a method for recovering usable material from waste concrete is herein described . specifically , waste concrete is mixed with water containing hydration stabilization admixtures , forming an aggregate slurry . the aggregates are then removed from the slurry for recycling . the slurry itself is then used for mixing with additional waste concrete , during which time the density of the slurry is monitored and action taken to ensure that the density of the slurry remains within acceptable parameters . the slurry is then used in place of fresh water when preparing subsequent batches of concrete .