The difference between the clay-rich soils of South Austin near Onion Creek and the sandy loam of the Northwest Hills is dramatic. A fill placed in the volcanic ash-derived soils around Westlake demands a different approach than one atop the black clay of East Austin. That is why every compaction test we run in this city starts with a clear understanding of the local geology. We apply the sand cone method to measure in-place dry density and compare it against the maximum dry density from the Proctor test. This direct field density test provides the compaction ratio required by the project specifications. It is a simple, reliable check that has been used for decades. In Austin, where the Edwards Aquifer recharge zone adds regulatory layers, a documented density result is not optional. It is a requirement for any earthwork permit.
A documented field density test is your proof that the fill was compacted to the specified dry density in the Austin area.