Study for Improvement of Under Water Concreting at Marine Fields

This report gives the outline of a technical development for the under water concreting carried out at Hokkaido during the past two years. The research for the advancement of construction technique is performed by collecting and analyzing the data as for the mix proportions, concreting, quality of concrete and others on the base of the practical construction in marine fields. From the surveying results, it is ascertained that the characteristics concerned with concrete quality and the properties of the concreting have an influence with the compressive strenght, frost resistance and so on. It is found that the new casing-system for under water concreting is available for a measure to prevent the segregation due to free dropping.