This seemed a good idea in the early 2000’s, when more paddock areas at race circuits got tarmacced. However I remember at Rockingham, those teams that had employed that method, getting hefty bills for the tarmac repairs. Word got round, and suddenly 56lb weights became gold dust.
The last time I used them on tarmac was at Spa Francorchamps and we put plastic bottles (split up the side) over them in case anyone passed comment. I’ve banged them into gravel numerous times and even when there’s a hardcore base under the gravel they go straight in and hold things down