Misclassifying a glacial till as a well-graded sand because someone skipped the hydrometer test is a classic mistake on Brantford construction sites. The difference between a silt and a clay fraction dictates everything from frost susceptibility to compaction behavior, and without the full curve from coarse gravel down to colloidal clay, you are essentially designing blind. Our laboratory generates complete particle size distributions using both mechanical sieving and hydrometer sedimentation, aligned with ASTM D422 and D6913 protocols. For projects near the Grand River where fluvial deposits alternate between gravel lenses and soft silts, we often couple the grain size analysis with an Atterberg limits evaluation to confirm plasticity characteristics that the gradation curve alone cannot reveal. The result is a defensible USCS classification that holds up under third-party review and eliminates costly rework from unexpected fill behavior.
A gradation curve without the hydrometer tail is just half the story—especially in Brantford tills where the silt-clay fraction controls frost behavior.
Methodology and scope
Local considerations
Brantford's industrial expansion along the Grand River corridor throughout the 20th century left a legacy of heterogeneous fill zones—old mill foundations, buried rail spurs, and undocumented backfill—that now underlie redevelopment parcels in the downtown core and Eagle Place. Encountering a pocket of poorly graded sand with zero fines beneath a proposed footing, directly adjacent to a silt-rich matrix, creates differential settlement conditions that standard bearing capacity checks can miss. Grain size analysis becomes the forensic tool that identifies these transitions before concrete is placed. Without hydrometer data, a contractor risks misidentifying a frost-susceptible silt as a non-frost-susceptible fine sand, leading to subgrade heave that manifests in the first spring thaw. The cost of a laboratory particle size distribution is negligible compared to ripping out heaved pavement or underpinning a settled foundation on the north side of town where the water table sits within two metres of grade.
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 (USCS), MTO OPSS 1010: Material Specification for Aggregates – Base, Subbase, Select Subgrade, and Backfill Material
Associated technical services
Combined Sieve and Hydrometer
The complete package for Brantford glacial tills and alluvial soils. Dry sieving from 75 mm down to the No. 200 sieve, followed by hydrometer sedimentation on the minus-200 fraction. Delivers the continuous curve that geotechnical reports require for foundation design and subgrade classification.
Wash Sieve Analysis
Targeted analysis for granular materials where the fines content is the primary concern. We wash the sample over the No. 200 sieve, oven-dry both retained and passing fractions, and report the precise percentage of silt and clay. Ideal for OPSS 1010 aggregate compliance testing in Brantford road construction projects.
Rapid Hydrometer Screening
When drill logs show a borderline silt-clay transition, we run an expedited hydrometer analysis on the minus-75 μm fraction to confirm the USCS classification without the full coarse sieve suite. Useful for trench backfill verification and utility bedding assessments where clay content limits apply.
Typical parameters
Frequently asked questions
What does a combined sieve and hydrometer test cost for a Brantford project?
A complete combined analysis—mechanical sieving plus hydrometer sedimentation on the fines fraction—typically ranges from CA$140 to CA$270 per sample, depending on the gradation complexity and whether wash sieving is required for materials with high silt content. Turnaround is generally three to five business days from sample receipt.
Why is the hydrometer portion necessary for Brantford glacial till?
Port Stanley Till commonly exhibits 30 to 50 percent passing the No. 200 sieve, meaning nearly half the soil mass consists of silt and clay-sized particles. Without hydrometer sedimentation, you cannot quantify the silt-clay ratio, which directly governs permeability, frost susceptibility per MTO OPSS 1010, and the final USCS classification. Sieve-only analysis on these materials produces an incomplete and potentially misleading gradation curve.
How are the results reported and can you classify the soil?
Each report includes a semi-logarithmic gradation plot with D-values (D10, D30, D50, D60, D90), coefficients of uniformity and curvature, a tabulated data set showing percent passing by sieve size, and the USCS classification per ASTM D2487. We also note whether the material is frost-susceptible under Ontario standards, which is critical for Brantford subgrade design given local frost penetration depths around 1.2 metres.