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.