Pre-Cooling Method using Liquefied Nitrogen in Dam Concrete

Abstract

Ohkawase dam is a gravity dam of concrete volume approximately 110000 m³. As the technical specification requires that the temperature of placing concrete shall be below 25°C, so we adopted the pre-cooling method in the summer time, in which Liquefied Nitrogen (LN₂) is injected to the concrete. By applying this method, we placed the concrete of 12000m³. This paper describes the plans and the results of consideration relating to the concreting which adopts the pre-cooling method.