The sand equivalent test is one of the most widely used quality-control checks in road
construction and aggregate production. It indicates the relative proportion of undesirable fine dust and
clay-like material in fine aggregate and granular soils. This guide explains what the test measures, the
apparatus required, the step-by-step procedure to ASTM D2419 and AASHTO T176,
how to calculate the result, and typical acceptance criteria.
What the Sand Equivalent Test Measures
Excess clay and fine dust coating aggregate particles weakens the bond between bitumen or cement and the
aggregate, reducing the durability of asphalt and concrete. The sand equivalent (SE) value expresses the
ratio of the sand reading to the clay reading as a percentage — a higher value means cleaner aggregate.
Apparatus Required
- Graduated transparent acrylic cylinder with rubber stopper
- Irrigator tube, weighted foot assembly and siphon assembly
- Measuring tin (85 ± 5 ml) and stock calcium chloride working solution
- Mechanical shaker for repeatable, operator-independent agitation
NL Scientific supplies the complete Sand Equivalent Test Apparatus
and the motorised aggregate & rock testing range,
built to ASTM and AASHTO requirements with ISO/IEC 17025 accredited calibration.
Test Procedure (ASTM D2419)
- Prepare the fine aggregate sample passing the 4.75 mm sieve.
- Siphon working solution into the cylinder to the 100 mm mark.
- Pour the sample into the cylinder and allow it to soak for 10 minutes.
- Agitate using a mechanical shaker for the specified time and stroke for repeatable results.
- Irrigate with the tube to flush fines upward and fill to the 380 mm mark.
- Allow 20 minutes of undisturbed sedimentation.
- Record the clay reading at the top of the suspension, then lower the weighted foot and record the sand reading.
Calculation
The sand equivalent is calculated as:
SE (%) = (Sand reading ÷ Clay reading) × 100
Always round up to the next whole percent and report the average of two tests.
Typical Acceptance Criteria
Specifications vary by authority and application, but a minimum sand equivalent of 45–50% is commonly
required for asphalt and base course aggregates, with higher thresholds for premium surface courses. Refer
to your project specification or local road authority standard for the exact limit.
Frequently Asked Questions
What is the difference between ASTM D2419 and AASHTO T176?
Both describe the sand equivalent test; the procedures are technically aligned, with minor differences in
sample preparation and reporting. NL Scientific equipment complies with both.
Why use a mechanical shaker instead of manual shaking?
A mechanical shaker delivers a consistent stroke and count, removing operator variability and producing
repeatable, defensible results.
Need the right equipment for your laboratory?
Contact NL Scientific for a quotation — Asia’s leading
manufacturer of civil engineering and material testing equipment, shipping worldwide.