Papers by Author: Hiroyuki Miyauchi

Abstract: Recently, the damaged building and loss of life have been increasing by man-made disasters. In this study, the blast resistance performance of fiber reinforced concrete against explosion was evaluated by the emulsion explosive and AUTODYN. The concrete without fiber was penetrated by emulsion explosive of 4605 kJ/kg and its back side was fractured heavily. The concretes with PVA, PE and Steel fiber have a higher blast resistance than that of concrete without fiber. Consequentially, the blast resistance of concrete was analyzed from viewpoint of fracture mode by AUTODYN and it was concluded that the fiber content is a beneficial for the blast resistance performance of concrete.

Abstract: The early-age properties and relationships between hydration heat and autogenous shrinkage in high-strength mass concrete are investigated through analysis of the history curves of hydration heat and autogenous shrinkage. To reduce the hydration heat velocity, micro encapsulated retarder (MR) that could retard cement reaction was applied. In the result of research, the hydration temperature and hydration heat velocity of high-strength mass concrete can be decreased with the reduction of size specimen and use of the retarder. A close relationship could be found between the hydration temperature and autogenous shrinkage; the higher the hydration heat velocity, the higher the autogenous shrinkage velocity and the greater the ultimate autogenous shrinkage.