Repair and Rehabilitation of Concrete Structures

Repair of concrete structures has been a focus of attention in recent years not only in Japan but also worldwide. Concrete structures have fallen short of expectations at the time of construction-they should have been perpetual and maintenance-free. However, investigation into their premature deterioration reveals the primary causes: Concrete was made using inadequate materials and/or inadequate mixture proportions due to insufficient consideration and was placed inadequately under insufficient execution control. The secondary causes include insufficient consideration at the time of construction for the environmental conditions to which the structures were to be exposed. In any event, in the current economic climate, structures cannot be demolished and rebuilt as soon as they are damaged, but instead are expected to continue to be in service as long as possible with appropriate repair or retrofitting. This paper analyzes the causes of deterioration requiring repair and introduces relevant repair techniques. At the end, the repair project of the Sanyo Shinkansen Line in which the author was involved through committee activities is reported.