Lime sludge is lime rock broken down to a fine powder.  You will need to sprinkle the work area with water during dry days it is that fine.  When dried the material becomes solid no perk.  Even though the material has no perk properties many projects have been covered with 3/4 to 1 inch of muck with no flooding issues.  Ideal for horses due to the fineness yet solid base to be covered with sand or grass.