Abstract
In order to establish methods for producing durable concrete, it seems to be necessary to make a detailed investigation on deterioration of exposed concrete structures in the field, besides laboratory experiments. In this investigation, a large number of road bridges were examined and many points which should be considered in the constructing and designing of bridges were found. The deterioration observed seems to be mainly caused by poor construction, but in many cases deterioration could be avoided by careful considerations to questions of design of concrete. It is expected that the details of structural design proposed here could be helpful in preventing deterioration due to freezing and thawing.
