The calibrated sand jar sits on the base plate while graded Ottawa sand flows steadily into the excavation. In Savannah, field density testing with the sand cone apparatus measures compaction layer by layer under the Georgia sun. Roadbeds along Abercorn Street, building pads near the marsh edge, and utility trenches in silt-rich ground all demand verification that goes beyond visual approval. ASTM D1556 governs the procedure from cone calibration to final density calculation, and the lab maintains ISO 17025 accreditation for each device deployed to the site. Savannah’s water table sits barely three feet down in many areas, and fill that looks solid after rolling can lose strength overnight if density falls short. The field team records wet density on site, then oven-dries samples at 110°C in the Savannah laboratory to determine moisture content and compute dry density against the Proctor maximum—a Proctor curve established for the specific borrow source used on the project.
A single failing density test on a utility trench backfill in Savannah can delay paving by a week while the contractor reworks the lift.
Method and coverage
Regional considerations
Savannah’s colonial grid, laid out by James Oglethorpe in 1733, placed the city on a forty-foot bluff above the Savannah River—but the expansion westward and southward since the 1950s has pushed development onto low-lying Quaternary terrace deposits and back-barrier marsh sediments. These soils compact well in the lab but behave differently under production rollers when humidity spikes or a summer thunderstorm saturates the fill before testing. Under-compacted structural fill beneath a slab-on-grade in these areas can settle differentially by two inches or more within the first four years, cracking partition walls and racking door frames. The sand cone test provides the direct density measurement that a proof roll cannot: it quantifies whether the contractor achieved the specified relative compaction—typically 95 percent of the modified Proctor maximum for building pads per IBC Section 1804, or 98 percent for pavement subgrade under GDOT specifications—before the next lift covers the evidence. For deep fill sections over compressible marsh clay, the field density data also feeds the settlement analysis that the slope stability evaluation requires when fill slopes exceed eight feet near property boundaries.
Process video
Standards that apply
ASTM D1556-15e1 Standard Test Method for Density and Unit Weight of Soil in Place by the Sand-Cone Method, ASTM D1557-12e1 Standard Test Methods for Laboratory Compaction Characteristics of Soil Using Modified Effort, IBC 2021 Section 1804 – Excavation, Grading, and Fill, GDOT Standard Specification Section 210 – Roadway Excavation and Embankment
Complementary services
Compaction Curve Development
Standard and modified Proctor tests—ASTM D698 and D1557—run on borrow samples before fill placement begins, establishing the target density and optimum moisture content that the sand cone field tests will reference throughout the job.
Routine Lift Verification
Scheduled sand cone testing at the frequency required by the project specifications, with results plotted on control charts showing percent compaction and moisture deviation per lift so the earthwork contractor can adjust roller passes or aeration in real time.
Forensic Density Investigation
Targeted sand cone tests on existing fill where settlement or pavement distress suggests under-compaction, coupled with laboratory re-evaluation of the reference Proctor to determine whether the original specification was achievable in the material placed.
Typical parameters
Q&A
How much does a sand cone field density test cost in Savannah?
Single sand cone field density tests in the Savannah area typically range between US$110 and US$150 per test when scheduled as part of a routine lift-verification program. The rate depends on the number of tests per mobilization, travel distance to the site, and whether the laboratory provides the Proctor reference curve or uses one supplied by the contractor.
How deep does the sand cone hole need to be?
ASTM D1556 requires the test hole depth to equal the compacted lift thickness. For a standard 8-inch loose lift that compacts to roughly 6 inches, the hole should be excavated approximately 6 inches deep. The ratio of hole diameter to maximum particle size must exceed 12:1, so material containing particles over 1.5 inches requires a larger-diameter test method.
Can the sand cone test be used when the soil is wet?
The sand cone method works on moist soil but not on saturated or free-draining material. If water seeps into the excavation during the test, the volume measurement becomes unreliable. In Savannah’s high-water-table zones, dewatering may be necessary before testing, or the contractor may shift to a nuclear density gauge or drive-cylinder method for saturated conditions.
How many sand cone tests are required per day on a typical Savannah earthwork job?
Frequency follows the project specification—commonly one test per 1,500 to 2,500 square feet per lift for structural fill, or one per 150 linear feet per lift for utility trench backfill. On a 10,000-square-foot building pad compacted in 6-inch lifts, expect roughly four to seven tests per lift, depending on uniformity of the material and the engineer’s observation of rolling patterns.