Improvement of Efficiency of Crashed Sand Production by Underwater Pulsed Discharge

Concrete indispensable as building and roadbed material consists of coarse aggregates, fine aggregates, and cement pastes. Fine aggregates have been collected from riverbeds and seaside, or manufactured by cracking rocks from mountains area into small pieces with a crusher. Recently in Japan, it is banned to collect fine aggregates from rivers and sea because of the collection regulation due to fear of natural resource depletion. Therefore, the demand for regenerated fine aggregate and crushed sand as artificial aggregates have been increasing, and these are currently manufactured by a crasher which requires huge equipment. Therefore, new crushing technology is needed, and one of them is expected to be the crushing technology using pulse power. Pulsed power technology is possible to crack rocks by utilizing the dielectric breakdown phenomenon in liquids and the shock-wave generated by underwater discharge.