There are many earthquakes in Japan. If a large earthquake were to occur, it is necessary to consider how pipelines such as: gas, sewage, telecommunications, and so on are restored quickly. At that time, damaged gas pipelines are very dan- gerous because fire in large areas could be caused by the leakage of gas from the damaged pipeline. Accordingly, it is necessary for gas companies to stop the supply of gas to houses over a large area. Once the gas supply is stopped, there is a considerable amount of time to repair the pipelines over the area. For this reason, a quick method for restoring damaged gas pipelines would be useful after an earthquake. Recently, we have been developing new flash setting mate- rial for the damaged gas pipeline by an injection into the house connection of gas when the gas supply is stopped quickly in an emergency. From these points of view, in order to clarify to what degree the contents of flash settling ma- terial affect the properties of the injected fly ash mixture causing heavy damage to the gas pipeline in an earthquake, different combinations of fly ash, chemical agents and water were considered in several experiments.