We bring a full set of mechanical sieves and a hydrometer bath directly to your project site in Pasadena California. The equipment is calibrated and ready for both coarse and fine fractions. For soils with high fines content, the hydrometer phase captures particles down to 0.001 mm. This is essential before any cimentaciones sísmicas design, since the San Gabriel Valley alluvium can hide abrupt changes in gradation. Our team sets up the wash sieving station on location and runs the sedimentation test over 24 hours. The whole process follows ASTM D422 and D6913 strictly.
A poorly graded sandy soil in Pasadena can shift from non-plastic to highly plastic within one meter of depth.
Service characteristics in Pasadena California
Critical ground factors in Pasadena California
The Mediterranean climate of Pasadena California means dry summers and episodic winter storms. After heavy rain, the alluvial soils can become saturated, causing fine particles to migrate and clog the sieve mesh. If the sample is too wet, the hydrometer readings drift and the clay fraction is overestimated. We dry the material at 110°C before sieving and use a deflocculant for the hydrometer test. Another risk is misclassifying collapsible sands in the foothills — a common issue near the San Gabriel Mountains. Our lab protocols include a collapse potential check alongside the grain size curve.
Our services
We offer complementary services that build on the grain size data to give you a complete geotechnical picture.
Sieve Analysis (Coarse Fraction)
Mechanical sieving from 3 in. to No. 200. We determine the gradation curve for gravels and sands. This is the first step in classifying the soil according to ASTM D2487.
Hydrometer Analysis (Fine Fraction)
Sedimentation test for particles smaller than No. 200 sieve. We measure the percentage of silt and clay using a hydrometer and Stokes' law. Critical for evaluating plasticity and compressibility.
Combined Grain Size Report
We merge the sieve and hydrometer curves into a single continuous gradation. The report includes D10, D30, D60, uniformity coefficient (Cu), and coefficient of curvature (Cc). Ready for foundation or pavement design.
Common questions
What is the difference between sieve analysis and hydrometer analysis?
Sieve analysis separates particles larger than 0.075 mm (No. 200 sieve) by mechanical shaking. Hydrometer analysis measures particles smaller than 0.075 mm by sedimentation in water. Both are combined to obtain a complete gradation curve from gravel to clay.
How much sample is needed for grain size analysis in Pasadena California?
We typically require 500 grams for the sieve portion and 100 grams for the hydrometer test. For very coarse soils (gravels), we may need up to 2 kilograms. The sample should be representative of the soil layer being studied.
Which ASTM standards apply to grain size analysis in the US?
The primary standards are ASTM D422 (historical), ASTM D6913 for sieve analysis, and ASTM D7928 for hydrometer analysis. All are recognized by the IBC and ASCE 7 for foundation design in California.
How long does a complete grain size analysis take?
The sieve analysis takes about 2 hours. The hydrometer test requires 24 hours because of the multiple sedimentation readings (2, 5, 15, 30, 60, 250, and 1440 minutes). We usually deliver the full report within 3 business days.
What is the typical cost for grain size analysis in Pasadena California?
The price range for a combined sieve and hydrometer analysis is between US$90 and US$180 per sample. This includes the test, data processing, and a certified report. Volume discounts apply for large projects.
Coverage in Pasadena California
Process video
This service complements our laboratory testing work for a complete project analysis.