Shin-ichiro Hashimoto

Effects of curing conditions and addition of fine blast furnace slag powder on the initial performance of concrete using expanding material

In this study was investigated the effect of steam curing in the case of adding expandable material to powdery high fluidity concrete containing blast furnace slag fine powder on two kinds of expansive materials, ettringite type inflation material and lime type expansion material. As a result, the constraint expansion strain increases with the ettringite type due to the increase in the steam curing temperature. However, it was confirmed that it decreased with the lime type expansion material.

DEVELOPMENT OF SIMPLE FREEZING AND THAWING TEST USING LIQUID NITROGEN

In this research, an apparatus for a simple freezing and thawing test using liquid nitrogen that enables measurement to be carried out even in actual structures has been developed based on existing research studies as a new testing method replacing the freezing and thawing test of concrete defined in the Japanese Industrial Standards (JIS), and a reviews was made of its practicality. The results indicated that, when used in conjunction with ultrasonic measurement equipment, the apparatus for a simple freezing and thawing test using liquid nitrogen was capable of evaluating the degradation of concrete surfaces part after only a small number of cycles and was greatly effective in practical application.