Abstract
The decommissioning and dismantling of nuclear power plants will produce a large quantity of non-active waste concrete. From the viewpoint of recycling of this waste concrete the recovery of aggregate contained in concrete at 80% and reuse of it into a new plant construction are envisioned. For these purposes we have studied the recovery process of aggregate from concrete composed of a heating step followed by a milling step onto waste concrete blocks. We have found that higher operation temperature brings a better effect for the separation of aggregate from a concrete body, however too high temperature may reversely degrade a quality of recovered aggregate itself. The most effective heating temperature which is considered not to give the damage to a quality of aggregate stays between 200～500℃. The effect of a duration at such temperature zone is relatively small. As a conclusion we have found that 300℃ of heating temperature and 30～120 minutes of a duration in a rod mill with high efficiency of rubbing work for getting coarse aggregate and an agitate mill for fine aggregate might be proper operating conditions under which we can recover both coarse and fine aggregate with the quality within JASS 5N standard.
