An On-Site Test Conducted to Determine the In Situ Density of the Soil

Sand Replacement Density (SRD) tests are used to evaluate the in situ density of natural or compacted soils. These tests are most commonly applied in highway or pavement design to estimate the relative density of base course or subgrade materials.

SRD tests are crucial for assessing soil compaction levels, ensuring proper foundation support, and contributing to the stability of infrastructure projects.

Conducted either at ground level or the prepared formation level, the SRD tests involve excavating a cylindrical flat-bottomed hole from the surface, approximately 200mm deep and 200mm in diameter.

The excavated material is preserved in a moisture-retaining container and weighed.

Sand with a known density is then poured into the hole using a calibrated cylinder.

By determining the weight of the sand required to fill the hole, the volume of the hole can be accurately calculated.

With the weight of the excavated soil known, as well as the volume from which it is excavated, the bulk density can be determined.

The excavated material is then dried out, which enables the calculation of the dry density, moisture content, and void ratio to a high level of accuracy.

This provides valuable data to assess soil properties for foundation design, compaction quality, and material suitability, which is essential for ensuring structural integrity.