Kelly Ball Drop to determine suitability for backfill per ASTM D 6024
This test method involves dropping the steel ball five times on the surface of the “set” CLSM material and measuring the diameter of the impression per ASTM D 6024, "Standard Test Method for Ball Drop on Controlled Low Strength Material (CLSM) to Determine the Suitability of Load Application".
The steel ball and handle weigh roughly 30-33 lbs; backfill can occur on the placed CLSM when the measured diameter of the impression is 3-inches or less.