to miss the silt lens that turns a Class B backfill into a settlement problem. We see it in older subdivisions near the escarpment where imported fill was placed without hydrometer verification—differential movement appears within two freeze-thaw cycles. The risk is not just classification error. Silt-rich soils with a flat hydrometer curve between 0.02 and 0.002 mm are borderline frost-susceptible under Ontario Provincial Standard OPSS 1010. Calling that material clean sand because the coarse fraction dominates is a misread that costs money in subgrade replacement. We cross-check every hydrometer result with a plasticity index when the clay fraction exceeds 5% because the interaction between gradation and mineralogy dictates the real drainage and strength behavior.

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Explanatory video

Applicable standards

ASTM D6913-04 (2017) Standard Test Methods for Particle-Size Distribution of Soils Using Sieve Analysis, ASTM D7928-21 Standard Test Method for Particle-Size Distribution of Fine-Grained Soils Using the Sedimentation (Hydrometer) Analysis, ASTM D2487-17 Standard Practice for Classification of Soils for Engineering Purposes (Unified Soil Classification System), OPSS 1010 Material Specification for Aggregates – Base, Subbase, Select Subgrade, and Backfill Material

Technical parameters

ParameterTypical value
Sieve range75 mm (3 in) down to 75 µm (No. 200)
Hydrometer methodASTM D7928, 152H hydrometer, sodium hexametaphosphate dispersant
Sample mass (coarse fraction)500 g to 20 kg depending on nominal max size
Fines suspension preparationMechanical stirrer, 16-hour soaking period
Temperature correctionWater bath at 20°C ± 0.5, meniscus correction applied per reading
Classification outputUSCS per ASTM D2487, AASHTO M 145
Typical report turnaround3–5 business days, 48-hour rush available for Burlington projects

Frequently asked questions

What does a combined sieve and hydrometer grain size analysis cost in Burlington?

For a standard combined analysis—sieve stack through No. 200 plus full hydrometer sedimentation—the typical price in Burlington ranges from CA$140 to CA$270 per sample, depending on whether the sample needs pretreatment for organics or carbonates. Rush turnaround adds a small surcharge. We recommend budgeting toward the higher end for glaciolacustrine soils where organic content is expected.

How long does the hydrometer portion take?

The sedimentation phase runs a minimum of 24 hours because the final readings at 1440 minutes are what define the 0.001 mm fraction. Sample preparation—soaking in dispersant, mechanical mixing, and temperature equilibration—adds another working day. A complete combined curve from sample receipt to signed report is normally three to five business days.

Do I need the hydrometer if my material looks like clean sand?

In Burlington, yes. The Halton Till and glaciolacustrine deposits across the city frequently contain silt seams and clay laminae that are invisible in a hand sample. If the washed #200 fraction exceeds 5%, the hydrometer curve is the only way to correctly assign a USCS group symbol and assess frost susceptibility under OPSS 1010.

What sample size do you need for a full grain size analysis?

For a combined sieve and hydrometer test, we ask for at least 500 grams of material passing the #10 sieve plus a representative bulk sample of about 2–5 kg for the coarse fraction. If gravel particles larger than 19 mm are present, we need enough total mass to run the full coarse sieve stack per ASTM D6913. Our Burlington clients typically deliver samples in sealed plastic bags or five-gallon pails, and we can arrange pickup on jobsites between Aldershot and the QEW corridor.

Location and service area

We serve projects across Burlington and its metropolitan area. More info.

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