Do you have any information concerning the relationship between the cost of concrete and the density?
We assume that this question concerns high density concrete of the kind used for shielding. About ten years ago Brookhaven National Laboratory published a graph which showed that density could be increased up to about 240 pounds per cubic foot while holding cost of concrete material alone below $100 per cubic yard. For densities much over 240 pounds per cubic foot the cost curve steepens dramatically. At 300 pounds per cubic foot cost jumps to $300 per cubic yard; at 350 pounds per cubic foot it approximates $470 per cubic yard. Since these figures are at least ten years old, they should obviously be adjusted upward to take account of inflation.