If you follow baseball, you know that every team has a roster spot for a utility player. Trained to play several positions on a team, they are asked to fill in and put in a good shift whenever asked. When I was hired here at Howell in November 2025, after 20+ years at the Chester County Conservation District, I didn’t really know what my role would be. As it turns out, I was slotted into the Environmental Team and then pretty much asked to fill in wherever and whenever needed. So far, I’ve helped with infiltration testing, sewage facility planning, all phases of NPDES work, construction oversight, critical-stage inspections, and Quality Assurance and Quality Control (QAQC) reviews with the Engineering Team. I’ve also gone on a few ePhase site visits to see how that works.

My latest project was with the Geotech Team, performing compaction testing with a nuclear density gauge, and that’s what I will focus on here.

So, what is a nuclear density gauge?

A nuclear density gauge, or as it is commonly referred to, a nuke gauge, is a portable, non-destructive device used in construction to quickly measure the density of soil, asphalt and stone, as well as to measure moisture content. It uses low-level radioactive sources to emit gamma and neutron radiation to determine material density based on particle scattering. Whew! I just followed the science. Relieved? Yeah, me too. The purpose of all this is to ensure proper compaction of foundations, roadways, and embankments, hopefully preventing future infrastructure failures.

Let’s see how this is employed on a Howell project. Currently, we are working on a large subdivision that is in the bulk earthmoving phase of construction. Mass fill is being trucked to one side of the site to build the sediment basin, lot pads and interior roadways. The fill will typically be spread in 12” lifts in a certain area, like a lot pad. Once the fill is placed, it gets rolled by a vibratory roller for a minimum of two passes. Then it’s time to be tested for proper compaction with the nuclear density meter. For a 12” lift, we hammer a pin into the compacted fill to a depth of 6 inches, place the gauge and release the rod into the soil to get a reading. The numbers the gauge spits out are compared to the proctor of the soil on site. This proctor provides us with the optimum dry density and moisture content. Hopefully, the readings fall within those proctor numbers. This happens all over the site, wherever they are placing fill that needs to be compacted. This process is essential for quality control, providing results in a matter of minutes rather than days compared to traditional lab testing.

You can see that this is a laborious, yet essential process to ensure infrastructure success. Many thanks to Howell for providing me with all these opportunities to contribute to the team's success!